I have a number of used but still functional car batteries which I use
for electric fencers and lighting at a stables with no power.

Some are sealed, but for the ones with removable caps I always remove
the cap and check the acid level before putting them on the charger.

I have just one battery which always has low fluid in every cell when I
bring it back for recharge. It takes an exceptional amount of demin
water each time, at least 50 ml per cell if not more. All the cells are
similar. But, when recharged, it reaches a reasonable voltage and
certainly holds a useful amount of charge.

The cells can't be leaking significantly, firstly there is no sign of it
and secondly this must have done a dozen cycles like this over the past
year or two. I havn't actually checked the acid concentration, I
probably should, and top it up if necessary.

Does anyone have an explanation?

On 17/11/17 17:18, newshound wrote:
I have a number of used but still functional car batteries which I use
for electric fencers and lighting at a stables with no power.

Some are sealed, but for the ones with removable caps I always remove
the cap and check the acid level before putting them on the charger.

I have just one battery which always has low fluid in every cell when I
bring it back for recharge. It takes an exceptional amount of demin
water each time, at least 50 ml per cell if not more. All the cells are
similar. But, when recharged, it reaches a reasonable voltage and
certainly holds a useful amount of charge.

The cells can't be leaking significantly, firstly there is no sign of it
and secondly this must have done a dozen cycles like this over the past
year or two. I havn't actually checked the acid concentration, I
probably should, and top it up if necessary.

Does anyone have an explanation?

internal short maybe on that cell


--
Socialism is the philosophy of failure, the creed of ignorance and the
gospel of envy.

Its inherent virtue is the equal sharing of misery.

Winston Churchill

On 17/11/2017 17:23, The Natural Philosopher wrote:
On 17/11/17 17:18, newshound wrote:
I have a number of used but still functional car batteries which I use
for electric fencers and lighting at a stables with no power.

Some are sealed, but for the ones with removable caps I always remove
the cap and check the acid level before putting them on the charger.

I have just one battery which always has low fluid in every cell when
I bring it back for recharge. It takes an exceptional amount of demin
water each time, at least 50 ml per cell if not more. All the cells
are similar. But, when recharged, it reaches a reasonable voltage and
certainly holds a useful amount of charge.

The cells can't be leaking significantly, firstly there is no sign of
it and secondly this must have done a dozen cycles like this over the
past year or two. I havn't actually checked the acid concentration, I
probably should, and top it up if necessary.

Does anyone have an explanation?

internal short maybe on that cell


But it is *every* cell, and it does hold a reasonable amount of charge.

On 17/11/2017 17:18, newshound wrote:
I have a number of used but still functional car batteries which I use
for electric fencers and lighting at a stables with no power.

Some are sealed, but for the ones with removable caps I always remove
the cap and check the acid level before putting them on the charger.

I have just one battery which always has low fluid in every cell when I
bring it back for recharge. It takes an exceptional amount of demin
water each time, at least 50 ml per cell if not more. All the cells are
similar. But, when recharged, it reaches a reasonable voltage and
certainly holds a useful amount of charge.

The cells can't be leaking significantly, firstly there is no sign of it
and secondly this must have done a dozen cycles like this over the past
year or two. I havn't actually checked the acid concentration, I
probably should, and top it up if necessary.

Does anyone have an explanation?

Do you do a similar check after it has been charged?

I would expect any water usage would be in the charge cycle.

On Friday, 17 November 2017 17:18:30 UTC, newshound wrote:
I have a number of used but still functional car batteries which I use
for electric fencers and lighting at a stables with no power.

Some are sealed, but for the ones with removable caps I always remove
the cap and check the acid level before putting them on the charger.

I have just one battery which always has low fluid in every cell when I
bring it back for recharge. It takes an exceptional amount of demin
water each time, at least 50 ml per cell if not more. All the cells are
similar. But, when recharged, it reaches a reasonable voltage and
certainly holds a useful amount of charge.

The cells can't be leaking significantly, firstly there is no sign of it
and secondly this must have done a dozen cycles like this over the past
year or two. I havn't actually checked the acid concentration, I
probably should, and top it up if necessary.

Does anyone have an explanation?

ponies with strange taste?
Water is normally lost during charging rather than any other time, but 50ml a charge is a huge amount.


NT

On 17/11/2017 18:02, Fredxxx wrote:
On 17/11/2017 17:18, newshound wrote:
I have a number of used but still functional car batteries which I use
for electric fencers and lighting at a stables with no power.

Some are sealed, but for the ones with removable caps I always remove
the cap and check the acid level before putting them on the charger.

I have just one battery which always has low fluid in every cell when
I bring it back for recharge. It takes an exceptional amount of demin
water each time, at least 50 ml per cell if not more. All the cells
are similar. But, when recharged, it reaches a reasonable voltage and
certainly holds a useful amount of charge.

The cells can't be leaking significantly, firstly there is no sign of
it and secondly this must have done a dozen cycles like this over the
past year or two. I havn't actually checked the acid concentration, I
probably should, and top it up if necessary.

Does anyone have an explanation?

Do you do a similar check after it has been charged?

I would expect any water usage would be in the charge cycle.

Yes, so would I. I stop charging when all the cells are fizzing nicely
and don't normally have to top up again at that stage.

On 17/11/2017 18:11, wrote:
On Friday, 17 November 2017 17:18:30 UTC, newshound wrote:
I have a number of used but still functional car batteries which I use
for electric fencers and lighting at a stables with no power.

Some are sealed, but for the ones with removable caps I always remove
the cap and check the acid level before putting them on the charger.

I have just one battery which always has low fluid in every cell when I
bring it back for recharge. It takes an exceptional amount of demin
water each time, at least 50 ml per cell if not more. All the cells are
similar. But, when recharged, it reaches a reasonable voltage and
certainly holds a useful amount of charge.

The cells can't be leaking significantly, firstly there is no sign of it
and secondly this must have done a dozen cycles like this over the past
year or two. I havn't actually checked the acid concentration, I
probably should, and top it up if necessary.

Does anyone have an explanation?

ponies with strange taste?
Water is normally lost during charging rather than any other time, but 50ml a charge is a huge amount.


NT

Yes I know. That's why I am mystified. I've been looking after lead acid
batteries for over fifty years, and have never had one behave like this
before.

newshound wrote:
I have a number of used but still functional car batteries which I use
for electric fencers and lighting at a stables with no power.

Some are sealed, but for the ones with removable caps I always remove
the cap and check the acid level before putting them on the charger.

I have just one battery which always has low fluid in every cell when
I bring it back for recharge. It takes an exceptional amount of demin
water each time, at least 50 ml per cell if not more. All the cells
are similar. But, when recharged, it reaches a reasonable voltage and
certainly holds a useful amount of charge.

The cells can't be leaking significantly, firstly there is no sign of
it and secondly this must have done a dozen cycles like this over the
past year or two. I havn't actually checked the acid concentration, I
probably should, and top it up if necessary.

Does anyone have an explanation?

I seem to remember doing this in the old days.
With the caps off and the battery on charge, fluid would spit out all over
the battery.
Just a thought.

On 17/11/2017 18:17, newshound wrote:
On 17/11/2017 18:02, Fredxxx wrote:
On 17/11/2017 17:18, newshound wrote:
I have a number of used but still functional car batteries which I
use for electric fencers and lighting at a stables with no power.

Some are sealed, but for the ones with removable caps I always remove
the cap and check the acid level before putting them on the charger.

I have just one battery which always has low fluid in every cell when
I bring it back for recharge. It takes an exceptional amount of demin
water each time, at least 50 ml per cell if not more. All the cells
are similar. But, when recharged, it reaches a reasonable voltage and
certainly holds a useful amount of charge.

The cells can't be leaking significantly, firstly there is no sign of
it and secondly this must have done a dozen cycles like this over the
past year or two. I havn't actually checked the acid concentration, I
probably should, and top it up if necessary.

Does anyone have an explanation?

Do you do a similar check after it has been charged?

I would expect any water usage would be in the charge cycle.

Yes, so would I. I stop charging when all the cells are fizzing nicely
and don't normally have to top up again at that stage.

The fizzing sounds an issue. You ought not allow the battery voltage to
be high enough for cells to 'fizz'. A short equalisation charge is all
that is needed. What is the charge end current?

What do you mean by 'normally'? Perhaps gas on the plates is raising the
level such that after charge it looks ok. I would check sometime after
you've completed the charge process.

Next question! Do these batteries get much movement? I have heard of
electrolyte stratification being an issue that promotes gassing.

Have you checked the electrolyte density of this battery?

On 17/11/2017 18:19, newshound wrote:
On 17/11/2017 18:11, wrote:
On Friday, 17 November 2017 17:18:30 UTC, newshoundÂ* wrote:
I have a number of used but still functional car batteries which I use
for electric fencers and lighting at a stables with no power.

Some are sealed, but for the ones with removable caps I always remove
the cap and check the acid level before putting them on the charger.

I have just one battery which always has low fluid in every cell when I
bring it back for recharge. It takes an exceptional amount of demin
water each time, at least 50 ml per cell if not more. All the cells are
similar. But, when recharged, it reaches a reasonable voltage and
certainly holds a useful amount of charge.

The cells can't be leaking significantly, firstly there is no sign of it
and secondly this must have done a dozen cycles like this over the past
year or two. I havn't actually checked the acid concentration, I
probably should, and top it up if necessary.

Does anyone have an explanation?

ponies with strange taste?
Water is normally lost during charging rather than any other time, but
50ml a charge is a huge amount.


NT

Yes I know. That's why I am mystified. I've been looking after lead acid
batteries for over fifty years, and have never had one behave like this
before.

50g is 2.8 moles of water.

You would need 5.6 moles of electrons, so 540,000C

5 Amps would imply a gassing time of 10 days. So something strange is
going on, unless you keep it connected to the charger for 10 days or more?

On 17/11/2017 18:39, Fredxxx wrote:
On 17/11/2017 18:19, newshound wrote:
On 17/11/2017 18:11, wrote:
On Friday, 17 November 2017 17:18:30 UTC, newshoundÂ* wrote:
I have a number of used but still functional car batteries which I use
for electric fencers and lighting at a stables with no power.

Some are sealed, but for the ones with removable caps I always remove
the cap and check the acid level before putting them on the charger.

I have just one battery which always has low fluid in every cell when I
bring it back for recharge. It takes an exceptional amount of demin
water each time, at least 50 ml per cell if not more. All the cells are
similar. But, when recharged, it reaches a reasonable voltage and
certainly holds a useful amount of charge.

The cells can't be leaking significantly, firstly there is no sign
of it
and secondly this must have done a dozen cycles like this over the past
year or two. I havn't actually checked the acid concentration, I
probably should, and top it up if necessary.

Does anyone have an explanation?

ponies with strange taste?
Water is normally lost during charging rather than any other time,
but 50ml a charge is a huge amount.


NT

Yes I know. That's why I am mystified. I've been looking after lead
acid batteries for over fifty years, and have never had one behave
like this before.

50g is 2.8 moles of water.

You would need 5.6 moles of electrons, so 540,000C

5 Amps would imply a gassing time of 10 days. So something strange is
going on, unless you keep it connected to the charger for 10 days or more?

To reply to the two posts together, I recharge the batteries with a
traditional transformer/rectifier type car battery charger, so that the
current drops off as it becomes charged (because the cell voltage
rises). Once a cell becomes fully charged, the current it is passing
causes electrolysis, so it "fizzes". In old batteries, the capacity may
vary from cell to cell, so you may find one cell fizzing while another
is not, that's a good reason to keep charging until they all fizz, but
of course you do not want to concentrate the electrolyte by doing this
for too long.

I realise that a charged battery may still have some trapped hydrogen
and oxygen on the plates. So once it is charged, I will jiggle it and
leave it open for a day or two in the hope that the gas all escapes.
After that, I check the level and I don't normally find I need to add
any more demin water.

IIRC this was originally an 80 amp-hour battery and it certainly still
provides more than 10 AH at 12 volts, based on the lights that I run off
it. And it is usually powering a couple of PIR lights that also get
triggered through the night by cats, foxes, etc, so I suspect it's doing
better than that.

I'm certainly not charging it for ten days. Might leave it connected for
two days, and while the charger starts at 8 amps or so it has dropped to
an amp or so after a day.

On Fri, 17 Nov 2017 18:29:54 +0000, Fredxxx wrote:

snip

The fizzing sounds an issue. You ought not allow the battery voltage to
be high enough for cells to 'fizz'.

If we are talking about 'gassing' here then isn't it actually
*required* as part of the charge process of a flooded lead acid
battery to prevent electrolyte (and so charge) stratification?

http://batteryuniversity.com/learn/a...surface_charge

A short equalisation charge is all
that is needed. What is the charge end current?

I think the second part of your question may answer the first part.
;-)

The 'equalisation stage' duration would (of course) be a function of
the (bulk) charge rate and / or also a function of the charge profile
of an automatic charger.

Cheers, T i m

On Fri, 17 Nov 2017 19:24:05 +0000, newshound
wrote:

snip

To reply to the two posts together, I recharge the batteries with a
traditional transformer/rectifier type car battery charger, so that the
current drops off as it becomes charged (because the cell voltage
rises).

Ok.

Once a cell becomes fully charged, the current it is passing
causes electrolysis, so it "fizzes".

'As it becomes near to being fully charged ...' ;-)

In old batteries, the capacity may
vary from cell to cell,

I think that happens in all / new cells within the same battery but by
varying amounts. We used to minimise this (for racing) buy buying
batteries made from 'matched cells'.

so you may find one cell fizzing while another
is not, that's a good reason to keep charging until they all fizz,

And the last one 'to fizz' also needs to fizz for a while to minimise
stratification.

but
of course you do not want to concentrate the electrolyte by doing this
for too long.

I think the risk is more the water loss from the electrolyte in
general and exposing the plates than any change in 'concentration (as
that will be redressed when you top up with water again).

I realise that a charged battery may still have some trapped hydrogen
and oxygen on the plates. So once it is charged, I will jiggle it and
leave it open for a day or two in the hope that the gas all escapes.

And the water. ;-( Are you sure the cell caps aren't the
recombination type (designed to allow the cell to vent pressure but to
reduce the water loss)?

After that, I check the level and I don't normally find I need to add
any more demin water.

Assuming the electrolyte is above or at least level with the tops of
the plates, I think you are supposed to top up (after it's been fully
charged)?

IIRC this was originally an 80 amp-hour battery and it certainly still
provides more than 10 AH at 12 volts, based on the lights that I run off
it.

Ok (the C20Ah rate would be only tested at that rate etc). So, for
your 'calibration' of the battery as being 10Ah I believe you would
need 48W of 12V lamp and would need to time it down to 10.5V or
(ideally) higher (if not a deep cycle battery). So, for it to be 10Ah
you would be able to run your (48W) lamp for 2 hours or a 100W for
something less than 1hr?

And it is usually powering a couple of PIR lights that also get
triggered through the night by cats, foxes, etc, so I suspect it's doing
better than that.

Ok.

I'm certainly not charging it for ten days. Might leave it connected for
two days, and while the charger starts at 8 amps or so it has dropped to
an amp or so after a day.

That sounds pretty reasonable for a largish / old LA battery. ;-)

So, I might be tempted to not remove the cell plugs when (or after)
charging and see if that makes any difference to your electrolyte
loss.

Cheers, T i m

On 17/11/2017 17:18, newshound wrote:

Does anyone have an explanation?

Left out in a sunny sheltered location or indoors behind a window and
the water is just getting hot and evaporating?

--
mailto: news {at} admac {dot] myzen {dot} co {dot} uk

On 17/11/2017 20:09, T i m wrote:
On Fri, 17 Nov 2017 19:24:05 +0000, newshound
wrote:

snip

To reply to the two posts together, I recharge the batteries with a
traditional transformer/rectifier type car battery charger, so that the
current drops off as it becomes charged (because the cell voltage
rises).

Ok.

Once a cell becomes fully charged, the current it is passing
causes electrolysis, so it "fizzes".

'As it becomes near to being fully charged ...' ;-)

In old batteries, the capacity may
vary from cell to cell,

I think that happens in all / new cells within the same battery but by
varying amounts. We used to minimise this (for racing) buy buying
batteries made from 'matched cells'.

so you may find one cell fizzing while another
is not, that's a good reason to keep charging until they all fizz,

And the last one 'to fizz' also needs to fizz for a while to minimise
stratification.

but
of course you do not want to concentrate the electrolyte by doing this
for too long.

I think the risk is more the water loss from the electrolyte in
general and exposing the plates than any change in 'concentration (as
that will be redressed when you top up with water again).

Well also, you don't really want parts of the plates to "dry up".


I realise that a charged battery may still have some trapped hydrogen
and oxygen on the plates. So once it is charged, I will jiggle it and
leave it open for a day or two in the hope that the gas all escapes.

And the water. ;-( Are you sure the cell caps aren't the
recombination type (designed to allow the cell to vent pressure but to
reduce the water loss)?

Don't know. I used to work with a battery expert who knew all about this
stuff, because there are BIG backup batteries on both nuclear and
conventional power stations, but he retired to the wilds of Alberta.
Certainly those cells are recombination type, but I don't know about
ordinary car/tractor batteries.



After that, I check the level and I don't normally find I need to add
any more demin water.

Assuming the electrolyte is above or at least level with the tops of
the plates, I think you are supposed to top up (after it's been fully
charged)?

What I am saying is that before charging, I top up so that the water is
at the level of the marker above the plates, after charging the plates
are almost always still covered, so I don't normally feel the need to
add water then.


IIRC this was originally an 80 amp-hour battery and it certainly still
provides more than 10 AH at 12 volts, based on the lights that I run off
it.

Ok (the C20Ah rate would be only tested at that rate etc). So, for
your 'calibration' of the battery as being 10Ah I believe you would
need 48W of 12V lamp and would need to time it down to 10.5V or
(ideally) higher (if not a deep cycle battery). So, for it to be 10Ah
you would be able to run your (48W) lamp for 2 hours or a 100W for
something less than 1hr?

As an example, on the night of the big local firework display I got two
hours of light out of about 50 watts of CFL, and I'd estimate that I
have also had a similar amount of light out of the rest of the last charge.


And it is usually powering a couple of PIR lights that also get
triggered through the night by cats, foxes, etc, so I suspect it's doing
better than that.

Ok.

I'm certainly not charging it for ten days. Might leave it connected for
two days, and while the charger starts at 8 amps or so it has dropped to
an amp or so after a day.

That sounds pretty reasonable for a largish / old LA battery. ;-)

So, I might be tempted to not remove the cell plugs when (or after)
charging and see if that makes any difference to your electrolyte
loss.

Because you think they might be recombination type? But I am not really
losing water during charging. It is vanishing when the battery is in
service, with the caps on.


Cheers, T i m

On 17/11/2017 20:26, alan_m wrote:
On 17/11/2017 17:18, newshound wrote:

Does anyone have an explanation?

Left out in a sunny sheltered location or indoors behind a window and
the water is just getting hot and evaporating?

Good thought, but no. It's inside a shed which never gets particularly
warm because it is under trees, and in a valley orientated so that it
doesn't get much direct sun at the best of times. And its quite cool at
the moment. And it is only this one of about four batteries which
behaves like this. And you don't get anything like this evaporation in a
car battery even in the summer, with the combination of direct sun and
underbonnet heating from the engine.

On Fri, 17 Nov 2017 21:59:14 +0000, newshound
wrote:

snip

I think the risk is more the water loss from the electrolyte in
general and exposing the plates than any change in 'concentration (as
that will be redressed when you top up with water again).

Well also, you don't really want parts of the plates to "dry up".

Quite, but assuming you keep the cell caps on and top the cells up
after charging and check for any loss in between that might allow the
plates to become exposed, you should be ok?


I realise that a charged battery may still have some trapped hydrogen
and oxygen on the plates. So once it is charged, I will jiggle it and
leave it open for a day or two in the hope that the gas all escapes.

And the water. ;-( Are you sure the cell caps aren't the
recombination type (designed to allow the cell to vent pressure but to
reduce the water loss)?

Don't know. I used to work with a battery expert who knew all about this
stuff, because there are BIG backup batteries on both nuclear and
conventional power stations, but he retired to the wilds of Alberta.
Certainly those cells are recombination type, but I don't know about
ordinary car/tractor batteries.

'Ordinary of what age / spec. I think most recent wet LA batteries
(especially those marked as sealed but are still 'wet') I would think
they would (have to) be.



After that, I check the level and I don't normally find I need to add
any more demin water.

Assuming the electrolyte is above or at least level with the tops of
the plates, I think you are supposed to top up (after it's been fully
charged)?

What I am saying is that before charging, I top up so that the water is
at the level of the marker above the plates,

Understood. However, I think more electrolyte appears *after* charging
and so it could overfill the cell if you do it before.

after charging the plates
are almost always still covered, so I don't normally feel the need to
add water then.

No, quite and that would be expected. The 'issue' is that you should
check the electrolyte levels more regularly so that they are above the
plates at all times, not just as you are about to recharge them? ;-(

"If low on electrolyte, immediately fill the battery with distilled or
de-ionized water. Tap water may be acceptable in some regions. Do not
fill to the correct level before charging as this could cause an
overflow during charging. Always top up to the desired level after
charging."

http://batteryuniversity.com/learn/a...d_acid_battery


IIRC this was originally an 80 amp-hour battery and it certainly still
provides more than 10 AH at 12 volts, based on the lights that I run off
it.

Ok (the C20Ah rate would be only tested at that rate etc). So, for
your 'calibration' of the battery as being 10Ah I believe you would
need 48W of 12V lamp and would need to time it down to 10.5V or
(ideally) higher (if not a deep cycle battery). So, for it to be 10Ah
you would be able to run your (48W) lamp for 2 hours or a 100W for
something less than 1hr?

As an example, on the night of the big local firework display I got two
hours of light out of about 50 watts of CFL, and I'd estimate that I
have also had a similar amount of light out of the rest of the last charge.

Is that 50W 'equivalent of incandescent' (and so say 10W of electrical
load) or 50W of actual load?


And it is usually powering a couple of PIR lights that also get
triggered through the night by cats, foxes, etc, so I suspect it's doing
better than that.

Ok.

I'm certainly not charging it for ten days. Might leave it connected for
two days, and while the charger starts at 8 amps or so it has dropped to
an amp or so after a day.

That sounds pretty reasonable for a largish / old LA battery. ;-)

So, I might be tempted to not remove the cell plugs when (or after)
charging and see if that makes any difference to your electrolyte
loss.

Because you think they might be recombination type?

Yes but of any type really.

But I am not really
losing water during charging. It is vanishing when the battery is in
service, with the caps on.

Yes, I understand that and agree it doesn't make much sense. ;-(

If you buy a 'traditional' dry-charged LA wet motorcycle battery with
a electrolyte pack, after applying the electrolyte and allowing some
time (a few hours) for the plates to absorb it all, you fit the sealed
plugs and attach the external vent pipe. From then on the only time
you remove the plugs is if you need to top the cell(s) up with
distilled water.

If I then leave a bike unattended for a long period of time ('years')
I too would expect to see some plates exposed and find the battery
ruined (sulphated). The most likely reason therefore is evaporation?

Cheers, T i m

newshound wrote:
On 17/11/2017 20:09, T i m wrote:
On Fri, 17 Nov 2017 19:24:05 +0000, newshound
wrote:

snip

To reply to the two posts together, I recharge the batteries with a
traditional transformer/rectifier type car battery charger, so that the
current drops off as it becomes charged (because the cell voltage
rises).

Ok.

Once a cell becomes fully charged, the current it is passing
causes electrolysis, so it "fizzes".

'As it becomes near to being fully charged ...' ;-)

In old batteries, the capacity may
vary from cell to cell,

I think that happens in all / new cells within the same battery but by
varying amounts. We used to minimise this (for racing) buy buying
batteries made from 'matched cells'.

so you may find one cell fizzing while another
is not, that's a good reason to keep charging until they all fizz,

And the last one 'to fizz' also needs to fizz for a while to minimise
stratification.

but
of course you do not want to concentrate the electrolyte by doing this
for too long.

I think the risk is more the water loss from the electrolyte in
general and exposing the plates than any change in 'concentration (as
that will be redressed when you top up with water again).

Well also, you don't really want parts of the plates to "dry up".


I realise that a charged battery may still have some trapped hydrogen
and oxygen on the plates. So once it is charged, I will jiggle it and
leave it open for a day or two in the hope that the gas all escapes.

And the water. ;-( Are you sure the cell caps aren't the
recombination type (designed to allow the cell to vent pressure but to
reduce the water loss)?

Don't know. I used to work with a battery expert who knew all about this
stuff, because there are BIG backup batteries on both nuclear and
conventional power stations, but he retired to the wilds of Alberta.
Certainly those cells are recombination type, but I don't know about
ordinary car/tractor batteries.



After that, I check the level and I don't normally find I need to add
any more demin water.

Assuming the electrolyte is above or at least level with the tops of
the plates, I think you are supposed to top up (after it's been fully
charged)?

What I am saying is that before charging, I top up so that the water is
at the level of the marker above the plates, after charging the plates
are almost always still covered, so I don't normally feel the need to
add water then.


IIRC this was originally an 80 amp-hour battery and it certainly still
provides more than 10 AH at 12 volts, based on the lights that I run off
it.

Ok (the C20Ah rate would be only tested at that rate etc). So, for
your 'calibration' of the battery as being 10Ah I believe you would
need 48W of 12V lamp and would need to time it down to 10.5V or
(ideally) higher (if not a deep cycle battery). So, for it to be 10Ah
you would be able to run your (48W) lamp for 2 hours or a 100W for
something less than 1hr?

As an example, on the night of the big local firework display I got two
hours of light out of about 50 watts of CFL, and I'd estimate that I
have also had a similar amount of light out of the rest of the last charge.


And it is usually powering a couple of PIR lights that also get
triggered through the night by cats, foxes, etc, so I suspect it's doing
better than that.

Ok.

I'm certainly not charging it for ten days. Might leave it connected for
two days, and while the charger starts at 8 amps or so it has dropped to
an amp or so after a day.

That sounds pretty reasonable for a largish / old LA battery. ;-)

So, I might be tempted to not remove the cell plugs when (or after)
charging and see if that makes any difference to your electrolyte
loss.

Because you think they might be recombination type? But I am not really
losing water during charging. It is vanishing when the battery is in
service, with the caps on.


Cheers, T i m


Is this battery in open in bright sun oran enclosure that gets very hot?

On Fri, 17 Nov 2017 19:24:05 +0000, newshound wrote:

====snip====


IIRC this was originally an 80 amp-hour battery and it certainly still
provides more than 10 AH at 12 volts, based on the lights that I run off
it. And it is usually powering a couple of PIR lights that also get
triggered through the night by cats, foxes, etc, so I suspect it's doing
better than that.

Even assuming a capacity of 20AH, that's still only 25% of its original
capacity.


I'm certainly not charging it for ten days. Might leave it connected for
two days, and while the charger starts at 8 amps or so it has dropped to
an amp or so after a day.

Quite frankly, I think, at a mere 25% of capacity, the battery is well
and truly "Shagged". I used to run two banks of 'revived' ex-pabx
batteries[1] for about a decade before the cells finally became too
thirsty to justify the cost of distilled water and the energy to keep
them charged.

Although there was plenty of space beneath the plates, the paste in the
plate grid structure had eventually disintegrated enough to form a
significant layer of debris in the bottom of the cells where it could no
longer provide its original function as plate anode material and, if not
actually shorting the plates, it was certainly increasing the self
discharge leakage rate (hence their thirstyness). I'd had a good ten
years worth of service out of 'My Freeby' by then so finally decided to
call it a day and weighed them in for scrap (along with a collection of
similarly buggered SLAs and car batteries).

One thing to note with SLI batteries is that they're totally unsuited to
use as UPS battery packs. It took 3 expensive lessons before I finally
realised this. Mind you the first lesson was over ten years prior to the
last two and only involved a single car battery connected to a 4A rated
13.8v CB radio mains PSU rather than the strings of 4 used with an APC
SmartUPS2000 just a few years ago.

It seems that the continuous float charging 24/7 at 13.8v per car
battery is what does them in after just 6 months or so of UPS service.

When used for their intended purpose (Starting Lighting Ignition), they
thrive quite happily on their regimen of 14.2v intermittent charging and
brief bursts of 100 plus amps starting loads along with the various
accelerations associated with accelerating/braking and sideways G forces
generated when negotiating corners and tight bends. It seems the 'rough
mechanical handling' keeps the electrolyte nicely stirred up and
homogenised preventing a deleterious density gradient in the electrolyte
that otherwise builds up when wet cell batteries are used in a fixed
location.

I reckon there was still more than 50% capacity in those car batteries
by the time they became a maintenance liability and an unnecessary drain
of charging power demand on the UPS. I have a theory that by sacrificing
some some 5 or 10 percent of usable capacity by reducing the float
charging voltage to 13.5v per car battery instead of the "standard 13.8v"
normally used by APC UPSes, I might be able to get a better than 5 year
service life. However, I haven't had the heart to put this to the test so
it remains just a theory.

Getting back to your 'battery mystery', I'd say you're simply dealing
with a battery that's long gone past its Best Before Date and is well and
truly ready to be weighed in.

[1] When I discovered them in a decommissioned PABX, the battery had been
disassembled into individual 125AH Tungstone cells and simply left
standing for Ghod knows how many years. I picked the best 12 cells out of
the 25 that had been left in a completely discharged state to haul back
to my basement radio shack and connected each one to a basic 4A 12v
battery charger via a current limiting 21W 12v indicator lamp until the
almost pure water finally became reactivated with the electrode bound
acid and the lamp started to glow before rigging a string of 6 at a time
to let me connect them directly to the battery charger (doing this for
two bank's worth).

Having revived them sufficiently to be charged as 12v batteries in the
conventional way, I then rigged up a dummy load made up of three 0.3 ohm
100W resistors in series and boiled a few bucket's worth of water
discharging them after each charge or reverse charging cycle until I was
satisfied I'd restored them to as good a state as I could. It seemed I'd
managed to get the capacity of each bank to circa 100AH at the 200 hour
discharge rate - just over a week's worth running the 1.05A load from my
VHF packet radio station setup.

--
Johnny B Good

Could it simply be situated in a very warm place or maybe it is dealing with
a higher load on a smaller battery. If its evaporation those plugged cells
do leak much more than completely sealed ones will of course.
Brian

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"newshound" wrote in message
...
I have a number of used but still functional car batteries which I use for
electric fencers and lighting at a stables with no power.

Some are sealed, but for the ones with removable caps I always remove the
cap and check the acid level before putting them on the charger.

I have just one battery which always has low fluid in every cell when I
bring it back for recharge. It takes an exceptional amount of demin water
each time, at least 50 ml per cell if not more. All the cells are similar.
But, when recharged, it reaches a reasonable voltage and certainly holds a
useful amount of charge.

The cells can't be leaking significantly, firstly there is no sign of it
and secondly this must have done a dozen cycles like this over the past
year or two. I havn't actually checked the acid concentration, I probably
should, and top it up if necessary.

Does anyone have an explanation?

No he says all the cells and the way to see the short would be to just leave
it in a cool place for a while without using it.
Brian

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"The Natural Philosopher" wrote in message
news
On 17/11/17 17:18, newshound wrote:
I have a number of used but still functional car batteries which I use
for electric fencers and lighting at a stables with no power.

Some are sealed, but for the ones with removable caps I always remove the
cap and check the acid level before putting them on the charger.

I have just one battery which always has low fluid in every cell when I
bring it back for recharge. It takes an exceptional amount of demin water
each time, at least 50 ml per cell if not more. All the cells are
similar. But, when recharged, it reaches a reasonable voltage and
certainly holds a useful amount of charge.

The cells can't be leaking significantly, firstly there is no sign of it
and secondly this must have done a dozen cycles like this over the past
year or two. I havn't actually checked the acid concentration, I probably
should, and top it up if necessary.

Does anyone have an explanation?

internal short maybe on that cell


--
Socialism is the philosophy of failure, the creed of ignorance and the
gospel of envy.

Its inherent virtue is the equal sharing of misery.

Winston Churchill

I'd be tempted to monitor the charge current and see what it is. Normally on
a well designed charger its very low when fully charged, if that one is
still charging high then it might well be that exception that has dodgyness
in all cells.
Brian

--
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"newshound" wrote in message
o.uk...
On 17/11/2017 18:02, Fredxxx wrote:
On 17/11/2017 17:18, newshound wrote:
I have a number of used but still functional car batteries which I use
for electric fencers and lighting at a stables with no power.

Some are sealed, but for the ones with removable caps I always remove
the cap and check the acid level before putting them on the charger.

I have just one battery which always has low fluid in every cell when I
bring it back for recharge. It takes an exceptional amount of demin
water each time, at least 50 ml per cell if not more. All the cells are
similar. But, when recharged, it reaches a reasonable voltage and
certainly holds a useful amount of charge.

The cells can't be leaking significantly, firstly there is no sign of it
and secondly this must have done a dozen cycles like this over the past
year or two. I havn't actually checked the acid concentration, I
probably should, and top it up if necessary.

Does anyone have an explanation?

Do you do a similar check after it has been charged?

I would expect any water usage would be in the charge cycle.

Yes, so would I. I stop charging when all the cells are fizzing nicely and
don't normally have to top up again at that stage.

On 17/11/2017 22:33, T i m wrote:
On Fri, 17 Nov 2017 21:59:14 +0000, newshound
wrote:

snip

I think the risk is more the water loss from the electrolyte in
general and exposing the plates than any change in 'concentration (as
that will be redressed when you top up with water again).

Well also, you don't really want parts of the plates to "dry up".

Quite, but assuming you keep the cell caps on and top the cells up
after charging and check for any loss in between that might allow the
plates to become exposed, you should be ok?


I realise that a charged battery may still have some trapped hydrogen
and oxygen on the plates. So once it is charged, I will jiggle it and
leave it open for a day or two in the hope that the gas all escapes.

And the water. ;-( Are you sure the cell caps aren't the
recombination type (designed to allow the cell to vent pressure but to
reduce the water loss)?

Don't know. I used to work with a battery expert who knew all about this
stuff, because there are BIG backup batteries on both nuclear and
conventional power stations, but he retired to the wilds of Alberta.
Certainly those cells are recombination type, but I don't know about
ordinary car/tractor batteries.

'Ordinary of what age / spec. I think most recent wet LA batteries
(especially those marked as sealed but are still 'wet') I would think
they would (have to) be.

I agree, modern "sealed" batteries are likely to be. IIRC this one was
on a car about 15 years old (but it would have been replaced at least once).




After that, I check the level and I don't normally find I need to add
any more demin water.

Assuming the electrolyte is above or at least level with the tops of
the plates, I think you are supposed to top up (after it's been fully
charged)?

What I am saying is that before charging, I top up so that the water is
at the level of the marker above the plates,

Understood. However, I think more electrolyte appears *after* charging
and so it could overfill the cell if you do it before.

after charging the plates
are almost always still covered, so I don't normally feel the need to
add water then.

No, quite and that would be expected. The 'issue' is that you should
check the electrolyte levels more regularly so that they are above the
plates at all times, not just as you are about to recharge them? ;-(

"If low on electrolyte, immediately fill the battery with distilled or
de-ionized water. Tap water may be acceptable in some regions. Do not
fill to the correct level before charging as this could cause an
overflow during charging. Always top up to the desired level after
charging."

http://batteryuniversity.com/learn/a...d_acid_battery

Hadn't come across that point before, although I have seen small
motorcycle batteries with a sort of overflow pipe. On a Japanese bike
you are trying to get maximum capacity in minimum volume, so the plates
are going to go near the top. But on this battery which came from a
diesel car but curiously is identical to the battery on my old tractor
there's a good half an inch of space between the level marker and the
bottom of the cap threads. I agree that you might expect some change of
volume between discharged and fully charged but its not an effect I have
ever noticed on car batteries.



IIRC this was originally an 80 amp-hour battery and it certainly still
provides more than 10 AH at 12 volts, based on the lights that I run off
it.

Ok (the C20Ah rate would be only tested at that rate etc). So, for
your 'calibration' of the battery as being 10Ah I believe you would
need 48W of 12V lamp and would need to time it down to 10.5V or
(ideally) higher (if not a deep cycle battery). So, for it to be 10Ah
you would be able to run your (48W) lamp for 2 hours or a 100W for
something less than 1hr?

As an example, on the night of the big local firework display I got two
hours of light out of about 50 watts of CFL, and I'd estimate that I
have also had a similar amount of light out of the rest of the last charge.

Is that 50W 'equivalent of incandescent' (and so say 10W of electrical
load) or 50W of actual load?

Actual load. IIRC, four 11s and a 9, or something like that.



And it is usually powering a couple of PIR lights that also get
triggered through the night by cats, foxes, etc, so I suspect it's doing
better than that.

Ok.

I'm certainly not charging it for ten days. Might leave it connected for
two days, and while the charger starts at 8 amps or so it has dropped to
an amp or so after a day.

That sounds pretty reasonable for a largish / old LA battery. ;-)

So, I might be tempted to not remove the cell plugs when (or after)
charging and see if that makes any difference to your electrolyte
loss.

Because you think they might be recombination type?

Yes but of any type really.

But I am not really
losing water during charging. It is vanishing when the battery is in
service, with the caps on.

Yes, I understand that and agree it doesn't make much sense. ;-(

If you buy a 'traditional' dry-charged LA wet motorcycle battery with
a electrolyte pack, after applying the electrolyte and allowing some
time (a few hours) for the plates to absorb it all, you fit the sealed
plugs and attach the external vent pipe. From then on the only time
you remove the plugs is if you need to top the cell(s) up with
distilled water.

If I then leave a bike unattended for a long period of time ('years')
I too would expect to see some plates exposed and find the battery
ruined (sulphated). The most likely reason therefore is evaporation?

Cheers, T i m

On 17/11/2017 23:24, FMurtz wrote:

Is this battery in open in bright sun oran enclosure that gets very hot?

No.

On 18/11/2017 01:56, Johnny B Good wrote:
On Fri, 17 Nov 2017 19:24:05 +0000, newshound wrote:

====snip====


IIRC this was originally an 80 amp-hour battery and it certainly still
provides more than 10 AH at 12 volts, based on the lights that I run off
it. And it is usually powering a couple of PIR lights that also get
triggered through the night by cats, foxes, etc, so I suspect it's doing
better than that.

Even assuming a capacity of 20AH, that's still only 25% of its original
capacity.


I'm certainly not charging it for ten days. Might leave it connected for
two days, and while the charger starts at 8 amps or so it has dropped to
an amp or so after a day.

Quite frankly, I think, at a mere 25% of capacity, the battery is well
and truly "Shagged". I used to run two banks of 'revived' ex-pabx
batteries[1] for about a decade before the cells finally became too
thirsty to justify the cost of distilled water and the energy to keep
them charged.

Yes it is certainly shagged from an automotive viewpoint, but it gives
me a month or so of "free" lighting at the stables. And of course unlike
a UPS this isn't in any way a critical application, I normally have a
spare ready to go.

interesting stuff snipped

On Sat, 18 Nov 2017 20:02:47 +0000, newshound
wrote:

snip

'Ordinary of what age / spec. I think most recent wet LA batteries
(especially those marked as sealed but are still 'wet') I would think
they would (have to) be.

I agree, modern "sealed" batteries are likely to be.

If they were truly sealed (as in not operable for refilling) they
would have to be.

IIRC this one was
on a car about 15 years old (but it would have been replaced at least once).

Is that like Triggers broom? ;-)

Hmm, the technology has been about for some time now but you might be
able to tell if they are by looking at them. eg, If they are obviously
a plain plastic cap then they aren't. ;-)

https://www.sunaxy.com/products/roll...on-battery-cap

snip

No, quite and that would be expected. The 'issue' is that you should
check the electrolyte levels more regularly so that they are above the
plates at all times, not just as you are about to recharge them? ;-(

"If low on electrolyte, immediately fill the battery with distilled or
de-ionized water. Tap water may be acceptable in some regions. Do not
fill to the correct level before charging as this could cause an
overflow during charging. Always top up to the desired level after
charging."

http://batteryuniversity.com/learn/a...d_acid_battery

Hadn't come across that point before, although I have seen small
motorcycle batteries with a sort of overflow pipe. On a Japanese bike
you are trying to get maximum capacity in minimum volume, so the plates
are going to go near the top. But on this battery which came from a
diesel car but curiously is identical to the battery on my old tractor
there's a good half an inch of space between the level marker and the
bottom of the cap threads. I agree that you might expect some change of
volume between discharged and fully charged but its not an effect I have
ever noticed on car batteries.

Shouldn't the same theory apply to any flooded lead acid battery
whatever it was to be used on. ;-)

snip

As an example, on the night of the big local firework display I got two
hours of light out of about 50 watts of CFL, and I'd estimate that I
have also had a similar amount of light out of the rest of the last charge.

Is that 50W 'equivalent of incandescent' (and so say 10W of electrical
load) or 50W of actual load?

Actual load. IIRC, four 11s and a 9, or something like that.

Ok.

Cheers, T i m

On Saturday, 18 November 2017 20:51:27 UTC, T i m wrote:
On Sat, 18 Nov 2017 20:02:47 +0000, newshound
wrote:

snip

'Ordinary of what age / spec. I think most recent wet LA batteries
(especially those marked as sealed but are still 'wet') I would think
they would (have to) be.

I agree, modern "sealed" batteries are likely to be.

If they were truly sealed (as in not operable for refilling) they
would have to be.

IIRC this one was
on a car about 15 years old (but it would have been replaced at least once).

Is that like Triggers broom? ;-)

Hmm, the technology has been about for some time now but you might be
able to tell if they are by looking at them. eg, If they are obviously
a plain plastic cap then they aren't. ;-)

https://www.sunaxy.com/products/roll...on-battery-cap

snip

No, quite and that would be expected. The 'issue' is that you should
check the electrolyte levels more regularly so that they are above the
plates at all times, not just as you are about to recharge them? ;-(

"If low on electrolyte, immediately fill the battery with distilled or
de-ionized water. Tap water may be acceptable in some regions. Do not
fill to the correct level before charging as this could cause an
overflow during charging. Always top up to the desired level after
charging."

http://batteryuniversity.com/learn/a...d_acid_battery

Hadn't come across that point before, although I have seen small
motorcycle batteries with a sort of overflow pipe. On a Japanese bike
you are trying to get maximum capacity in minimum volume, so the plates
are going to go near the top. But on this battery which came from a
diesel car but curiously is identical to the battery on my old tractor
there's a good half an inch of space between the level marker and the
bottom of the cap threads. I agree that you might expect some change of
volume between discharged and fully charged but its not an effect I have
ever noticed on car batteries.

Shouldn't the same theory apply to any flooded lead acid battery
whatever it was to be used on. ;-)

snip

As an example, on the night of the big local firework display I got two
hours of light out of about 50 watts of CFL, and I'd estimate that I
have also had a similar amount of light out of the rest of the last charge.

Is that 50W 'equivalent of incandescent' (and so say 10W of electrical
load) or 50W of actual load?

Actual load. IIRC, four 11s and a 9, or something like that.

Ok.

Cheers, T i m

Recombination catalysts are very pricey, the chances of them being supplied in a car battery are near zero.


NT

On Sat, 18 Nov 2017 13:03:26 -0800 (PST), wrote:

snip

Recombination catalysts are very pricey, the chances of them being supplied in a car battery are near zero.


So, when did you last top up your car battery?

Cheers, T i m

On 18/11/2017 21:34, T i m wrote:
On Sat, 18 Nov 2017 13:03:26 -0800 (PST), wrote:

snip

Recombination catalysts are very pricey, the chances of them being supplied in a car battery are near zero.


So, when did you last top up your car battery?

That has been my point in this thread. You don't expect a good battery
to gas when charged by a well suitably controlled charger.

Batteries can go without topping up for years. Hence the OP's experience
is out of kilter with mine.

I can assure you it isn't due to recombination catalysts.

On Sat, 18 Nov 2017 21:52:30 +0000, Fredxxx wrote:

On 18/11/2017 21:34, T i m wrote:
On Sat, 18 Nov 2017 13:03:26 -0800 (PST), wrote:

snip

Recombination catalysts are very pricey, the chances of them being supplied in a car battery are near zero.


So, when did you last top up your car battery?

That has been my point in this thread. You don't expect a good battery
to gas when charged by a well suitably controlled charger.

I'm not sure that is true. I've just bought 3 traction / cyclic spec
'gel' batteries (not wet / flooded) that are VRLA and gas whilst being
charged during the balance phase (you can hear them doing so quite
clearly).

It is good that stationary flooded cells gas to some degree when in
the last phase of their charge to prevent electrolyte (and therefore
charge) 'stratification' as the rising bubbles help mix the
electrolyte.

Batteries can go without topping up for years. Hence the OP's experience
is out of kilter with mine.

I agree. My EV didn't have recombination cell caps and so did require
regular distilled water adding and when left unattended for a long
time, most of the cells dried out to some degree. ;-(

I can assure you it isn't due to recombination catalysts.

Cells do gas not only when charged but when being discharged and that
includes when they are self-discharging. If the OP's battery is only
25% of it's original capacity and whilst it is still functioning, I
wonder if it's self-discharging more than the other batteries he's
comparing it with? shrug

Cheers, T i m

On 18/11/2017 22:20, T i m wrote:
On Sat, 18 Nov 2017 21:52:30 +0000, Fredxxx wrote:

On 18/11/2017 21:34, T i m wrote:
On Sat, 18 Nov 2017 13:03:26 -0800 (PST), wrote:

snip

Recombination catalysts are very pricey, the chances of them being supplied in a car battery are near zero.


So, when did you last top up your car battery?

That has been my point in this thread. You don't expect a good battery
to gas when charged by a well suitably controlled charger.

I'm not sure that is true. I've just bought 3 traction / cyclic spec
'gel' batteries (not wet / flooded) that are VRLA and gas whilst being
charged during the balance phase (you can hear them doing so quite
clearly).

It is good that stationary flooded cells gas to some degree when in
the last phase of their charge to prevent electrolyte (and therefore
charge) 'stratification' as the rising bubbles help mix the
electrolyte.

Complex charge regimes usually have an equalisation charge phase where
the intention is to 'overcharge' the battery so it gasses, hopefully
undoing some of the sulfation and mixing the electrolyte. It's done as a
separate process to absorption and float charging.
Batteries can go without topping up for years. Hence the OP's experience
is out of kilter with mine.

I agree. My EV didn't have recombination cell caps and so did require
regular distilled water adding and when left unattended for a long
time, most of the cells dried out to some degree. ;-(

I can assure you it isn't due to recombination catalysts.

Cells do gas not only when charged but when being discharged and that
includes when they are self-discharging. If the OP's battery is only
25% of it's original capacity and whilst it is still functioning, I
wonder if it's self-discharging more than the other batteries he's
comparing it with? shrug

Given the quantities of water the OP says the battery has been
consuming, even a complete self-discharge wouldn't cause 50ml to
disappear from each cell.

On Sun, 19 Nov 2017 01:11:03 +0000, Fredxxx wrote:

snip

It is good that stationary flooded cells gas to some degree when in
the last phase of their charge to prevent electrolyte (and therefore
charge) 'stratification' as the rising bubbles help mix the
electrolyte.

Complex charge regimes usually have an equalisation charge phase where
the intention is to 'overcharge' the battery so it gasses,

As do the most basic transformer based chargers.

hopefully
undoing some of the sulfation

That would be a big *hope* IMHO.

and mixing the electrolyte.

Yes, that is a positive side effect of 'overcharge' gassing.

It's done as a
separate process to absorption and float charging.

Yes, if you break down the phases logically with say a 'Smart' charger
but still happens with a basic charger (to varying degrees, depending
on the terminal battery voltage and the charge / current and voltage
etc), during the end of the absorption phase (the last 10% of the
charge).

snip

Cells do gas not only when charged but when being discharged and that
includes when they are self-discharging. If the OP's battery is only
25% of it's original capacity and whilst it is still functioning, I
wonder if it's self-discharging more than the other batteries he's
comparing it with? shrug

Given the quantities of water the OP says the battery has been
consuming, even a complete self-discharge wouldn't cause 50ml to
disappear from each cell.

I agree. The 8 x Crompton 6V x 200Ah traction monoblocks I was running
in the EV would take that (each) and more if I left the checks for a
bit too long (weeks rather than days) but I'm not sure even they would
lose that (each) when the car was not being used. However, when left
for a couple of years unused, even these large and fairly new
(compared to the OP's battery) batteries lost enough electrolyte to
expose the plates. If I checked them again now, all the cells are
probably bone dry. ;-(

Now, that is either from evaporation or the plastic battery cases
being gas-permeable to some degree (as is much plastic) and it's (the
water) simply leaving as gas (H2O)?

Cheers, T i m

On Sat, 18 Nov 2017 01:56:26 GMT, Johnny B Good wrote:

I have a theory that by sacrificing some some 5 or 10 percent of usable
capacity by reducing the float charging voltage to 13.5v per car battery instead of the "standard 13.8v" normally used by APC UPSes, I might be
able to get a better than 5 year service life. However, I haven't had
the heart to put this to the test so it remains just a theory.

APC "Smart" UPS's do cook their batteries. I only have a little one
(750 VA) and it used to kill a pair of 12 V 7 AHr SLA's in 3 to 4
years.

The last failure was of the "What's that funny smell?" "Seems to be
under the desk" "Ouch the UPS is rather hot":

https://www.flickr.com/photos/allsorts-60/16591022171

I then reduced the charge voltage and fitted a fan. UPS now reports
around 30C internal temperature instead of the 40 odd before. This
was in Mar 2014, We've had a few short mains glitches recently that
the UPS covered, previously that sort of thing would have alerted me
to kanckered batteries. Guess I need to give it a real test though,
may be later.

--
Cheers
Dave.

In article ,
newshound wrote:
IIRC this was originally an 80 amp-hour battery and it certainly still
provides more than 10 AH at 12 volts, based on the lights that I run off
it. And it is usually powering a couple of PIR lights that also get
triggered through the night by cats, foxes, etc, so I suspect it's doing
better than that.

My posh tester tells me a lead acid needs to be replaced when the nominal
capacity drops by more than 20%. ;-)

--
*Sherlock Holmes never said "Elementary, my dear Watson" *

Dave Plowman London SW
To e-mail, change noise into sound.

On 19/11/2017 11:08, Dave Liquorice wrote:
On Sat, 18 Nov 2017 01:56:26 GMT, Johnny B Good wrote:

I have a theory that by sacrificing some some 5 or 10 percent of usable
capacity by reducing the float charging voltage to 13.5v per car battery instead of the "standard 13.8v" normally used by APC UPSes, I might be
able to get a better than 5 year service life. However, I haven't had
the heart to put this to the test so it remains just a theory.

APC "Smart" UPS's do cook their batteries. I only have a little one
(750 VA) and it used to kill a pair of 12 V 7 AHr SLA's in 3 to 4
years.

The last failure was of the "What's that funny smell?" "Seems to be
under the desk" "Ouch the UPS is rather hot":

https://www.flickr.com/photos/allsorts-60/16591022171

I then reduced the charge voltage and fitted a fan. UPS now reports
around 30C internal temperature instead of the 40 odd before. This
was in Mar 2014, We've had a few short mains glitches recently that
the UPS covered, previously that sort of thing would have alerted me
to kanckered batteries. Guess I need to give it a real test though,
may be later.

Voltage is everything in charging a Lead Acid battery. Also, the higher
the temperature the lower the ideal float charge voltage.

Anything more than 13.8V continuously applied is going to shorten the
life of the battery.

Dave Liquorice wrote:

APC "Smart" UPS's do cook their batteries.

They can but not always. I can't help feeling they would help
themselves if they ran the fan at low speed to increase airflow, even
when there wasn't a mains problem.

The last failure was of the "What's that funny smell?" "Seems to be
under the desk" "Ouch the UPS is rather hot":

https://www.flickr.com/photos/allsorts-60/16591022171

A couple of years ago I posted a very similar photo of a Yuasa Y7
battery bulging after being used in an APC UPS

http://adslpipe.co.uk/photos/APC_UPS_battery.jpg

However the Y7 range are designed as alarm panel batteries, they produce
NP7 batteries for UPS type applications.

I then reduced the charge voltage

I found the "secret" commands to adjust the float voltage (perhaps with
hints from you or someone else here) and set out to adjust mine, only to
find they were already bang-on.

and fitted a fan.

As noted above, mine has a fan, but only uses it when it's covering a
mains problem. Quite annoyingly it runs it for the daily spikes of a
couple of seconds around midnight when "something" at the substation
adjusts for over-voltage.

On Sun, 19 Nov 2017 12:31:09 +0000, Fredxxx wrote:

Voltage is everything in charging a Lead Acid battery. Also, the higher
the temperature the lower the ideal float charge voltage.

Some ought to tell APC. I dug out the datasheet for the batteries,
the charge voltage was way above what it should be for the
temperature of the batteries, for bulk rate let alone float!

Not that APC UPS chargers have bulk and float rates...

--
Cheers
Dave.

On 18/11/2017 21:52, Fredxxx wrote:
On 18/11/2017 21:34, T i m wrote:
On Sat, 18 Nov 2017 13:03:26 -0800 (PST), wrote:

snip

Recombination catalysts are very pricey, the chances of them being
supplied in a car battery are near zero.


So, when did you last top up your car battery?

That has been my point in this thread. You don't expect a good battery
to gas when charged by a well suitably controlled charger.

Batteries can go without topping up for years. Hence the OP's experience
is out of kilter with mine.

I can assure you it isn't due to recombination catalysts.


*My* point is that while I understand perfectly that overcharged
batteries will gas during (over) charging, mine appears to be losing
electrolyte while *discharging*.

On 19/11/2017 11:16, Dave Plowman (News) wrote:
In article ,
newshound wrote:
IIRC this was originally an 80 amp-hour battery and it certainly still
provides more than 10 AH at 12 volts, based on the lights that I run off
it. And it is usually powering a couple of PIR lights that also get
triggered through the night by cats, foxes, etc, so I suspect it's doing
better than that.

My posh tester tells me a lead acid needs to be replaced when the nominal
capacity drops by more than 20%. ;-)

And that might well be a reasonably criterion for an automotive battery,
especially measuring at normal temperatures since the performance drops
with temperature.

But this one is still doing its job, although it looks as though one
cell might now be shorted, since this one isn't gassing. Didn't have a
DVM to hand but will check the voltage tomorrow.

On Sun, 19 Nov 2017 11:08:18 +0000, Dave Liquorice wrote:

On Sat, 18 Nov 2017 01:56:26 GMT, Johnny B Good wrote:

I have a theory that by sacrificing some some 5 or 10 percent of usable
capacity by reducing the float charging voltage to 13.5v per car
battery instead of the "standard 13.8v" normally used by APC UPSes, I
might be able to get a better than 5 year service life. However, I
haven't had the heart to put this to the test so it remains just a
theory.

APC "Smart" UPS's do cook their batteries. I only have a little one (750
VA) and it used to kill a pair of 12 V 7 AHr SLA's in 3 to 4 years.

The last failure was of the "What's that funny smell?" "Seems to be
under the desk" "Ouch the UPS is rather hot":

https://www.flickr.com/photos/allsorts-60/16591022171

I then reduced the charge voltage and fitted a fan. UPS now reports
around 30C internal temperature instead of the 40 odd before. This was
in Mar 2014, We've had a few short mains glitches recently that the UPS
covered, previously that sort of thing would have alerted me to
knackered batteries. Guess I need to give it a real test though, may be
later.

JOOI, What did you reset the charging voltage to on that APC SmartUPS?
Presumably it would have originally been set to 27.6v. Did you throttle
it all the way back to 27.0v?

BTW, I've never seen APC batteries so badly cooked as that. More
typically ime, they may swell slightly in the beam, never developing a
noticeable hump on the top. That battery pack is in an even worse state
than the set of 3 NP7s that got cooked by my UPSonic600, an ancient pure
sinwave inverter type - it has a Honeywell "PAT" sticker with test dates
of December 1993 and 1994 stuck on the back panel!

None of my APC UPSes have been modern enough to be blessed by anything
other than a dumb charging circuit (voltage regulated to 13.8v per 6
cell's worth of battery pack). Similarly for that monster Upsonic600 with
its 3x12v7AH SLA 36v battery pack (a slide in tray, optionally filled
with two bank's worth of battery packs) and an ancient Emerson 30 with a
pair of 7AH SLAs.

I've long since retired the SmartUPS700 simply because of its
unconscionably high maintenance consumption of 20W (virtually none of
which goes into keeping the battery pack charged). I think I retired the
venerable Upsonic600 just prior to that when it started to cook its
second lot of batteries after just another 2 or 3 years of service.

The APC BackUPS500 that I bought brand new in the box at a radioham
rally some 15 years back is on its second (single) NP7. I haven't tested
that in anger since the initial half hour commissioning test of the 50
odd watts test load of my FreeNAS (now NAS4Free) box (left halted during
the POST to avoid FS corruption if the test had exhausted the UPS battery
before I could manually restore the mains supply). I've not really had a
chance to safely put it to the test during the past 4 or 5 years, so it's
anyone's guess as to the condition of the battery now.

I presume the battery is still be in good condition since the total
power consumption looks to be just the normal 3 watts in excess of the
base load of the NAS box. I keep a UK version of the Kill-A-Watt meter
permanently in line to monitor total consumption of UPS plus NAS box just
to keep an eye on this. The last time I finally got around to checking
the UPS out to discover the battery had failed, I'd been observing total
power consumption figures of 58 or more watts. The knackered UPS battery
proved to be the cause of the mysterious rise in energy consumption,
initially misattributed to the NAS box itself.

I suppose I aught to take the opportunity to properly test the battery
and to update the boot image file and pull the now finally redundant 5yo
3TB tiddler out of the box (I finally finished my 2 year "Convert mpg to
mkv to free up disk space" project just a week or two back). I think that
after some 3 years of uptime, interrupted by a fortnight's break just
over a year back, it's high time I did a spot of maintenance. I'll be
able to achieve three goals for this next planned downtime, boot image
update, UPS battery test and elimination of the retired HDD and its 7 or
8 watts of loading (should reduce the server idle load down from 51 to 45
watts or less, all three remaining drives spinning - I don't utilise any
spin down power saving).

Anyway, it isn't only APC who use the 13.8v SLA float charging standard,
it's pretty well every make of UPS. They don't care for extending the
battery life unduly by choosing a less corrosive 13.5 v when the higher
voltage offers the cheapest way to achieve the maximum autonomy from a
new set of batteries.

The one or two year warranties typically exclude the battery pack since
they treat it as a 'mere consumable' whose life depends on the number of
outages it may have had to deal with during the woefully short warranty
period. As long as the batteries can survive the initial one or two years
without obvious signs of failure after handling maybe just one or two
short lived outages, that's good enough for the manufacturers who are
only too keen to supply replacement packs at premium prices every 3 to 5
years.

The modern UPSes might include improved SLA charge management algorithms
these days, I just don't know whether any of the manufacturers are
looking to gain a marketing advantage over the competition in regard of
battery pack service life. One way to improve battery pack life would be
to recharge to 13.8v then drop back to 13.5v with a monthly boost back to
13.8v for say 6 to 12 hours at a time.

I've kept a spare 12A SLA in good enough condition by solar panel
charging alone for just a week or so per year to jump start my wife's Y
reg 1.6 litre automatic Astra a year or two after buying the battery 2nd
hand from a flea market stall some 5 or 6 years ago. It proved to be
nearly flat when I got it home. Just 11.99v open circuit on my own DMMs
as opposed to some 12.5v on a borrowed meter from another stall holder at
the flea market - presumably, a meter with a low battery warning
indicator I'd overlooked in my haste to get a reading before parting with
my fiver.

I've checked it just now and I'm seeing a reading of 12.65v some 6
months after its summertime solar charging stint. A brief test with an H3
55W halogen headlamp capsule shows it can still provide power (it's not a
case of high resistance normal voltage failure symptoms that these
batteries can land up developing). Normally, I'd see post fully charged
resting voltages around the 12.78v mark for most of the remaining 11 1/2
months of the year that it sits on my office window ledge in splendid
isolation awaiting its next annual refreshing charge.

The fact that a charging regime of just once per year to 13.8v (peaking
to 14.6v for short periods of an hour or so) has been enough to keep this
battery in good condition, rather reinforces my theory that 13.5v is more
than sufficient to keep the battery from sulphating at, presumably, some
small reduction in effective usable capacity from a float charge state of
13.8v.

The choice of voltage level for continuous float charging of a LA
battery is a compromise between a lower limit that defines an acceptable
sulphation rate and an upper limit that defines an acceptable corrosion
rate (along with water loss). I've no doubt that the float charge voltage
also effects the maximum usable capacity as well so it's not too
surprising that the maximum voltage is chosen to 'improve autonomy
bragging rights' by the UPS manufacturers at the expense of a life
shortened to a mere 2 or 3 years when it becomes the customer's problem
(and their chance to sell premium priced battery packs - a win, win for
the manufacturers - the inkjet manufacturers weren't the first to profit
from the consumables market, just the first to do so so outrageously).

--
Johnny B Good