old tractor, 2 x 12v biggish batteries linked in parallel provide
the power to start.

Only used for fetching haylage once a week so batteries often
don't start it the next time....

Is it OK to just charge the pair of batteries by clipping on a
battery charger, without disconnecting the interconnecting
wiring?

Or is it necessary or advisable (and why please) to electrically
isolate each and charge one at a time?

For longer term would a solar trickle charger be worthwhile?

TIA
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On 13/12/2016 18:14, jim wrote:

old tractor, 2 x 12v biggish batteries linked in parallel provide
the power to start.

Only used for fetching haylage once a week so batteries often
don't start it the next time....

Is it OK to just charge the pair of batteries by clipping on a
battery charger, without disconnecting the interconnecting
wiring?

Or is it necessary or advisable (and why please) to electrically
isolate each and charge one at a time?

For longer term would a solar trickle charger be worthwhile?

TIA

Assuming that they are in parallel and it isn't a 24V vehicle...

They get charged and discharged together by the vehicle, so you might as
well do the same with an external charger. I suppose you could check
periodically whether there's an imbalance if you were bothered, but
really once you suspect a battery is knackered replace them both. Stands
to reason the new ones should be identical.

Bill

Bill Wright Wrote in message:
On 13/12/2016 18:14, jim wrote:

old tractor, 2 x 12v biggish batteries linked in parallel provide
the power to start.

Only used for fetching haylage once a week so batteries often
don't start it the next time....

Is it OK to just charge the pair of batteries by clipping on a
battery charger, without disconnecting the interconnecting
wiring?

Or is it necessary or advisable (and why please) to electrically
isolate each and charge one at a time?

For longer term would a solar trickle charger be worthwhile?

TIA

Assuming that they are in parallel and it isn't a 24V vehicle...


Lead from +ve1 to +ve2 and 2x -ves commoned to the metalwork.


They get charged and discharged together by the vehicle, so you might as
well do the same with an external charger. I suppose you could check
periodically whether there's an imbalance if you were bothered, but
really once you suspect a battery is knackered replace them both. Stands
to reason the new ones should be identical.

Bill

Makes sense!
Thanks
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On 13/12/2016 18:46, jim wrote:

Lead from +ve1 to +ve2 and 2x -ves commoned to the metalwork.


They get charged and discharged together by the vehicle, so you might as
well do the same with an external charger. I suppose you could check
periodically whether there's an imbalance if you were bothered, but
really once you suspect a battery is knackered replace them both. Stands
to reason the new ones should be identical.

Bill

Makes sense!
Thanks

I suppose it's important that any leads and connectors that aren't
common to both batteries are perfectly clean, to avoid a situation where
one battery is a 'passenger'.

I mean the battery terminals, mainly.

Bill

On 12/13/2016 6:14 PM, jim wrote:

old tractor, 2 x 12v biggish batteries linked in parallel provide
the power to start.

Only used for fetching haylage once a week so batteries often
don't start it the next time....

Is it OK to just charge the pair of batteries by clipping on a
battery charger, without disconnecting the interconnecting
wiring?

Or is it necessary or advisable (and why please) to electrically
isolate each and charge one at a time?

For longer term would a solar trickle charger be worthwhile?

TIA

With this arrangement, isn't there a danger that if one battery
deteriorates (e.g. a cell shorting out) it will knacker the good one?

As others have said, since the generator charges them like this there's
no reason not to do the same with an external charger.

Was this the original arrangement or is it a later bodge? I think if it
was mine I would fit a "quick detach" connector to each of the positives
so that I could monitor the batteries separately. And perhaps just start
on one?

I have these on a couple of my "yard" vehicles because they seem to have
some discharge current when left connected.

http://www.ebay.co.uk/itm/Battery-Cl...AOSwo3pWenR l

On 13/12/2016 22:41, newshound wrote:

With this arrangement, isn't there a danger that if one battery
deteriorates (e.g. a cell shorting out) it will knacker the good one?

Yes. But if they're the same age and type you wouldn't worry about which
one had failed, you'd simply change both.

I wonder if the batteries are knackered anyway, or at least well past
their best. After all, a decent battery of the correct size should start
the engine without further help.

In the days of my youth a fellow student who had an Austin 1100 (I
think) was having starting problems. Clearly the battery was knackered.
As it happened I also had a knackered battery. I went to the motorists
discount and bought the cheapest one I could find (I think it was £7).
My friend wanted to try my old battery on his car. It was somewhat
better than his in that it would turn the engine over for a few seconds,
but it still wouldn't start the car. He then tried both batteries in
parallel, which of course didn't work. He then tried the batteries in
series. The starter motor turned quite well for a few seconds but then
stopped. All this in the students' car park when we should have been
attending a lecture. For some weeks he made sure to always park at the
top of an incline, but then one day he was distracted by a spider
lowering itself down from the car's ceiling, and he hit a wall. That was
the end of that. He lived but the car didn't.

The seven quid battery lasted less than a year, but I never got my money
back. I didn't bother trying.

Bill

Bill Wright wrote
newshound wrote

With this arrangement, isn't there a danger that if one battery
deteriorates (e.g. a cell shorting out) it will knacker the good one?

Yes. But if they're the same age and type you wouldn't worry about which
one had failed, you'd simply change both.

I wonder if the batteries are knackered anyway, or at least well past
their best. After all, a decent battery of the correct size should start
the engine without further help.

It isnt a car, it’s a piece of farm machinery that doesn’t get used a lot.

On Tuesday, December 13, 2016 at 6:14:13 PM UTC, jim wrote:
old tractor, 2 x 12v biggish batteries linked in parallel provide
the power to start.

Only used for fetching haylage once a week so batteries often
don't start it the next time....

Is it OK to just charge the pair of batteries by clipping on a
battery charger, without disconnecting the interconnecting
wiring?

Or is it necessary or advisable (and why please) to electrically
isolate each and charge one at a time?

For longer term would a solar trickle charger be worthwhile?



This is the typical situation in narrowboats, i.e. two or more batteries strapped in parallel and charged that way both by the alternator (when engine running) or by battery charger.

Take care with solar trickle charging over long periods. I have seen batteries wrecked by this. Once the batteries are charged the trickle goes on electrolysing the water (gassing) and eventually the plates get exposed and damaged.

Robert

Personally I've found nothing but grief from car batteries in this mode.
Say one battery has a dodgy cell, the other battery then charges the duff
one until neither are very good.
If it were a low power use I'd say isolate them by diodes and charge one at
a time but in this case, either get a battery capable of starting the
vehicle on its own, make sure but batteries are switchable and keep both
charged and use them in rotation.


Incidentally this using cells in parallel goes even more so for other
rechargeable types.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"jim" k wrote in message
o.uk...
old tractor, 2 x 12v biggish batteries linked in parallel provide
the power to start.

Only used for fetching haylage once a week so batteries often
don't start it the next time....

Is it OK to just charge the pair of batteries by clipping on a
battery charger, without disconnecting the interconnecting
wiring?

Or is it necessary or advisable (and why please) to electrically
isolate each and charge one at a time?

For longer term would a solar trickle charger be worthwhile?

TIA
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

Brian Gaff has brought this to us :
If it were a low power use I'd say isolate them by diodes and charge one at a
time but in this case, either get a battery capable of starting the vehicle
on its own, make sure but batteries are switchable and keep both charged and
use them in rotation.

You cannot isolate batteries via diodes, because it would create a
difference of 0.7v due to the voltage lost across the diode. 0.7v is a
lot of difference in battery voltage terms, much more than the
difference between a fully charged and a flat battery.

On 14/12/2016 04:57, Rod Speed wrote:
Bill Wright wrote
newshound wrote

With this arrangement, isn't there a danger that if one battery
deteriorates (e.g. a cell shorting out) it will knacker the good one?

Yes. But if they're the same age and type you wouldn't worry about
which one had failed, you'd simply change both.

I wonder if the batteries are knackered anyway, or at least well past
their best. After all, a decent battery of the correct size should
start the engine without further help.

It isnt a car, it’s a piece of farm machinery that doesn’t get used a lot.

Yes you said. It doesn't really matter. If it was designed to start on
one battery that should be all it needs. If one battery won't produce
enough current to turn the engine over fast enough then there's
something wrong. The battery, the cables, the starter, or the engine.

If it doesn't run for long enough to recharge the battery after starting
then yes, you'll need some auxiliary charging. The little solar chargers
aren't much use. The bigger ones are better. Unless the vehicle is in a
barn!

Leakage is also an issue, especially if the electrics are damp. I have
leakage on the motorhome of 0.001 to 0.002A in winter, which would be
significant if I didn't use the vehicle for several months.

Bill

On 14/12/2016 09:03, RobertL wrote:


Take care with solar trickle charging over long periods.

I have seen batteries wrecked by this. Once the batteries

are charged the trickle goes on electrolysing the water (gassing) and eventually the plates get exposed and damaged.

Yes, that's with a proper big solar panel. The little ones (about a foot
by 6") won't do that.

Bill

On 14/12/2016 10:39, Brian Gaff wrote:
Personally I've found nothing but grief from car batteries in this mode.
Say one battery has a dodgy cell, the other battery then charges the duff
one until neither are very good.
If it were a low power use I'd say isolate them by diodes

Better to use relays.

Bill

In article , Harry Bloomfield
wrote:
Brian Gaff has brought this to us :
If it were a low power use I'd say isolate them by diodes and charge
one at a time but in this case, either get a battery capable of
starting the vehicle on its own, make sure but batteries are
switchable and keep both charged and use them in rotation.

You cannot isolate batteries via diodes, because it would create a
difference of 0.7v due to the voltage lost across the diode. 0.7v is a
lot of difference in battery voltage terms, much more than the
difference between a fully charged and a flat battery.


You certainly can isolate batteries via diodes. Lucas used to make a unit
-about the same size as an ignition coil specifially for this purpose. Our
tecnical survey vehicles used them in the 70's and '80s. After then, a
hefty relay, which closed when the alternator was producing enough volts
was used.

--
from KT24 in Surrey, England

"Bill Wright" wrote in message
news
On 14/12/2016 04:57, Rod Speed wrote:
Bill Wright wrote
newshound wrote

With this arrangement, isn't there a danger that if one battery
deteriorates (e.g. a cell shorting out) it will knacker the good one?

Yes. But if they're the same age and type you wouldn't worry about
which one had failed, you'd simply change both.

I wonder if the batteries are knackered anyway, or at least well past
their best. After all, a decent battery of the correct size should
start the engine without further help.

It isnt a car, it’s a piece of farm machinery that doesn’t get used a
lot.

Yes you said. It doesn't really matter.

Corse it does.

If it was designed to start on one battery that should be all it needs.

And if it never was designed to start on one battery, it wouldn't be.

If one battery won't produce enough current to turn the engine over fast
enough

You don’t know that is the problem.

then there's something wrong.

Not if was always designed to need two batterys in parallel to start it.

The battery, the cables, the starter, or the engine.

You don’t know that there is any fault at all.

If it doesn't run for long enough to recharge the battery after starting

That does appear to be the problem.

then yes, you'll need some auxiliary charging. The little solar chargers
aren't much use. The bigger ones are better. Unless the vehicle is in a
barn!

In which case it should be possible to plug it in in
the barn to allow it to be charged when in there.

Leakage is also an issue, especially if the electrics are damp. I have
leakage on the motorhome of 0.001 to 0.002A in winter, which would be
significant if I didn't use the vehicle for several months.

charles laid this down on his screen :
You certainly can isolate batteries via diodes. Lucas used to make a unit
-about the same size as an ignition coil specifially for this purpose. Our
tecnical survey vehicles used them in the 70's and '80s. After then, a
hefty relay, which closed when the alternator was producing enough volts
was used.

Because they realised that diodes just did not and could not work?

The only way you can make diodes work effectively, is by increasing the
input voltage by 0.6 to 0.7 volts to take care of the forward voltage
lost across the junction.

Bill Wright formulated the question :
Better to use relays.

The ONLY effective method.

In article ,
Harry Bloomfield wrote:
charles laid this down on his screen :
You certainly can isolate batteries via diodes. Lucas used to make a
unit -about the same size as an ignition coil specifially for this
purpose. Our tecnical survey vehicles used them in the 70's and '80s.
After then, a hefty relay, which closed when the alternator was
producing enough volts was used.

Because they realised that diodes just did not and could not work?

They did work - we used them for at least 15 years, running technical
equipment off the second battery.

The only way you can make diodes work effectively, is by increasing the
input voltage by 0.6 to 0.7 volts to take care of the forward voltage
lost across the junction.

the relay was better.

--
from KT24 in Surrey, England

Harry Bloomfield wrote:
The only way you can make diodes work effectively, is by increasing the
input voltage by 0.6 to 0.7 volts to take care of the forward voltage
lost across the junction.

Well it depends. If you don't need starting current you can get the forward
voltage down a fair bit:
http://uk.farnell.com/vishay/vs-80cp...247/dp/1013352

That would be acceptable to run equipment off without the 320mV forward
voltage being too bad. But obviously switching with relays would be more
efficient - you don't lose several watts in the diode. Use diodes to power
the relays.

If you need hundreds of amps then you are in the 600mV territory for voltage
drop.

Theo

After serious thinking charles wrote :
They did work - we used them for at least 15 years, running technical
equipment off the second battery.

Perhaps it would, assuming the equipment would be satisfied to work
from a partially charged battery.


The only way you can make diodes work effectively, is by increasing the
input voltage by 0.6 to 0.7 volts to take care of the forward voltage
lost across the junction.

the relay was better.

Of course the relay was much better, the battery would receive a full
charge and the equipment the full voltage.

In article ,
Harry Bloomfield wrote:
After serious thinking charles wrote :
They did work - we used them for at least 15 years, running technical
equipment off the second battery.

Perhaps it would, assuming the equipment would be satisfied to work
from a partially charged battery.

Anything car related is designed to work over a wide range of voltage -
say 9-14. The range between starting on a cold day to battery on charge.


The only way you can make diodes work effectively, is by increasing
the input voltage by 0.6 to 0.7 volts to take care of the forward
voltage lost across the junction.

the relay was better.

Of course the relay was much better, the battery would receive a full
charge and the equipment the full voltage.

Apart from starter use, I'd use two diodes to prevent either battery
discharging the other when not on charge. And relays to bypass them for
charging.

But in practice simply fit a larger battery. I've never known any 12v
vehicle that needed two 12v ones. To increase the capacity beyond one 12v
use two large 6v in series. Same as is done with 24v.

--
*The man who fell into an upholstery machine is fully recovered*

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

On 14/12/2016 16:14, Rod Speed wrote:

It isnt a car, it’s a piece of farm machinery that doesn’t get used a
lot.

Yes you said. It doesn't really matter.

Corse it does.
No it doesn't. I have a car that doesn't get used a lot. I have a willy
that doesn't get used a lot and when I do want to use it it often won't
start.


If it was designed to start on one battery that should be all it needs.

And if it never was designed to start on one battery, it wouldn't be.

Agreed, but very few things have two batteries. Usually they have one,
sized appropriately. There are as we have discussed possible problems
with two smaller batteries.


If one battery won't produce enough current to turn the engine over
fast enough

You don’t know that is the problem.
He said he was having trouble starting it. If the machine was turning
over qiuickly but not starting he wouldn't suspect the battery.


then there's something wrong.

Not if was always designed to need two batterys in parallel to start it.
Agreed but that's very unusual as I said. I was assuming the OP would
have the intelligence to discount my remark if it was the case.


The battery, the cables, the starter, or the engine.

You don’t know that there is any fault at all.
I do, the guy said it wouldn't start. Therefore there's a fault. Things
are supposed to start. Shall I tell you about my willy again?


If it doesn't run for long enough to recharge the battery after starting

That does appear to be the problem.

then yes, you'll need some auxiliary charging. The little solar
chargers aren't much use. The bigger ones are better. Unless the
vehicle is in a barn!

In which case it should be possible to plug it in in
the barn to allow it to be charged when in there.
Not all barns have an electric supply. Barns that are detached from
habitation or remote from it usually don't. Why did you say that anyway?
You're just sniping without a target. Got out of bed the wrong side?

Bill

On 14/12/2016 16:01, charles wrote:

You certainly can isolate batteries via diodes. Lucas used to make a unit
-about the same size as an ignition coil specifially for this purpose. Our
tecnical survey vehicles used them in the 70's and '80s. After then, a
hefty relay, which closed when the alternator was producing enough volts
was used.

You can isolate them, but the voltage drop greatly reduces the charge
rate, and it will taper to zero before the battery is anything like
fully charged.

Bill

On 14/12/2016 21:36, charles wrote:
In article ,
Harry Bloomfield wrote:
charles laid this down on his screen :
You certainly can isolate batteries via diodes. Lucas used to make a
unit -about the same size as an ignition coil specifially for this
purpose. Our tecnical survey vehicles used them in the 70's and '80s.
After then, a hefty relay, which closed when the alternator was
producing enough volts was used.

Because they realised that diodes just did not and could not work?

They did work - we used them for at least 15 years, running technical
equipment off the second battery.

Yes because there was a relay that operated when the alternator was
working. That would be a voltage sensing relay, or if this was years ago
it would work from the ignition warning light circuit.

Bill

In article ,
Bill Wright wrote:
On 14/12/2016 21:36, charles wrote:
In article ,
Harry Bloomfield wrote:
charles laid this down on his screen :
You certainly can isolate batteries via diodes. Lucas used to make a
unit -about the same size as an ignition coil specifially for this
purpose. Our tecnical survey vehicles used them in the 70's and '80s.
After then, a hefty relay, which closed when the alternator was
producing enough volts was used.

Because they realised that diodes just did not and could not work?

They did work - we used them for at least 15 years, running technical
equipment off the second battery.

Yes because there was a relay that operated when the alternator was
working. That would be a voltage sensing relay, or if this was years ago
it would work from the ignition warning light circuit.

Bill

No we used diodes without the relay. later we just used the relay. Never
both together,

--
from KT24 in Surrey, England

charles brought next idea :
No we used diodes without the relay. later we just used the relay. Never
both together,

I cannot recall the full details, but...

I once devised a scheme which did use diodes on a car. Charging was via
diodes, to two batteries. I had set the generator regulator to around
1v higher to over come the diode forward loss.

Bill Wright wrote
Rod Speed wrote

It isnt a car, it’s a piece of farm machinery that doesn’t get used a
lot.

Yes you said. It doesn't really matter.

Corse it does.

No it doesn't.

Corse it does.

I have a car that doesn't get used a lot. I have a willy that doesn't get
used a lot and when I do want to use it it often won't start.

I was talking about why it has two batterys in parallel,
not what happens with stuff that isnt used a lot.

If it was designed to start on one battery that should be all it needs.

And if it never was designed to start on one battery, it wouldn't be.

Agreed, but very few things have two batteries.

But that piece of farm machinery may be one of them.

Usually they have one, sized appropriately. There are as we have discussed
possible problems with two smaller batteries.

Clearly it has a pair of paralleled batterys for a reason.

If one battery won't produce enough current to turn the engine over fast
enough

You don’t know that is the problem.

He said he was having trouble starting it.

But that may not be due to not be due to not
being able to turn the engine over fast enough.

If the machine was turning over qiuickly but not starting he wouldn't
suspect the battery.

Duh.

then there's something wrong.

Not if was always designed to need two batterys in parallel to start it.

Agreed but that's very unusual as I said.

But is seen WITH SOME FARM MACHINERY.

I was assuming the OP would have the intelligence to discount my remark if
it was the case.

He may well do that because you went on about
cars and he has a piece of FARM MACHINERY.

The battery, the cables, the starter, or the engine.

You don’t know that there is any fault at all.

I do, the guy said it wouldn't start. Therefore there's a fault.

It may just be that the battery doesn’t get charged enough
with the small amount of use it gets. He was asking about
how to charge the battery and he may well have decided
that that is the problem, it isnt getting fully charged after
having been used to start the FARM MACHINERY.

Things are supposed to start.

But if they arent used for long enough after they have
been started, the batterys may not be fully charged
and that may well be why he asked about how to
charge them other than by running the machine
for longer than it is used for.

Shall I tell you about my willy again?

No point, it was always irrelevant to his situation.

If it doesn't run for long enough to recharge the battery after starting

That does appear to be the problem.

then yes, you'll need some auxiliary charging. The little solar chargers
aren't much use. The bigger ones are better. Unless the vehicle is in a
barn!

In which case it should be possible to plug it in in
the barn to allow it to be charged when in there.

Not all barns have an electric supply.

I meant plug the bigger solar charger
into the machine when it is in the barn.

Barns that are detached from habitation or remote from it usually don't.
Why did you say that anyway?

Because it is one obvious way to have a bigger solar
charger charge the batterys when it is in the barn.
The bigger solar charger would obviously be outside
the barn with some wire to the machine inside the barn.

You're just sniping without a target.

Wrong. You just didn’t understand what I was talking
about plugging in. I didn’t mean plug in the mains,
I mean plug in the bigger solar charger.

Got out of bed the wrong side?

You're projecting now.

In message , jim
writes
But in practice simply fit a larger battery. I've never known any 12v
vehicle that needed two 12v ones.


Eastern bloc origin farm machinery...

Toyota Hilux K reg pickup 2.4L NA engine.

Cold winters, 5 litre diesel engine, 24v starter system = 50 %
amperage =easier wiring; 12v for the rest.

I think! :-)


--
Tim Lamb

"Dave Plowman (News)" Wrote in message:
In article ,
Harry Bloomfield wrote:
After serious thinking charles wrote :
They did work - we used them for at least 15 years, running technical
equipment off the second battery.

Perhaps it would, assuming the equipment would be satisfied to work
from a partially charged battery.

Anything car related is designed to work over a wide range of voltage -
say 9-14. The range between starting on a cold day to battery on charge.


The only way you can make diodes work effectively, is by increasing
the input voltage by 0.6 to 0.7 volts to take care of the forward
voltage lost across the junction.

the relay was better.

Of course the relay was much better, the battery would receive a full
charge and the equipment the full voltage.

Apart from starter use, I'd use two diodes to prevent either battery
discharging the other when not on charge. And relays to bypass them for
charging.

But in practice simply fit a larger battery. I've never known any 12v
vehicle that needed two 12v ones.


Eastern bloc origin farm machinery...

Cold winters, 5 litre diesel engine, 24v starter system = 50 %
amperage =easier wiring; 12v for the rest.

I think! :-)

--
Jim K