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Default OT: Car battery volt drop

In article ,
Fredxx wrote:
On 23/04/2021 13:43, Dave Plowman (News) wrote:
In article ,
williamwright wrote:
On 20/04/2021 20:02, Cliff Topp wrote:
All modern cars will have an amount of quiescent current draw to
power things like the alarm, the clock, the radio presets and so on
when the car is parked up and switched off. I've seen it written
somewhere that around 50mA can be considered 'normal'.

My question is - if the quiescent current draw is 50mA (0.05A), how
do I calculate voltage drop per hour?

For instance, if I park the car up at 10pm and the battery is
showing 12.5V, with a 50mA draw overnight what will the voltage be
at, say, 9am?


Couldn't the manufacturers fit a separate small battery dedicated to
supplying the quiescent items? One that would last maybe ten days.
With a user option to decide whether it should steal power from the
main battery when it became depleted?


Not too many would be keen on a car which still sort of starts, but
has to be taken to a garage to have all the things that rely on a
memory reset? Nor would it be a small battery. Up to 50 mA is a common
quiescent drain. Work out the size of battery needed to supply that
for any length of time.

If you know the car is not going to be used for some time, disconnect
the battery. At least then you won't need to buy a new one when you
eventually want to use it.


The last Transit I owned had two lead acid batteries of equal size.
During cranking and running they were connected together. At other times
one was isolated from any gizzmos and so zero drain.


I guess that is one solution to the problem.


So effectively a larger battery. That is one solution, but an expensive
one. And some will still leave it long enough for them to go flat.

--
*Nothing is foolproof to a sufficiently talented fool*

Dave Plowman London SW
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Default OT: Car battery volt drop

On 24/04/2021 00:27, Dave Plowman (News) wrote:
In article ,
Fredxx wrote:
On 23/04/2021 13:44, Dave Plowman (News) wrote:
In article ,
Fredxx wrote:
At 50mA that would be less than the self discharge rate of a lead acid
battery.

Not so. A lead acid in good condition has a very low self discharge
rate.


More than a 1,000 hours?


Yes.

A pal has a place in Spain. In better days goes there for at least 2
months at a time, leaving a car here. With the battery left connected,
totally flat on return. And toast. Disconnected, it will start the car
after re-connecting.


I thought the self-discharge rate was quite high but you're spot on, as
per usual.

This gives a self-discharge rate of 40% per year, I did see another
article that said 5% per month, but give or take they're both in the
same ball-park.

https://batteryuniversity.com/learn/...n_modern_times

Apart from a remote locking receiver being active I really don't see the
need for a current draw from anything else.

I would propose it would be cheaper to fix the current drain issues than
the cost of a second battery.

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Default OT: Car battery volt drop

On 24/04/2021 00:29, Dave Plowman (News) wrote:
In article ,
Fredxx wrote:
On 23/04/2021 13:43, Dave Plowman (News) wrote:
In article ,
williamwright wrote:
On 20/04/2021 20:02, Cliff Topp wrote:
All modern cars will have an amount of quiescent current draw to
power things like the alarm, the clock, the radio presets and so on
when the car is parked up and switched off. I've seen it written
somewhere that around 50mA can be considered 'normal'.

My question is - if the quiescent current draw is 50mA (0.05A), how
do I calculate voltage drop per hour?

For instance, if I park the car up at 10pm and the battery is
showing 12.5V, with a 50mA draw overnight what will the voltage be
at, say, 9am?

Couldn't the manufacturers fit a separate small battery dedicated to
supplying the quiescent items? One that would last maybe ten days.
With a user option to decide whether it should steal power from the
main battery when it became depleted?

Not too many would be keen on a car which still sort of starts, but
has to be taken to a garage to have all the things that rely on a
memory reset? Nor would it be a small battery. Up to 50 mA is a common
quiescent drain. Work out the size of battery needed to supply that
for any length of time.

If you know the car is not going to be used for some time, disconnect
the battery. At least then you won't need to buy a new one when you
eventually want to use it.


The last Transit I owned had two lead acid batteries of equal size.
During cranking and running they were connected together. At other times
one was isolated from any gizzmos and so zero drain.


I guess that is one solution to the problem.


So effectively a larger battery. That is one solution, but an expensive
one. And some will still leave it long enough for them to go flat.



In this case only one of these batteries would be flat. As soon as the
ignition switch is turned the two batteries are connected. I dread to
think the magnitude of current flow in the first few seconds.

Any flattened lead acid battery is going to be toast, or severely damaged.

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Default OT: Car battery volt drop

In article ,
Fredxx wrote:
On 24/04/2021 00:27, Dave Plowman (News) wrote:
In article ,
Fredxx wrote:
On 23/04/2021 13:44, Dave Plowman (News) wrote:
In article ,
Fredxx wrote:
At 50mA that would be less than the self discharge rate of a lead acid
battery.

Not so. A lead acid in good condition has a very low self discharge
rate.


More than a 1,000 hours?


Yes.

A pal has a place in Spain. In better days goes there for at least 2
months at a time, leaving a car here. With the battery left connected,
totally flat on return. And toast. Disconnected, it will start the car
after re-connecting.


I thought the self-discharge rate was quite high but you're spot on, as
per usual.


Just experience of them.

This gives a self-discharge rate of 40% per year, I did see another
article that said 5% per month, but give or take they're both in the
same ball-park.

https://batteryuniversity.com/learn/...n_modern_times


At one time new batteries were dry stored. When you bought one, they'd add
the acid. Not so now. Yet most would expect a new battery from Halfords
etc to start their car right away, without charging. So they must have low
self discharge. As not even Halfords will turn over their stock every
couple of weeks.

Apart from a remote locking receiver being active I really don't see the
need for a current draw from anything else.


Immobiliser? Radio memory? I'm sure the makers of expensive cars would do
everything they could to reduce quiescent load. It's not a good advert if
the car won't start after being left at an airport carpark while on
holiday.

I would propose it would be cheaper to fix the current drain issues than
the cost of a second battery.


I really don't see an answer to it with modern cars. And I'm sure many
very clever engineers have given it much thought.

--
*He's not dead - he's electroencephalographically challenged

Dave Plowman London SW
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Default OT: Car battery volt drop

On Fri, 23 Apr 2021 19:00:40 +0100, Fredxx wrote:

On 23/04/2021 13:44, Dave Plowman (News) wrote:
In article ,
Fredxx wrote:
At 50mA that would be less than the self discharge rate of a lead acid
battery.


Not so. A lead acid in good condition has a very low self discharge
rate.


More than a 1,000 hours?


How about more than 8760 hours?

A flea market purchase of a 2nd hand 12AH SLA I'd purchased for a fiver
(after checking the voltage was at least above the 12v mark on a borrowed
DMM) some five or six years ago. It was only when I retested the open
circuit voltage with my own DMMs on my return from the flea market that I
saw it was actually just below the 12v mark. I guess the cheap DMM I'd
borrowed either wasn't blessed with a low battery indicator or else I'd
simply not spotted whatever low battery warning symbol it may have
possessed.

Even now, it still in good condition (12.87v rest voltage reading about
a week or two after charging it up to 13.8v with my bench supply.

At that time, I did not have an SLA capable charger (or variable bench
supply) to safely charge it so used a pair of 1.2Wpk solar panels hung
out of the office window to take advantage of the summer sunshine. I
checked the voltage daily until it just topped the 13.8v mark about ten
to 14 days later. Checking the resting voltage the next and subsequent
days showed a 12.85v reading which over the months, until the next summer
solar charging season came around, dropped to 12.75v.

It did get used as a test voltage source for brief periods, often just
to check it could still produce amps with very little sag using a 50W
halogen headlamp capsule bulb (I wasn't planning on using it as a starter
battery).

However, after two such summer charging seasons one winter's evening, I
used it to jump start a 1.6l automatic whose battery had let me down
outside of our local chippy. It was my own fault, I knew the battery was
on its last legs but had still waited, engine off, with the parking
lights on for SWMBI to return from the chippy just 10 or 15 minutes
later, in spite of the street lighting allowing me to switch the lights
off to avoid just such a situation. Being an automatic, bump starting
just wasn't an option

I was rather surprised that a 2nd hand 12AH SLA purchased 2 1/2 years
earlier and only ever charged up twice with a couple of 1.2Wpk solar
panels could crank a 1.6l petrol engine into life so easily as it did
some six months after it had last been charged up.

I learnt a valuable lesson that evening, namely to reduce the float
charging voltage from the 2.133v per cell typically set by default with
UPSes down to the less abusive 2.1v value if you want your very expensive
"consumable" to last more than just a lousy two or three years (assuming
few to no brief mains outages in that time and that the automated weekly
battery test feature is also disabled).



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On 25/04/2021 05:47, Johnny B Good wrote:
On Fri, 23 Apr 2021 19:00:40 +0100, Fredxx wrote:

On 23/04/2021 13:44, Dave Plowman (News) wrote:
In article ,
Fredxx wrote:
At 50mA that would be less than the self discharge rate of a lead acid
battery.

Not so. A lead acid in good condition has a very low self discharge
rate.


More than a 1,000 hours?


How about more than 8760 hours?

A flea market purchase of a 2nd hand 12AH SLA I'd purchased for a fiver
(after checking the voltage was at least above the 12v mark on a borrowed
DMM) some five or six years ago. It was only when I retested the open
circuit voltage with my own DMMs on my return from the flea market that I
saw it was actually just below the 12v mark. I guess the cheap DMM I'd
borrowed either wasn't blessed with a low battery indicator or else I'd
simply not spotted whatever low battery warning symbol it may have
possessed.

Even now, it still in good condition (12.87v rest voltage reading about
a week or two after charging it up to 13.8v with my bench supply.

At that time, I did not have an SLA capable charger (or variable bench
supply) to safely charge it so used a pair of 1.2Wpk solar panels hung
out of the office window to take advantage of the summer sunshine. I
checked the voltage daily until it just topped the 13.8v mark about ten
to 14 days later. Checking the resting voltage the next and subsequent
days showed a 12.85v reading which over the months, until the next summer
solar charging season came around, dropped to 12.75v.

It did get used as a test voltage source for brief periods, often just
to check it could still produce amps with very little sag using a 50W
halogen headlamp capsule bulb (I wasn't planning on using it as a starter
battery).

However, after two such summer charging seasons one winter's evening, I
used it to jump start a 1.6l automatic whose battery had let me down
outside of our local chippy. It was my own fault, I knew the battery was
on its last legs but had still waited, engine off, with the parking
lights on for SWMBI to return from the chippy just 10 or 15 minutes
later, in spite of the street lighting allowing me to switch the lights
off to avoid just such a situation. Being an automatic, bump starting
just wasn't an option

I was rather surprised that a 2nd hand 12AH SLA purchased 2 1/2 years
earlier and only ever charged up twice with a couple of 1.2Wpk solar
panels could crank a 1.6l petrol engine into life so easily as it did
some six months after it had last been charged up.

I learnt a valuable lesson that evening, namely to reduce the float
charging voltage from the 2.133v per cell typically set by default with
UPSes down to the less abusive 2.1v value if you want your very expensive
"consumable" to last more than just a lousy two or three years (assuming
few to no brief mains outages in that time and that the automated weekly
battery test feature is also disabled).


I've regarded 13.0V on a 12V lead acid to be a maintenance charge.

Keeping a battery at a float charge level is said to enhance plate
corrosion over leaving it to stand and charge periodically.
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On 23/04/2021 11:25, Dave Plowman (News) wrote:
In article ,
alan_m wrote:
On 22/04/2021 14:27, Dave Plowman (News) wrote:


It's why they no longer fit oil pressure gauges, ammeters and accurate
temperature gauges to cars these days. All they did was cause worry to
most.


But these parameters are being monitored and if you connect a OBDII
device to the diagnostic port you can see such items on a smart phone or
tablet.


One would hope that if you go to those lengths, you'd know what the
readings mean. Unlike the average motorist. But such gauges disappearing
started long before code readers.


The point is that the engine management system/computer is still
monitoring these functions and the computer programming has more inbuilt
knowledge about the parameters being monitored than the average driver
ever had.

My car now even has a message coming up on the dash if the fluid in the
windscreen washer bottle is getting low and I'm guess I would get a
similar message if the oil pressure was low or the engine was running
over temperature.

--
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On 24/04/2021 11:48, Dave Plowman (News) wrote:


Immobiliser? Radio memory? I'm sure the makers of expensive cars would do
everything they could to reduce quiescent load.


I really don't see an answer to it with modern cars. And I'm sure many
very clever engineers have given it much thought.


All data could be stored in non-volatile memory requiring no power to
maintain it when the cars ignition is turned off, or key/fob removed.

I guess the biggest user of standby power on a car is remote locking and
the alarm.



--
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On 21/04/2021 13:22, Jeff Layman wrote:
My car has automatic engine stop when the footbrake is on and the car is
stationary. My understanding is that the battery is specifically
designed to cope with repeated starts. There were a number of conditions
where that would not apply (such as A/C running), but also where the
battery capacity and/or voltage was not deemed sufficient (by software?)
to restart the engine when the brake was released.


You mean the manufacturer has designed in a feature designed to make you
annoy the people behind you?

https://www.highwaycodeuk.co.uk/ligh...uirements.html

"In stationary queues of traffic, drivers should apply the parking brake
and, once the following traffic has stopped, take their foot off the
footbrake to deactivate the vehicle brake lights. This will minimise
glare to road users behind until the traffic moves again."

Andy
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On Sun, 25 Apr 2021 17:10:12 +0100, Fredxx wrote:

On 25/04/2021 05:47, Johnny B Good wrote:
On Fri, 23 Apr 2021 19:00:40 +0100, Fredxx wrote:

=====snip=====


I learnt a valuable lesson that evening, namely to reduce the float
charging voltage from the 2.133v per cell typically set by default with
UPSes down to the less abusive 2.1v value if you want your very
expensive "consumable" to last more than just a lousy two or three
years (assuming few to no brief mains outages in that time and that the
automated weekly battery test feature is also disabled).


I've regarded 13.0V on a 12V lead acid to be a maintenance charge.

Keeping a battery at a float charge level is said to enhance plate
corrosion over leaving it to stand and charge periodically.


It's a balancing act between the risk of sulphation at too low a voltage
and premature corrosion at a high float charging voltage. 13.8v per six
cell SLA (Gel or AGM) when sustained year in, year out, in a UPS
application is IMO, way too high.

A more sensible choice of float charge voltage in this usage case would
appear to be that 13.5v value often noted as the optimum operating
voltage for mobile transceivers.

When I recommissioned my APC SmartUPS2000 with a cheap set of four 7AH
alarm batteries almost three years ago to prove its compatibility with a
cheap Lidl 1/1.2KW Parkside 'suitcase' inverter genset, I adjusted the
float voltage down from the 55.2 originally set by APC to 54v (actually,
the float charging circuit has a very soft voltage regulation and had
crept up to 55.5v over the years since I'd last tweaked the relevant
trimpot to set it bang on the 55.2v mark per the 13.8v standard, ignorant
of this high voltage setting being the cause of early battery failure at
that time).

Incidentally, APC specify an 18AH 48v battery pack for this UPS model
which would cost somewhere in the region of 200 quid for an equivalent to
the APC supplied battery pack which, afair, was priced in the region of
320 quid! Those 7AH alarm batteries will be hard pushed to give more than
a minute's run time at the full 1500W loading so I'm giving serious
consideration to investing in an 80 to 100AH 16 cell LFP battery pack to
eliminate the overpriced short lived inefficient 'consumable' from the
equation.

The larger capacity UPSes tend to be designed to safely utilise an
additional battery bank or three without overheating (they incorporate a
cooling fan or two). That SmartUPS2000 of mine has one such
thermostatically controlled fan but the ventilation owes too much of its
design to aesthetics and not enough to function. I'll be cutting out the
'vent slots' (fan and intake) and fitting a wire finger guard on the
intake - the fan doesn't really need one since it will give a warning
sting to anyone foolish enough to try and shove their fingers into where
they don't belong.

Anyhow, my point is that just last week, I decided to risk pressing the
'Test' button to see if there'd be any sign of deterioration of the
battery pack's condition after three years of service. I'm happy to say
only the top led in the column of five extinguished as per the initial
commissioning tests so it looks like my decision to dial the float
charging voltage 'back a notch' has actually paid off.

A lot of owner / users of APC UPS kit have for many years, noted and
complained about the rather short service life of the batteries
(typically just two to three years before they're totally shagged) but APC
are not alone in defaulting to this common 13.8v per six cell SLA setting
- it's an "Industry Standard" that maximises the initial autonomy for a
laughably marginal battery pack AH sizing.

I haven't seen any actual figures on this but I suspect reducing the
float voltage down to 13.5v simply reduces the effective from brand new
initial capacity by some 5 to 10 percent in exchange for a doubling,
possibly even a tripling, of battery service life. Considering just how
expensive these 'consumables' are to replenish, trading a few percent of
autonomy for a considerably extended battery life is a no brainer choice
in my view.

Most recent models of UPS can be adjusted to a lower float charge
voltage setting by the user so it's an option that's worth investigating
if you want to reduce the TCO of your UPS.

My experience over the past 5 or 6 years with that 2nd hand 12AH SLA
suggests that the 13v maintainance figure you quoted will indeed protect
an SLA against sulphation but, of course, the downside is that it won't
be charged to its full capacity.

No great problem when its being stored and not expected to provide
backup power at an instant's notice. It'll just need a boosting charge to
13.8 volts prior to being used or placed into service. If it's one of a
bunch set aside to replenish a knackered UPS battery pack, the UPS will
do this for you whether it's been set for 13.8 or 13.5 volts per 6 cell
float voltage setting.

Just one final observation (to get back on topic, sort of) SLI LA
batteries (car batteries) are totally unsuited as a cheap alternative to
SLAs for UPS service.

I found this out the hard way (I can be a slow learner at times) by
going through TWO sets of NOS 36AH SLI batteries, each only surviving 6
to 8 months tops (and ONLY THEN did I recall a similar experience with a
4A 13.8v CB power supply floating a 48AH SLI battery some thirty years
earlier which I'd simply shrugged off as a faulty battery at that time).
Luckily, each of these sets of four car batteries had only cost me sixty
quid - it could so easily have been a lot more expensive a lesson!


--
Johnny B Good


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On 23/04/2021 01:07, Fredxx wrote:

Couldn't the manufacturers fit a separate small battery dedicated to
supplying the quiescent items? One that would last maybe ten days.
With a user option to decide whether it should steal power from the
main battery when it became depleted?


At 50mA that would be less than the self discharge rate of a lead acid
battery.

I therefore don't see the point, it would also make a car even more
complex than it they are already. And you've have to replace two
batteries rather than the one. For some cars a battery change is already
a dealer operation.


The fact is that people are being inconvenienced all the time by the
quiescent drain preventing the car from starting. It shouldn't be beyond
the wit of man to find a solution.

Bill
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On 23/04/2021 19:00, Fredxx wrote:
On 23/04/2021 13:44, Dave Plowman (News) wrote:
In article ,
*** Fredxx wrote:
At 50mA that would be less than the self discharge rate of a lead acid
battery.


Not so. A lead acid in good condition has a very low self discharge rate.


More than a 1,000 hours?


My tractor wasn't used for five months and it started instantly.

Bill
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On 23/04/2021 19:11, Fredxx wrote:

The last Transit I owned had two lead acid batteries of equal size.
During cranking and running they were connected together. At other times
one was isolated from any gizzmos and so zero drain.


My 2009 Transit has that arrangement. It works well. The two batteries
are squeezed in under the driver's seat.

Bill
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On 24/04/2021 01:06, Fredxx wrote:

So effectively a larger battery. That is one solution, but an expensive
one. And some will still leave it long enough for them to go flat.



In this case only one of these batteries would be flat. As soon as the
ignition switch is turned the two batteries are connected. I dread to
think the magnitude of current flow in the first few seconds.

Any flattened lead acid battery is going to be toast, or severely damaged.


I don't know why but I can tell you that that just doesn't happen. I
don't know why. Maybe when the starter load is present there just isn't
a rush of current between batteries.

Bill
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On 25 Apr 2021 at 18:58:10 BST, "alan_m" wrote:

On 23/04/2021 11:25, Dave Plowman (News) wrote:
In article ,
alan_m wrote:
On 22/04/2021 14:27, Dave Plowman (News) wrote:


It's why they no longer fit oil pressure gauges, ammeters and accurate
temperature gauges to cars these days. All they did was cause worry to
most.


But these parameters are being monitored and if you connect a OBDII
device to the diagnostic port you can see such items on a smart phone or
tablet.


One would hope that if you go to those lengths, you'd know what the
readings mean. Unlike the average motorist. But such gauges disappearing
started long before code readers.


The point is that the engine management system/computer is still
monitoring these functions and the computer programming has more inbuilt
knowledge about the parameters being monitored than the average driver
ever had.

My car now even has a message coming up on the dash if the fluid in the
windscreen washer bottle is getting low and I'm guess I would get a
similar message if the oil pressure was low or the engine was running
over temperature.


If only - the first warning I had of a failing battery was the dash dials
going haywire, and then the car came to a stop.

Rather less baffling is why the brake pad wear indicators hadn't come on after
Halfords, for three consecutive years, reported low pad levels as an advisory
at MOT time.

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Cheers, Rob




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On 26/04/2021 07:50, RJH wrote:

If only - the first warning I had of a failing battery was the dash dials
going haywire, and then the car came to a stop.


Albeit on a 5+ year old battery I once had a failure overnight. The
previous day it started the car which had been sitting for 18 hours in
temperatures below 0C. It started the car a couple of more times during
the day. Previously there had been no indication of a failing battery
and my daily commute was 30+ miles. On the morning of the failure the
dash lights came on for a second or two and then dimmed to nothing, a
turn of the key resulted in zilch. A morning on the charger did nothing.

A new battery restored everything to working order.


Rather less baffling is why the brake pad wear indicators hadn't come on after
Halfords, for three consecutive years, reported low pad levels as an advisory
at MOT time.


I once had disks and pads replaced by a local garage and years later
when replacing the pads myself found that the low pad wires had not been
connected - they had been neatly coiled up and cable tied safely out of
the way.

--
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On Mon, 26 Apr 2021 06:50:17 +0000 (UTC), RJH
wrote:

snip

If only - the first warning I had of a failing battery was the dash dials
going haywire, and then the car came to a stop.


snip

That was similar to when I was driving my mates AMG Merc to a dealers
and it also came up with some form of 'Battery' fault before cutting
out, before I could even turn round to take it back to his (about 2
miles away).

It had a big battery in the boot for running most things and a smaller
one in the engine bay to start the engine.

'Apparently' it was the dual output alternator and put around 750 on
the cost of the car before he could sell it. ;-(

Cheers, T i m

p.s. Got caught in some bad traffic the other day and the old Meriva
started running on 3 cylinders and it threw up an engine management
light (that reminds me, I should code read that and see what it was).

Using it again later (after it had cooled down) it seemed to behave ok
but had also fixed the odometer backlight that had been out for about
6 months. ;-)
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Default OT: Car battery volt drop

alan_m wrote:

I once had disks and pads replaced by a local garage and years later
when replacing the pads myself found that the low pad wires had not been
connected - they had been neatly coiled up and cable tied safely out of
the way.


I had a pad on my Renault 20 wear down to the backing, which made
for a gentle run home. There was a monitoring wire which fed an
indicator, but because it was connected only to the pad on the
easiest side to run the wire, it was also on the side of the
caliper which wore least.

:-(

Chris
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Default OT: Car battery volt drop



"williamwright" wrote in message
...
On 23/04/2021 01:07, Fredxx wrote:

Couldn't the manufacturers fit a separate small battery dedicated to
supplying the quiescent items? One that would last maybe ten days. With
a user option to decide whether it should steal power from the main
battery when it became depleted?


At 50mA that would be less than the self discharge rate of a lead acid
battery.

I therefore don't see the point, it would also make a car even more
complex than it they are already. And you've have to replace two
batteries rather than the one. For some cars a battery change is already
a dealer operation.


The fact is that people are being inconvenienced all the time by the
quiescent drain preventing the car from starting. It shouldn't be beyond
the wit of man to find a solution.


There is no solution. You either turn off what does the quiescent drain and
lose the alarm protection or you live with the fact that the car wont start.

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Default OT: Car battery volt drop



"williamwright" wrote in message
...
On 23/04/2021 19:00, Fredxx wrote:
On 23/04/2021 13:44, Dave Plowman (News) wrote:
In article ,
Fredxx wrote:
At 50mA that would be less than the self discharge rate of a lead acid
battery.

Not so. A lead acid in good condition has a very low self discharge
rate.


More than a 1,000 hours?


My tractor wasn't used for five months and it started instantly.


Unlikely to have a proper alarm.



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Default More Heavy Trolling by the Senile Octogenarian Nym-Shifting Ozzie Cretin!

On Mon, 26 Apr 2021 19:33:11 +1000, Fred, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:

FLUSH the trolling senile asshole's latest troll**** unread


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Default Lonely Obnoxious Cantankerous Auto-contradicting Senile Ozzie Troll Alert!

On Mon, 26 Apr 2021 19:30:50 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

FLUSH the trolling senile asshole's latest troll**** unread


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Default OT: Car battery volt drop

In article ,
alan_m wrote:
The point is that the engine management system/computer is still
monitoring these functions and the computer programming has more inbuilt
knowledge about the parameters being monitored than the average driver
ever had.


My car now even has a message coming up on the dash if the fluid in the
windscreen washer bottle is getting low and I'm guess I would get a
similar message if the oil pressure was low or the engine was running
over temperature.


I'm not really sure we need a sophisticated computer to tell you the
windscreen washers are running low on fluid? After all many cars have told
you about the fuel running low for quite a few years. ;-)

--
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Dave Plowman London SW
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Default OT: Car battery volt drop

In article ,
williamwright wrote:
On 23/04/2021 01:07, Fredxx wrote:


Couldn't the manufacturers fit a separate small battery dedicated to
supplying the quiescent items? One that would last maybe ten days.
With a user option to decide whether it should steal power from the
main battery when it became depleted?


At 50mA that would be less than the self discharge rate of a lead acid
battery.

I therefore don't see the point, it would also make a car even more
complex than it they are already. And you've have to replace two
batteries rather than the one. For some cars a battery change is already
a dealer operation.


The fact is that people are being inconvenienced all the time by the
quiescent drain preventing the car from starting. It shouldn't be beyond
the wit of man to find a solution.


The answer is very simple. Either use the car before the battery goes
flat, or charge the battery.

Cars run out of petrol too. No clever electronics can stop that - it
involves some sense on the part of the driver.

--
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Dave Plowman London SW
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Default OT: Car battery volt drop

In article ,
alan_m wrote:
I once had disks and pads replaced by a local garage and years later
when replacing the pads myself found that the low pad wires had not been
connected - they had been neatly coiled up and cable tied safely out of
the way.


Most brake pad warning systems show an error if the sensors aren't
connected.

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


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Default OT: Car battery volt drop

In article ,
RJH wrote:
Rather less baffling is why the brake pad wear indicators hadn't come on
after Halfords, for three consecutive years, reported low pad levels as
an advisory at MOT time.


I had that too. Pads and discs. Have new ones standing by to be fitted.
When the warning comes on.

Of course the tester is guessing on how hard or not you are on brakes. How
the car is driven/used make a big difference to pad life.

--
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Dave Plowman London SW
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Default OT: Car battery volt drop

On Mon, 26 Apr 2021 04:40:07 +0000, Johnny B Good wrote:

Anyhow, my point is that just last week, I decided to risk pressing the
'Test' button to see if there'd be any sign of deterioration of the
battery pack's condition after three years of service. I'm happy to say
only the top led in the column of five extinguished as per the initial
commissioning tests so it looks like my decision to dial the float
charging voltage 'back a notch' has actually paid off.


I do an automatic (triggered by the controlling PC) test once a week. I
run the test, then report what the capacity is after a fixed period of
time. If it's not 100%, I know the battery is starting on its way out.

I replaced one a couple of weeks ago. The short test dropped it to 75%
immediately, and it didn't recover quickly at all.



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wish to copy them they can pay me £1 a message.
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Default OT: Car battery volt drop

On 26/04/2021 11:09, Dave Plowman (News) wrote:
In article ,
williamwright wrote:
On 23/04/2021 01:07, Fredxx wrote:


Couldn't the manufacturers fit a separate small battery dedicated to
supplying the quiescent items? One that would last maybe ten days.
With a user option to decide whether it should steal power from the
main battery when it became depleted?

At 50mA that would be less than the self discharge rate of a lead acid
battery.

I therefore don't see the point, it would also make a car even more
complex than it they are already. And you've have to replace two
batteries rather than the one. For some cars a battery change is already
a dealer operation.


The fact is that people are being inconvenienced all the time by the
quiescent drain preventing the car from starting. It shouldn't be beyond
the wit of man to find a solution.


The answer is very simple. Either use the car before the battery goes
flat, or charge the battery.

Cars run out of petrol too. No clever electronics can stop that - it
involves some sense on the part of the driver.


There is a fuel gauge for fuel, there isn't an equivalent for the
battery when left unattended.


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Default OT: Car battery volt drop

On 26/04/2021 07:10, williamwright wrote:
On 24/04/2021 01:06, Fredxx wrote:

So effectively a larger battery. That is one solution, but an expensive
one. And some will still leave it long enough for them to go flat.



In this case only one of these batteries would be flat. As soon as the
ignition switch is turned the two batteries are connected. I dread to
think the magnitude of current flow in the first few seconds.

Any flattened lead acid battery is going to be toast, or severely
damaged.


I don't know why but I can tell you that that just doesn't happen. I
don't know why. Maybe when the starter load is present there just isn't
a rush of current between batteries.


If the relay can reliably cope with the starter current in the coldest
latitude then I suspect with the odd occasion when one battery is flat,
creating an inrush, the relay's going to survive the event.
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Default OT: Car battery volt drop

On 26/04/2021 07:08, williamwright wrote:
On 23/04/2021 19:11, Fredxx wrote:

The last Transit I owned had two lead acid batteries of equal size.
During cranking and running they were connected together. At other
times one was isolated from any gizzmos and so zero drain.


My 2009 Transit has that arrangement. It works well. The two batteries
are squeezed in under the driver's seat.


Squeezed is an understatement! LOL


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Default OT: Car battery volt drop

On 22/04/2021 14:37, Dave Plowman (News) wrote:
In article , Roger Hayter
wrote:
On 22 Apr 2021 at 12:18:49 BST, "Adrian Brentnall"
wrote:


On 22/04/2021 11:14, Dave Plowman (News) wrote:
In article , Brian Gaff \(Sofa\)
wrote:
What somebody electronically minded did on a battery where you can
actually get at the cell interconnects, few these days, sadly, he
put a monitor so it looked at every cell on its own and then he
could tell the weak cell or cells, but as to what to do with such
info, who knows? I'm surprised modern car electronics do not
already allow this like they tend to do on Lithium cells these days.

Given there's nothing you can do about a faulty cell in a car
battery, not much point?


As we used to say in industrial automation

"Never check for an error condition you can't handle"

Good advice.


The main one is never create a system where a fault one sensor can break
a correctly functioning piece of equipment. 737 Max failed that way.

It is a sound reason to replace a battery if you are not sure whether to
do so.


Given the cost, makes sense to have it tested first? There are
sophisticated testers that give an instant readout of the condition. A bit
too expensive for DIY, but a decent spares place should have one. ACT is
one such.

However, if you charge the battery with one of those £14 Lidl chargers,
and it struggles to start the car, there's a very good chance it is faulty.


The acid test is will it start the car the following day after being
taken off charge. A newly recharged car battery has to be incredibly bad
not to be able to start the car at least once. Mine had been on its last
legs for a while but the lockdown this winter finished it off.

--
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Default OT: Car battery volt drop

In message , Chris J Dixon
writes
alan_m wrote:

I once had disks and pads replaced by a local garage and years later
when replacing the pads myself found that the low pad wires had not been
connected - they had been neatly coiled up and cable tied safely out of
the way.


I had a pad on my Renault 20 wear down to the backing, which made
for a gentle run home. There was a monitoring wire which fed an
indicator, but because it was connected only to the pad on the
easiest side to run the wire, it was also on the side of the
caliper which wore least.

:-(

The instructions for my Mk2 Cortina said (something like) that the brake
pads should be replaced when the thickness was between an 1/8th and
3/32nds of an inch. I always wondered what you should do if the
thickness had worn down to less than 3/32nds of an inch!
--
Ian
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Default OT: Car battery volt drop

In article ,
Fredxx wrote:
On 26/04/2021 11:09, Dave Plowman (News) wrote:
In article ,
williamwright wrote:
On 23/04/2021 01:07, Fredxx wrote:


Couldn't the manufacturers fit a separate small battery dedicated to
supplying the quiescent items? One that would last maybe ten days.
With a user option to decide whether it should steal power from the
main battery when it became depleted?

At 50mA that would be less than the self discharge rate of a lead acid
battery.

I therefore don't see the point, it would also make a car even more
complex than it they are already. And you've have to replace two
batteries rather than the one. For some cars a battery change is already
a dealer operation.


The fact is that people are being inconvenienced all the time by the
quiescent drain preventing the car from starting. It shouldn't be beyond
the wit of man to find a solution.


The answer is very simple. Either use the car before the battery goes
flat, or charge the battery.

Cars run out of petrol too. No clever electronics can stop that - it
involves some sense on the part of the driver.


There is a fuel gauge for fuel, there isn't an equivalent for the
battery when left unattended.


You don't need a gauge. Just a calender. Pretty well everyone knows a
battery goes flat in not that long when left connected in the car.

Mate with a motorhome which is obviously not used as often as a car can
see the battery state via his phone. IIRC, it also sends him a warning
when getting low.

--
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Dave Plowman London SW
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Default OT: Car battery volt drop

On Mon, 26 Apr 2021 14:03:25 +0100, "Dave Plowman (News)"
wrote:

snip

You don't need a gauge. Just a calender.


Or solar panel. ;-)

Pretty well everyone knows a
battery goes flat in not that long when left connected in the car.


Depending on the car. We didn't use the Meriva for a good few months
and it started fine. The 407 that daughter bought cheap wouldn't
restart after being left for 5 days. We fitted a new battery on it and
it's been fine ever since (and this is in the lockdown). I tested the
old one and it was ok for one test cycle then failed on the second
(one cell short I think).

Mate with a motorhome which is obviously not used as often as a car can
see the battery state via his phone.


I did have such (badged Accutire) on a motorbike but it's off (beside
me) atm.

https://www.amazon.co.uk/Accutire-MS.../dp/B00X1MMNIG

IIRC, it also sends him a warning
when getting low.


I think I disconnected it before mine did (I'll have to stick another
CR2032 in it, hook it up again and check it out).. ;-)

Cheers, T i m



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Default OT: Car battery volt drop

On 26/04/2021 10:33, Fred wrote:


"williamwright" wrote in message
...
On 23/04/2021 19:00, Fredxx wrote:
On 23/04/2021 13:44, Dave Plowman (News) wrote:
In article ,
*** Fredxx wrote:
At 50mA that would be less than the self discharge rate of a lead acid
battery.

Not so. A lead acid in good condition has a very low self discharge
rate.

More than a 1,000 hours?


My tractor wasn't used for five months and it started instantly.


Unlikely to have a proper alarm.


TBH, my suggestion/question of hours was for a self-discharge time when
not attached to a vehicle and therefore Bill's experience is pretty
close to that.

I based 1,000 hours on a 50mA discharge for a 50Ah battery, and we have
established the self discharge rate for a typical 50Ah battery would be
~2mA.


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Default OT: Car battery volt drop

On 26/04/2021 08:54, alan_m wrote:
On 26/04/2021 07:50, RJH wrote:

If only - the first warning I had of a failing battery was the dash dials
going haywire, and then the car came to a stop.


Albeit on a 5+ year old battery I once had a failure overnight. The
previous day it started the car which had been sitting for 18 hours in
temperatures below 0C.* It started the car a couple of more times during
the day. Previously there had been no indication of a failing battery
and my daily commute was 30+ miles. On the morning of the failure the
dash lights came on for a second or two and then dimmed to nothing, a
turn of the key resulted in zilch. A morning on the charger did nothing.

A new battery restored everything to working order.



What sort of battery did you have. I now have a car with an AGM battery
for stop start. I am now wondering how long it will last and what a
failure will be like. For the past 25 years my cars have normally
started very easily so I don't notice that the battery is failing. One
car would not start so I charged the battery, drove about 10 miles to
buy a new one and then the car would not start to come home until I
fitted the new battery. Fortunately I had the tools I needed with me.


--
Michael Chare
battery is starting to fail.
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Default OT: Car battery volt drop

On 25/04/2021 19:09, alan_m wrote:
On 24/04/2021 11:48, Dave Plowman (News) wrote:


Immobiliser? Radio memory? I'm sure the makers of expensive cars would do
everything they could to reduce quiescent load.


I really don't see an answer to it with modern cars. And I'm sure many
very clever engineers have given it much thought.


All data could be stored in non-volatile memory requiring no power to
maintain it when the cars ignition is turned off, or key/fob removed.

I guess the biggest user of standby power on a car is remote locking and
the alarm.



Depends if you are a dick like me:-)

I left the dashcam in the car plugged in for three weeks and flattened
the battery [1].

The car's "cig lighter" socket is always on unlike the works van.

[1] Just enough so that it did not have enough juice to start the car.
Diesel on a cold morning etc.


--
Adam
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Default OT: Car battery volt drop

On 26 Apr 2021 at 11:11:29 BST, ""Dave Plowman" News)"
wrote:

In article ,
alan_m wrote:
I once had disks and pads replaced by a local garage and years later
when replacing the pads myself found that the low pad wires had not been
connected - they had been neatly coiled up and cable tied safely out of
the way.


Most brake pad warning systems show an error if the sensors aren't
connected.


That may be true of more sophisticated cars but the two Fords I had about 10
and fifteen years ago simply had a single wire that was open circuit until the
pad contact wore down to short it to earth. So they had no idea whether they
were connected.

--
Roger Hayter


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Default OT: Car battery volt drop

On 26/04/2021 11:11, Dave Plowman (News) wrote:
In article ,
alan_m wrote:
I once had disks and pads replaced by a local garage and years later
when replacing the pads myself found that the low pad wires had not been
connected - they had been neatly coiled up and cable tied safely out of
the way.


Most brake pad warning systems show an error if the sensors aren't
connected.


They may do now but the operation of these seemed to be open circuit
when the pads were new and a short circuit to the disk when worn.

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Default OT: Car battery volt drop

On 26/04/2021 19:06, Michael Chare wrote:
On 26/04/2021 08:54, alan_m wrote:
On 26/04/2021 07:50, RJH wrote:

If only - the first warning I had of a failing battery was the dash
dials
going haywire, and then the car came to a stop.


Albeit on a 5+ year old battery I once had a failure overnight. The
previous day it started the car which had been sitting for 18 hours in
temperatures below 0C.* It started the car a couple of more times
during the day. Previously there had been no indication of a failing
battery and my daily commute was 30+ miles. On the morning of the
failure the dash lights came on for a second or two and then dimmed to
nothing, a turn of the key resulted in zilch. A morning on the charger
did nothing.

A new battery restored everything to working order.



What sort of battery did you have. I now have a car with an AGM battery
for stop start.* I am now wondering how long it will last and what a
failure will be like.* For the past 25 years my cars have normally
started very easily so I don't notice that the battery is failing. One
car would not start so I charged the battery, drove about 10 miles to
buy a new one and then the car would not start to come home until I
fitted the new battery. Fortunately I had the tools I needed with me.




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