Battery keeps going flat

[daznkel]

Originally Posted by Dallas

I only have a 0.47ma reading, which means there is no drain on the battery to cause it to go flat.

A 0.47mA current flow from a standing locked car IMHO is absolutely fine. More than likely, just enough to keep the alarm etc active.

Does seem unlikely that every battery is kaput though. But as already pointed out, the only way to truly test whether a battery is good or not is a Load pull test, which most independent car battery sellers will do FOC.

[SD1too]

Originally Posted by Dallas

Q: Also how do you know all these batteries you mention are all fully charged ???
A: The 3 spare batteries I keep charged, only select the long slow trickle charge option ...

How do you achieve this Dallas? Are all three connected to the trickle charger at the same time,in parallel?

Simon

[MSS]

Originally Posted by Dallas

It was nice talking with you Steve, appreciated the advice.

I've just been outside in the cold and performed the Parasitic test draw, and BINGO! I only have a 0.47ma reading, which means there is no drain on the battery to cause it to go flat.

It looks like all 3 spare batteries I have are rubbish, which is hard to believe considering one is only 10 months old, and was perfectly fine on the car it came from.

I have no battery/alternator light on dash, have no reason to believe the battery isn't charging. The car doesn't get driven much, but my red ZT doesn't either, car can stand for 2 weeks with no use and battery has been perfectly fine for two years.

I guest I have 4 deteriorating batteries that will not hold a charge, maybe its time for a new battery.

Thanks again for all the help guys, very much appreciated.

Your idle state current consumption reading (current with the doors/bonnet shut and car locked) does't seem right. Are you sure it is not 0.47A, i.e. 470mA?

A current consumption of 0.47mA is not sufficient to power the car's circuitry in the idle state. A long-idle state current of 20 to 50mA would be more typical for a "modern car" depending on the power-down state of the electronics.

If it is 470mA, I would start off by checking the 5W light bulbs e.g. glove compartment light.

If you are unable to find something obvious, the best way forward is to check the current drain whilst systematically removing fuses.

[T-Cut]

MG Rover Technical Tip TT0036
Maximum expected battery current drain
Ignition off for up to 18 minutes: 1 to 2 amps
Ignition off after 18 minutes (sleep mode): 30 to 45 mA


TC

[MSS]

Originally Posted by T-Cut

MG Rover Technical Tip TT0036
Maximum expected battery current drain
Ignition off for up to 18 minutes: 1 to 2 amps
Ignition off after 18 minutes (sleep mode): 30 to 45 mA


TC

Thanks for the confirmation TC.

So, as above, 0.47mA is not correct and suggests a problem with the measurement. The expected measurement would be over 20mA and under 50mA in idle (sleep) mode.

[Blackrose]

I think Wes's experience with the voltmeter might not be as good as some on here. I'll bet it's 47mA and all is well.
Or it could be .47 of one amp on a 0-10a scale. Almost half an amp which could be a small bulb as suggested.
The small cheap digital meters usually just have a 0-10a scale.

Blackrose

[Dallas]

Originally Posted by SD1too

How do you achieve this Dallas? Are all three connected to the trickle charger at the same time,in parallel?

Simon

Hi Simon, Sorry, I may have not explained the situation fully. .
The spare batteries are not on any vehicle, they are kept in my little workshop. Each one gets charged separately using a regular 12V battery charger that is set to 'trickle' charge (not the fast-charge option), usually left on charge for 24 hours.

Originally Posted by mss

Your idle state current consumption reading (current with the doors/bonnet shut and car locked) does't seem right. Are you sure it is not 0.47A, i.e. 470mA?

A current consupmtion of 0.47mA is not sufficient to power the car's circuitry in the idle state. A long-idle state current of 20 to 50mA would be more typical for a "modern car" depending on the power-down state of the electronics.

If it is 470mA, I would start off by checking the 5W light bulbs e.g. glove compartment light.

If you are unable to find something obvious, the best way forward is to check the drain whilst systematically removing fuses.

Originally Posted by T-Cut

MG Rover Technical Tip TT0036
Maximum expected battery current drain
Ignition off for up to 18 minutes: 1 to 2 amps
Ignition off after 18 minutes (sleep mode): 30 to 45 mA

TC

Originally Posted by Blackrose

I think Wes's experience with the voltmeter might not be as good as some on here. I'll bet it's 47mA and all is well.
Or it could be .47 of one amp on a 0-10a scale. Almost half an amp which could be a small bulb as suggested.
The small cheap digital meters usually just have a 0-10a scale.

Blackrose

Thanks fellas, now you have me really confused.

Something does seem quite strange, or unless its my readings or settings, or my cheap meter.
I have just been and checked again, ignition off and car was not started, so vehicle should be in (sleep mode). The reading I got this time was 0.29ma, if I open the drivers door to trigger the interior lights, I get a 1.91ma reading, I'm not sure why I had a 0.47 reading last night.

The battery reading with noting attached reads 12.64v, and battery reading with engine running is 14.44v, this would indicate my alternator is charging the battery which is nice to know.

Does this all sound correct to you guys, or am I doing something wrong?

Cheers all.

Ignition off, doors closed, car was not started.


Reading with door open.


Battery reading with nothing connected: 12.64v.


Battery reading with engine running: 14.44v, would indicate the alternator is charging the battery.

[Blackrose]

I think it's OK. Anyone disagree

Blackrose

[COLVERT]

It looks like you are on a ten amp scale.

.29 is over quarter of an amp.

This would take quite a while to discharge your battery but it would slowly do that.

That TRICKLE charge you talk about OVERNIGHT. NO !!!!!

That trickle charge should be permanently on as a maintenance charge.
( Usually around one amp or a little less. )

You could put three fully charged batteries on in parallel with that sort of charge and it would just about cope with them.

( Have you had a read about batteries in the section at the top of the main page entitled-----

REALLY, REALLY useful section ??? )

[COLVERT]

Your battery reading is correct.


Your charging reading is correct.



Your meter is working just fine.



However you STILL have a LARGE current leak somewhere.---- ( well, large-ish for a leak. Lol )


There's a small bulb, hidden away, just gently glowing somewhere.--Keeping the mice in your wiring warm.--