What is killing my New Battery?

falling-out-with-my-car · Post by **falling-out-with-my-car** » 31 Dec 2009, 11:58

Hi,

my xantia estate has been parked up now for about two weeks.

what could be drawing so much power that a reletively new battery goes flat within two weeks?

could this be the alarm or maybe the computer?
or is it just the really low temperatures we have had recently?

I charged the heavy duty battery when I bought it for three days.

thanks in advance

regards Nigel.

Post by **KennyW** » 31 Dec 2009, 12:05

Nigel,

I presume you have done all the checks on the charging circuit for faulty alt etc.

As something is draining your battery e.g faulty alt.

Kenny

falling-out-with-my-car · Post by **falling-out-with-my-car** » 31 Dec 2009, 12:19

In daily use the battery has been 100% reliable and the alternator seems to check out ok.

it must be the alarm /imobiliser or something else.

xantiav6 · Post by **xantiav6** » 31 Dec 2009, 12:42

You can't really guess these things, you need to hook up a suitable amp meter and pull fuses and disconnect things to isolate the current draw.

A seemingly good alternator can have enough reverse leakage to drain a battery.

Maybe a trickle charger or a little solar charger would be an easier solution?

deian · Post by **deian** » 31 Dec 2009, 12:48

one way to check as the car is now (off, but still draining) is to pull out the fuses and relays one by one in the engine compartment and interior, if you see a slight spark (indication of current) between one of them when you put the fuse back in then that would be a good place to start checking the particular circuit

if when you pull the fuses out you don't see sparks as such, then the current may be too low to notice any sparks but still be able to drain enough, in this case, put a voltage meter across the battery with the car off, if when fuly charged it should show something like 12 to 13 volts (only 14.4 with the engine running), whatever the reading is, make a note, now go pulling fuses out one by one and see if the voltage goes up when pulling a certain fuse, if it does then that is the culprit

i would guess relays can become stuck in this weather, making a connection thus draining a battery.

as for the battery, cold weather can really test any battery, if it's the type, check the water, but i would assume all should be ok if it's a new one

thats what i would do myself, hope it helps

falling-out-with-my-car · Post by **falling-out-with-my-car** » 31 Dec 2009, 12:57

ok thanks will have a tinker when it warms up a bit, its freezing at the momenht as anyone would know if they were working on their car.

HDI · Post by **HDI** » 31 Dec 2009, 13:00

Almost impossible to diagnose without doing a check with a meter to see if there is any draw beyond a few 10's of milliamps with the engine off.
I doubt it's the alternator as it's electrically isolated from the battery at standstill unless the regulator is faulty , in which case it wouldn't charge properly.

Post by **Peter.N.** » 31 Dec 2009, 15:24

Get yourself a multimeter that does volts and amps. Connect it across the battery with the engine running and you should have around 14 volts. If this is OK disconnect one battery terminal and connect the meter between the battery lead and terminal post, set to amps, if there is any more than say 100ma flowing you have a problem. Dont under any circumstances try starting the car with the meter connected on 'amps'

Peter

HDI · Post by **HDI** » 31 Dec 2009, 16:02

The meter fuse would just pop

Xaccers · Post by **Xaccers** » 31 Dec 2009, 16:18

HDI wrote:The meter fuse would just pop

If you use the fused amp port, my meters have 10A and unfused ones too.

meexi · Post by **meexi** » 31 Dec 2009, 16:31

this sounds the same problem i had with our old Xantia we could not find a fault anywhere tried meter on battery etc.

the car would start in the morning but at lunchtime the battery was dead flat we could not take the car anywhere and ended up trading it in for the Xpic

cachaciero · Post by **cachaciero** » 31 Dec 2009, 16:49

falling-out-with-my-car wrote:In daily use the battery has been 100% reliable and the alternator seems to check out ok.

it must be the alarm /imobiliser or something else.

One shagged diode in the alternator could give you quite a high static current drain but still look good when th engine is running, suggest checking for current drain through the alternator feeder.

cachaciero

xantiav6 · Post by **xantiav6** » 31 Dec 2009, 17:09

cachaciero wrote:
One shagged diode in the alternator could give you quite a high static current drain but still look good when th engine is running, suggest checking for current drain through the alternator feeder.

It doesn't even need a shagged diode. The diodes in alternators typically have a very loose leakage spec, and can leave the factory with several mA leakage per diode. I seem to recall that one make of alternator was not considered a warranty fault if the total leakage was less than 50mA

Chlorate · Post by **Chlorate** » 31 Dec 2009, 18:04

Maybe it needs a little wine!

I hate these videos

HDI · Post by **HDI** » 31 Dec 2009, 18:12

It shouldn't really matter about rectifier leakage at standstill as the regulator disconnects the alternator from the battery.