Battery Drain ?

[J4CKO]

I put a new battery on my 944 in Feb, a Bosch one so am fairly certain it isnt the battery, but at the moment I am not usign it and I come to it and it is slow to crank, then on Sunday it just turned over one and then did the solenoid noise, one quick jump start and it was fine, the voltmeter is reading ok so I guess it is chargign so it leads me to beleive somethign is draingin the current, someone on PH told me to check across the batter for drain and then remove fuses which seems like a plan but anyone else experienced this and is their a likely culprit ?

I would expect it to last longer than a week but how much driving do you need to do to keep the battery topped up ?

Anyoen use those solar things or a trickle charger, is it worth disconnecting the battery ?

 

[zcacogp]

When you say 'The voltmeter is reading OK', what is it reading? Put a voltmeter across it while the engine is running and if it is less than about 14v then you have a charging problem.

If you suspect battery drain then you can test for it; best way is to connect an ammeter in line with the battery (so remove one battery connection and connect the ammeter between the removed connection and the now-empty terminal) and see how many amps are being taken when the car is off and the alarm set. If this is more than a few milliamps then repeat the test, but with the ammeter in each fuse position in turn; this will identify the circuit that is draining the current. It's time-consuming but logical and will identify the problem eventually.


Oli.

 

[ukmastiff]

Also , a 14 month old Bosch Silver battery completely failed on me last month so in light of the price im giving them a miss from now on.
They can indeed fail prematurely though i doubt its your problem as it is rare.

Regards

Mas

 

[cuffn]

Hi Mas

That's unusual for a Bosch battery but I guess there are always some that fail early. I am pretty sure Bosch batteries have a 3 or maybe even 5 year warranty on them though so you should be able to get it replaced FOC.

Cheers

 

[ukmastiff]

Indeed and guess who has kept receipts for every oil filter / jubilee clip bulb etc but mislaid his battery one. I bought it online too from a battery specialist website. Now days i buy almost everything from ECP and so have an audit trail , lesson learned


Silly old Mas !

 

[pauljmcnulty]

Mine turned out to be the glovebox light sometimes staying on; the door wasn't fitting properly and didn't always push the switch in enough. Such a simple thing once you know that's the culprit.

 

[944 man]

http://www.ebay.co.uk/itm/Automotive-Current-Tester-STANDARD-Car-Fuse-Boxe-Test-/260597798106?pt=UK_Sound_Vision_Other&hash=item3cacd6d4da

 

[cuffn]

ORIGINAL: ukmastiff

Indeed and guess who has kept receipts for every oil filter / jubilee clip bulb etc but mislaid his battery one. I bought it online too from a battery specialist website. Now days i buy almost everything from ECP and so have an audit trail , lesson learned


Silly old Mas !

Oh damn - that sounds just like me - it's so frustrating isn't it!

 

[944 man]

Keep the battery receipt if an airtight freezer bag, taped to the underside of the battery.

Tip #2: always take a Halfords battery for a free test, before mentioning a warranty claim. This way theyll have to replace it after declaring it as failed.

 

[bmnelsc]

ORIGINAL: J4CKO

...
Anyoen use those solar things or a trickle charger, is it worth disconnecting the battery ?

I use a "trickle charger" but it is actually a battery maintainer - charges up to fully charged state and then supplies a small current intermittently to keep the battery fully charged. I disconnect my battery (ROW S2 my battery is in the front - not the boot ) as there is no room for the charger clamps with the cables connected. These maintainers can be used with the battery connected so long as you have room to make the connections or you can install the permanent connectors that go under the existing battery terminal clamp bolts.

If you go for a battery maintainer - look for one that has a de-sulphating feature (provides a high current blast to dissolve sulphates that have built up before switching to regular charging mode).

If your battery won't last a week then your battery is probably sulphated (from being run down and recharged many times) - even my old one that failed load testing would last about 2 weeks (summer months). A maintainer may recover it for you or at least. If you replace the battery - a maintainer will keep your battery in like-new condition for years to come.

 

[repsol]

a current drain is a nighmare to find probably the most difficult electrical fault to find

 

[kdp]

I recently bought a 1989 944 Lux and was told it had a recent battery and starter fitted. I found that after a few days it would have trouble starting because of a weak battery. I disconnected the terminals and the voltage remained the same over several days, so the battery was OK. I then connected a low wattage bulb in series at the battery and the bulb lit up which suggested a current flowing. I then pulled each fuse in turn and quickly found that the electric window motor fuse was the culprit as it was easy to see the bulb go out in the boot. I assume it it is a relay problem - anyway I've removed the relay and hopefully all will be fine now, but obviously no electric windows for the minute.

 

[zcacogp]

Keith,

What a very logical and simple diagnostic technique. Many thanks for this - I'll remember it for future use.


Oli.

 

[J4CKO]

Ok, checked it over today, the voltmeter registers a needles width under 14v when driving, the ammeter appears to be reading 70ma drain when the car has the ignition off which sounds a lot, it says 0.07 on the screen and seems consisten, hood is down to make it easier but dont think that makes a difference, have pulled every fuse and relay and nothing made any difference.

Any ideas ?

It has an aftermarket Kenwood stereo and a Clifford alarm led, , cant think of anythign else that may cause it

 

[Catamax944]

ORIGINAL: ukmastiff

Also , a 14 month old Bosch Silver battery completely failed on me last month so in light of the price im giving them a miss from now on.
They can indeed fail prematurely though i doubt its your problem as it is rare.

Regards

Mas

I also had bad experience with a couple of new Bosch batteries , both failed on me in less that 12 months .
On the other hand i am very amazed by my current battery that was supposed to be temporary when my last bosch failed, a Fiamm battery that i took from my old punto diesel before scraping it . I have abused it and it just wont die , it's still as good as new , I don't know it's exact age but i know it's more than 5 years .

 

[J4CKO]

Pretty sure the battery and charging is ok, the ammeter was reading, 70/80 Millamps, sometimes the electric window realy "chatters", usually after some activity so wondering if the door switches are ok, other than that are there any other fuses round the car ?

 

[944 man]

Mark, did you look at the link that I posted? Thisll help you narrow it down very quickly.


Simon

 

[J4CKO]

Simon,

Just ordered one !

 

[944 man]

:thumb:

 

[Veerzigzag]

the ammeter appears to be reading 70ma drain when the car has the ignition off which sounds a lot,

At that current (and hence 0.84 watts), a 70AH battery would take 1000 hours to discharge.
Lots of good stuff on this thread - the diagnostic info is excellent.
I also like the Halfords tip - what a good feeling it must be to have them prove that they must give you a free battery - brilliant!