Battery - dead or alive?

N

Nick C

Member
Hi folks and I hope you're all having a good Christmas.

I'm wondering if I've killed my car (Z4 3.0) battery through lack of use. I've only averaged 230 miles per month during the last 17 months of ownership, the car is March 2004 registered and has a total milege c22,000. The build date is November 2003. This car has virtually every option fitted, so the electrical load demand is accordingly high.

I have got used to recharging the battery every six weeks or so over the last few months and this frequency seemed sufficient to guarantee a successful start. With the low temperature I now have to charge every few days. The ambiguity is this - the yellow indicator (replace battery) isn't showing on the battery, but after twenty hours of charging with a five amp charger, I cant get the green (charged) indicator to show - it remains black (requires charging).

Should I invest in a fifteen amp charger or is four years a fair service life for a car battery subjected the the above pattern of use?

I will contact BMW when the Service Department is open again, but can anyone tell me the cost of a replacement genuine BMW battery.

Thanks for any info. :)
 
Does the standard battery have ports to top up the fluid? If so check the plates are submerged and top up with battery fluid from a car shop if required. Get a big charger and take the battery off the car and give it a nice charge :)

I thought 5amp chargers could only do small batteries, I tried using a cheap charger on the battery of my old car which was smaller than the bmw one and that struggled to make the water fizz. I put a relatives monster charger on it and it was fizzing in no time and revived it from dead. Not bad for a standard 7 year old nissan battery which ran a bit dry once or twice hehe :evil: Was still holding charge and cranking over brilliantly when I sold the car!

In all cases I removed the battery from the vehicle before charging so not to damage the car's ECU.
 
Nick C said:
Hi folks and I hope you're all having a good Christmas.

I'm wondering if I've killed my car (Z4 3.0) battery through lack of use. I've only averaged 230 miles per month during the last 17 months of ownership, the car is March 2004 registered and has a total milege c22,000. The build date is November 2003. This car has virtually every option fitted, so the electrical load demand is accordingly high.

I have got used to recharging the battery every six weeks or so over the last few months and this frequency seemed sufficient to guarantee a successful start. With the low temperature I now have to charge every few days. The ambiguity is this - the yellow indicator (replace battery) isn't showing on the battery, but after twenty hours of charging with a five amp charger, I cant get the green (charged) indicator to show - it remains black (requires charging).

Should I invest in a fifteen amp charger or is four years a fair service life for a car battery subjected the the above pattern of use?

I will contact BMW when the Service Department is open again, but can anyone tell me the cost of a replacement genuine BMW battery.

Thanks for any info. :)
Click to expand...

http://batterytender.com/

Of note: 5 amps of charge should easily get a BMW battery up to full song in a handfull of hours (2-6 depending on discharge) - you may have overcharged your battery on a number of occassions therefore reducing its life.

In Canada a genuine BMW battery runs $200 - $225 CDN.
 
Hmm reading that I thought that you got fair use out of the original battery - were you charging it so often because it needed it, or just to make sure it was ready for you when you wanted to use it?
 
I killed my battery on my previous 3.0 within 2 years by lack of use. I now have a CTEX battery maintainer on it (45 gbp) and it cycles the battery nicely now
 
Nick

The short answer is the battery has probably had it through a combinaion of age and poor use. By that I mean it discharing and recharging and I suspect the wrong type of charger which then overcharges. Batteries can only complete a limited number of cycles and after each one deteriorate slightly, holding ever less charge. They last best when kept constantly charged up, which comes with regular use through driving or of a specific charger matched to the type of battery, correct charge pattern/voltage and switches to maintenance when fully charged. PVR mentions one example.

IMHO there is no need for big chargers - they damage batteries with heat, buckle plates and dry out the cells, especially on sealed and gell where losses cannot be replaced. You also don't need to remove from the vehicle.
 
cj10jeeper, pvr, with you guys using yours as second cars, how long does the battery usually last before it won't start the car then? I take mine on holiday so I never leave it for more than a couple of days without driving it.
 
I've left mine for a couple weeks at a time quite often and never had any troubles. Of course I don't have the Sat/Nav that puts a nice constant drain on the battery when the car is parked.
 
Wondermike said:
cj10jeeper, pvr, with you guys using yours as second cars, how long does the battery usually last before it won't start the car then? I take mine on holiday so I never leave it for more than a couple of days without driving it.
Click to expand...

Mine's not really a second car in the sense of getting left standing. It actually gets used most days. That said I left it while on holiday for over 2 weeks and no problem starting. (I have Sat Nav too)

My 2 Jeeps are normally left for weeks on end and although they do have massive capacity batteries they fire up after weeks if not months.
 
I happened to be in the Bimmer dealership this morning so curiosity about the battery price caused me to ask.

Believe it or not they have had a price increase from £65 to £112 in the last few weeks. The parts guy thought somewhat cynically that this increase was Winter related and they'd be back down again soon...
 
My previous Z would stand for 6 weeks and it would still start fine after that.

The satnav does not drain additionally as the car goes in shutdown mode. The DVD only spins up when you open the doors.

The CTEK 3600 is a very nice piece of kit. I got mine from here
 
pvr, quite a nice site, that :thumbsup:

Hmm £112 for a battery at this time of year too, I agree - a bit cynical indeed.
 
Mine will go into shut down mode of some kind (no clock, trip odometer zero's etc.) after about two weeks, but will still start. Using a battery tender this year - evidently driving the car around the block a few times every two weeks was not enough.
 
I don't use my car 4 months of the year living in Quebec, I keep my batterie on a 1 amp trickle charge in the garage, keeps the batterie just perfect, I would not let a batterie go for more than 1 month without a charge. Also before storage the car is waxed, oil change, and put 'Stabil' in the gas tank and run for a few miles with the fresh oil to get it well lubed and to get the stabil in the entire fuel line. I jack the car up on blocks but not completly the wheels are touching the ground on rubber mats, also cover the car with a clean cotton cover and clean all seals with silicone and protect the leather with a protector, I do that weekly anyway and put steel wool in the muffler.
Can't wait for April 1st.


Dustin
 
Thanks for the additional advice. The battery problem only came about a few weeks ago, prior to that the car could be left for a month and start no problem.
The battery problem occured simultaneously with an alarm fault, possibly due to a rapid voltage drop when the engine was shut down.
I'll see if the battery cost reduces back to £65 within the next few weeks and start using my battery conditioner.

I think for anyone driving infrequently the navigation system is one of the most demanding devices battery wise. It may be best to leave the screen stowed for short journeys in future.
 
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