Flat Battery in 4 weeks

S

srhutch

Legend
 East Sussex, UK
Probably fairly normal, but had to move the car yesterday to get to my bike and it wouldnt start, unlocked fine but no sign of turning over.

In the last 4 1/2 weeks it did one trip to work around 3 weeks ago to work which is about 50 miles round trip. I would have tried to start a week or so ago, but physically there was no way I would have been able to. (just had op on my knee so cant drive can only just walk sort or normally)

Anyway called out BMW assist who first quoted 90 minutes, but within 5 minutes had a text saying 40 minutes, which turned out to be spot on.

Ten seconds after turning up car was started, thats one benefit of having the battery in the boot, as the car was in the garage and would have had to be pushed out.

Went for a 40 minute blast with everything turned off to charge (wasnt much fun with a clutch leg that wont bend)

I guess this period of time is long enough to flatten a battery with all the gadget and gizmos, would you agree?

Have I damaged the battery by letting it go flat alothugh there was a little juice left in as it unlocked etc, but all computer functions were reset.
 
TBH - I dont think your battery should have gone dead in 3 weeks with no use.
I left my old zed for 2 weeks in an airport car park with no starting issues
My prev e46 was left for almost 4 weeks in another airport car park and again no issues

warranty time?
 
Warranty runs out end of December, but as from next week it will be used at least every other day hopefully
 
I had to replace my battery, one cell was dead per dealer, i was gone for 2 weeks, it was true after 7 years i was on borrowed time, have your battery tested!

Bob
 
On my previous Z, I got it replaced under warranty. Leaving it without a charger is not great, so I now have mine on the CTEK always when I am not driving it.
 
My battery lasted for five years. Away from home in Hawaii for four weeks, came back and time for a new one. But for many of our cars that are not daily drivers and are not driven for more than short distances, the batteries have a hard life to live. Getting five years from an OEM battery is pretty good performance in my opinion.
 
my dads z3 battery did this and it was the seat motor on the passenger seat motor that was causing the prob
 
It's impossible to guarantee how long a battery will last left unused. It depends on age, capacity, tyre, alarma and any other minor draws, temperature when you try to use it, etc. etc. It's not by chance that airport car parks start hundreds a week.

Unless it's a special type of battery running it flat or near flat does cause damage. Not terminal but each time it takes a bit out of the battery.

If it does it again or you know the battery is old, swap in a new one.

Pesonally I'd do as pvr and leave it on a maintenance charger if left for long periods.
 
Soon Find out, went to take for spin this morning after not using for a week, and again wont start.

I'm guessing the battery, could put on charge but I am going to get BMW assist out so that I have two sets of paperwork to go to the dealer with.

Time to invest in a Battery Tender I think for those times I dont use the car every other day.
 
Put a meter on it - and I'll guarantee it's only giving something like 11v indicating a dead cell and a new battery required.

No battery tender will have any effect at this stage of life.

New battery then look after it if not used regularly.
 
CJ, I meant get a new battery and keep that one topped up, will go and test with meter now though.
 
Meter is showing 15V

Can I tell what current is being pulled with my meter, if so what setting should it be on?
 
I assume 15v is with the engine running.

I meant off and after it's stood for a little while to settle after any charging up. Mine reads 12.4v on the front engine bay terminals. Less that 12v and oyu have battery issues.

No you can't tell current draw with your meter unless it has the capability to detect amps flow. You can stick one in line between the battery and the lead but just to see if ther is any draw while it's asleep.
 
Car booked into dealer for next Wednesday, BMW assist out tonight to start again. The guy that came out seems to believe something is draining the battery as it is lasting more than a couple of days. I will check the indicator light in the morning, and will have to just wait and see what dealer says next week. When I called the dealer he was aware that I had called BMW assist out as they had the paperwork faxed to them so they will now be aware they have been out twice now.
 
Remember that on my first Z, the Dension killed my battery. Just be careful that it is not that unit causing it as they may deny the warranty claim.
 
My 04's battery would go flat after just 1 week. Dealer kept giving me a new battery (3) each time I brought it in. The last time I told them that I didn't want it back until they fixed the problem. They put it on the computer for around 4 days until the problem finally showed up. It was a faulty Control Module Communication (transceiver). They put a new one in and have not had a problem since. It was under warranty fortunately, because the dealer had to call BMW to get ok to replace. Which tells me it was expensive! Get it fixed while in warranty!
Hope this helps.
 
billy that is my intention although warranty runs out soon, I'm sure they wont find the problem or will blame third party products. They do know what I am like though so hopefully will admit defeat easily and replace the battery or I will keep going back like you did.

Going to let it stand for 3 days over the weekend and Monday as a test though in a half hope it wont start on Tuesday.
 
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