battery charging problem
 

I did do a search on the forums and I know my battery is the culprit - but I dont know why :)

Car details:
2005 MT - all stock - no aftermarket alarms etc
New battery (4 months old)
Cranking amps slightly below spec of 640 CCA - mine is 575
<edit> Mileage 61000 miles </edit>

Problem:
Car would not crank at all. When I turn the key - all I hear is a click. Took out the voltmeter and measured voltage across terminals - 12.5 V. Measuring again across terminals while turning the key to start - 11.4 V - I heard that 12 V minimum is needed to the starter. So thats bad. Tried to jump start - no go - push started the car and it started fine. Then drove it around for 6 months without incident. Then it failed again with the same symptoms and I chucked the old battery.

Got a new battery (the highest cold cranking amps they had was 575). Started fine although takes a little longer to crank (prolly the battery cold cranking amps rating). I went through a New England winter with temps of 0F etc without the problem recurring. I checked that with the car running I was getting 14 V across terminals - so alternator is presumably doing its job.

Then problem showed up again today. I drive the car everday - its my only car. Battery again cannot supply enough voltage. I am charging it now but am wondering why is the battery deteriorating like this. Both batteries behaved like this - although the old battery was 4 years old. This one is only 4 months. And I am not sure why jump starting didnt work either.

Anyway - trickle charging it now - is prolly going to run after that - but I hope it doesnt fail on me in a snowstorm in the middle of nowhere :) I'll re-check the voltage across the terminals with the car running after it starts up.

Throughly clean all the connections and make sure they are tight.

when the problem happened with the old battery - I did clean the terminal and connectors and that didnt help. The problem occurred again.

With my old battery, I also took it to the dealer and they said they checked all the wiring connections and could not find a problem. So they cleaned some air flow sensor and charged me 100$ without telling me - buggers :mad:

in short the terminals are still clean - not sure about all the wiring tho from alternator etc to battery. Maybe I should replace the wires and see - but I would like to see some evidence first though of some problem with those wires. Not sure what to look for.

Maybe water or something is getting to some wires and causing problems... dunno how that would happen - I havent washed the engine bay or anything.

Everything else being equal it appears that you may have a phantom drain somewhere. Trunk ajar (and therefore interior light)?

Of course it could be the alternator-to-battery harness, but that's a pretty rare issue.

Cleaning the MAF is a good thing, but it's a job you can do yourself for the price of some electro-contact cleaner. So you were the one that got cleaned on that one. :(

no i lock the car and blinkers flash and lights darken inside - its possible i missed something - not sure. I have noticed one thing though, sometimes I cannot open my trunk lid with the keyless system - something trips and I have to reset the switch in the glove box before I can open the trunk keylessly. This info is neither here nor there - but thought I'd throw that out - since thats weird too.

yeah if only they had told me before they were going to do it - so they have lost my business.