New car electrical/battery


#1

I bought a 2008 Acura TL (30,000) in Nov. (had it checked out by mechanic first). Battery continues to die even though it has been checked by dealer and AAA as being good. First time it had not been driven for two weeks (vacation), second time I sat in car listening to radio w/o engine (my bad), third time this week for no reason-not driven for two days. Dealer says with new electrical systems cars just die more readily. (Also called Acura and got basically same response and impatience from their rep.) Help!


#2

Nope, 2 days is nonsense, and just running your radio, even for a couple of hours, shouldn’t drain the battery. There’s something draining the battery, they need to spend the time to find it.


#3

If you haven’t had the charging system and the battery checked out yet for a problem then I suggest you do that. Something isn’t right. Have the battery also checked for a current drain while the car is parked. Most vehicles require some current drain to keep memories alive of around 15 to 20 milliamps. If the battery is in good shape with a full charge on it you should be able to leave the car parked for at least several weeks before the charge on the battery starts to go low.


#4

Yeah, I think you have a drain on the battery too. Pull the fuse for the seat heaters which have been a potential issue with them. Regardless, what they say about the battery, its still 3 years old and might be having a problem holding a good charge. Sorry but I just don’t trust those battery testers.


#5

Thanks for feedback. Back to argue with dealer.


#6

The problem might be with a computer/module that’s failing to go sleep thereby drawing the battery down as the vehicle sits. Normally after a vehicle is turned off the computers/modules go to sleep after about 45 minutes.

In the days before all the electronics that are found on vehicles today one would disconnect the negative battery cable and then connect a test light between the negative post on the battery and the negative battery cable. If the light illuminated it indicated a current draw on the battery. However, on todays vehicles this can’t be done because if the battery is disconnected it forces the computers/modules to go to sleep. So you won’t see a current draw if it’s caused from a computer/module that fails to go to sleep. Instead a current draw must be located without disconnecting the battery.

There’s two ways to locate a current draw on todays vehicles. One is to measure the voltage drop across the fuses. If a fuse is found with a large voltage drop it means that fuse element is hot and current is running thru that circuit. Another method is to point a low resolution infra-red thermal gun at the fuses. When a fuse registers a higher temperature than the rest of the fuses it means there’s current passing thru that fuse and into that circuit. With either of these methods it can be determined if a computer/module is failing to go to sleep.

Tester