So...I've had some odd battery issues in the past few years, where they simply don't last anywhere near as long as they should. The original OEM battery lasted forever - felt like a good 4+ years. For that reason, I replaced it with a (seemingly) identical Infiniti battery - but that died in only a few years. After that, I have cycled through a number of aftermarket batteries, with no better luck. Most recently, less than two years ago, I dropped in whatever the best battery was from O'Reilly. Then, just earlier this year it also died. It was still so new that when I took it back to my local O'Reilly, they just handed me a brand new replacement. Now, in the past few days, it's been clearly showing signs of probably going - weak cranking on startup.

Everything works just fine once running, so it's likely not the alternator. Plus, the car is simply not old enough to imagine one of those going.

I could understand a bad battery. Or two. But this is likely the forth or fifth that I've had in the G37 - so that just makes no sense.

I will say, that maybe once or twice, while driving, I had an incidence where the lower lumbar bladder in the driver seat self-inflated and self deflated a few cycles. But that stopped, and I've never once noticed it do that while I'm sitting in the car, with the engine off. Still, obviously odd. Could that be doing damage while the car is sitting in the garage at night? Is there a specific fuse I could simply pop-out for those seat controls?

Where would I start to try and diagnose a mystery battery leak?

Any advice would be greatly appreciated!!!

Details:
'09 Sport, 7AT.
~40K on the clock
100% bone stock
Live in SoCal, so no severe weather to affect the car (nor battery).

 

hook a dvom to the battery and check what your amp draw is. imo, oreilly's is not known to sell quality anything. the original battery that came with the car from japan was probably a mitsuba or panasonic. they tend to be higher quality batteries but i have never ever seen those batteries being sold here in the states at the dealer or at any parts houses. the battery you got from the dealer is most likely manufactured by interstate which is a decent quality battery. batteries from oreillys and autozone or pepboys are just cr ap in a bucket. so you need to do a amp draw test on the vehicle before you start speculating that there is an issue when the cause can just be a shi tty battery.

 

Your assumption that the alternator is working fine may or may not be a good one. The job of the alternator is to charge the battery after it starts the car and maintain enough voltage to run whatever electrical components you have turned on, while the car is running.

It would not hurt to check the output of the alternator to ensure its charging correctly. Should have output voltage of around 14.8V. I would check it just so its one more item off your list and can help narrow things down.

 

Thanks. I'm hardly a battery brand expert. However, I will say that we also have a Titan with an O'Reilly's battery in it right now, and that thing has been cranking away for well over three-years now (knock-wood). But I'll definitely check the battery amp draw.

 

Yeah, you're right. I realize that I should confirm, for certain, that the alternator is working optimally, just to rule that out. Good extra advice, thanks!