I have an 08 G35 sport.....I have owned it for less than a month. Went to use it a couple days after purchasing and the battery was dead. Not knowing how old the battery was I simply replaced it. drove it a few times and it was ok......the car sat for a couple days and the battery is dead again. No warning lights, no dim lights, everything is functioning....

Help please? I have done some reading and this seems to be a reoccurring problem.

Thanks,
Jet

 

Did you clean the terminal posts THOROUGHLY when installing the battery, down to clean shiny metal? Do you have any aftermarket electronics including stereo? Do you have ANY electrical components inside the vehicle that are currently non-functional? I would start with all those items as well as checking for voltage with the engine running.

+ to - with the car running should be 14.5vdc

 

Thanks for reply........stock everything and everything appears to be working ok. I watched a video that showed the trunk mounted CD player was the culprit.. and taking the cartridge out was the solution. Tried that ! Battery still died...

 

Sorry.....and yes to cleaning the posts

 

What about operating voltage?

 

Just because you buy a new battery doesn't mean it's going to work as intended! Drive your G back to where you bought the battery and have them check it, sitting for a few day tells me it could have a dead cell! If the battery isn't the issue have them check your charging system, alternator s/b putting out 13.5 volts...much less replace it! Is your drive belts tight enough or do you hear them making noise? How about lights left on when everything is closed up and shut down...under doors or trunk? Lots of things to check...Gary

 

Yep, like checking to make sure your brake switch isn't broken thus leaving your brake lights on ALL THE TIME...

 

^^^^^^^

What he said!

Test battery with a battery hydrometer



Measure alternator output voltage with a digital multi-meter across the battery with the engine running.



Put the meter in series with the battery cable to measure any possible current draw with the engine off.

Telcoman

 

Check all the connections like everyone mentioned and the battery voltage with the car running a load.

You can do a parasitic draw test by connecting a multimeter in series to the negative cable in amp mode. If you have high amperage stary pulling fuses to see what circuit makes it drop. You can also test each fuse for volage and then calculate how much draw there is.