Battery keeps dying!

[Nissan2014pathfinder]

I have a 2014 Nissan Pathfinder and last night the battery died. Before this happened I noticed my RPMs jumping at idle. Was driving it and the battery charging light came on and then it would not let me accelerate and died. It also threw a Code P0507 - idle air control system RPM higher than expected. Pulled the battery out and when to get a new one and was told the battery was completely dead. Bought a new one installed it code was gone and voltage was good. Drove it home and parked it and the battery light and a break light was still on. Figured it would go away and needed time to reset its self. Got up this morning to try and start it and voltage was low at 9.9 and eventually went down to 8 and then died. Any suggestions or ideas?

[Citron]

Alternator.

[adamzan]

Definitely sounds like a bad alternator. I wouldn't suspect corrosion on the terminals on a 2014 in Texas. But it wouldn't hurt to check them. Possibly under warranty still?

[Bunchie]

An easy way to check the output of your alternator is by starting the engine then once running, remove the Positive battery lead. If the engine dies, your alternator is shot. Truly, the only reason current vehicles have batteries is to simply spin & engage the starter motor.

[Slartibartfast]

No. Don't do that.

 

The battery doesn't just store power for the starter motor. It also filters out the noise the alternator makes, noise which the endlessly multiplying electronics in modern cars may or may not be able to deal with. This may have been a valid test on cars of the 60s and earlier, but I wouldn't do it to anything fuel-injected. There are too many expensive things that could go wrong.

 

+1 for a failing alternator. The battery light on the dash isn't a trouble code that hasn't cleared yet, it's a sign the alt isn't charging. A buggered alt can also make the battery run down overnight, if a diode is shorted, though it sounds more like the battery just ran down as you drove home and you got lucky (the lights and electronics didn't discharge the battery enough for them to quit before you got home). Get a new alt in there and/or get it on a charger ASAP, lead acid batteries don't respond well to sitting around discharged for extended periods.

 

Also +1 for making it someone else's problem if it's still under warranty.

[RedPath88]

If its under warranty, get it in asap and keep the battery charged until you can.... if it's not then take them both out and have them tested (battery needs top be as fully charged as possible for proper testing)... at more than one parts store, because some times a given parts store employee may not know how to properly setup or read results of their machines (this is mostly about alternator testing.)  Then go from there.