went to start my car to come home from work today and the battery was almost completely dead (10.5V), just got a couple slow turns out of the starter. jumped the car and it started right up, kept working till i got home (alternator is working; when running battery voltage was 14.4V)

i checked the battery voltage when i got home right away; it was 12.6V and the car started up again when i tried to start it right after shutting it off, but when i tried to start it 5 minutes later it was dead already, sitting at 10.5V. when i checked it again 2 hours later it was still 10.5V, so its not a direct short but it can drain the battery very quickly.

no fuses are blown, I did not leave any lights on, the battery is 3 years old and has never failed to start the car (except when my main relay went bad)

any ideas on what might be wrong with my car?

 

What type of battery are you using? Reason I ask it could be something dealing with the water levels in the cells. Sealed batteries dont have this problem. (thank god!!!) If not and you say your alternator is putting out 14.4V , then I would look at replacing the battery.

 

i think it's a duralast, and there seems to be no leaking around the battery

 

when i parked at work this morning 2 hours ago i immediately disconnected the battery and it was reading 13.1V. i just checked it at it is still up at 12.5. 0.6V seems to be a predictable amount for the battery to settle after being charged. I'll check it at lunch but I dont expect it will have dropped much more, so it looks like it might not be a problem with the battery

 

Hey man unless its a dry cell battery like an optima battery, usually there two rectangle caps on the top. Thats where you would fill it with water if need be. Now if it continues to drain that might be your problem otherwise it could be an open circuit somewhere in the vehicle, but I doubt it.
Ive had optima batteries (2 of them) in my vehicles since 2001. They last 5+ years with no maintenance and none of that corrosion crap that can hinder a solid connection.

 

Sounds like the battery...or maybe a bad ground somewhere. I know the main battery ground goes underneath the battery tray. It might be corroded, but if its a duralast battery just take it to autozone and theyll check it for free(i believe) and if its bad it might still be under warranty.

 

Your battery is gone....

Same thing happened to my Girl's Lexus....Would start right up after a long drive, but if you leave it for couple hours DEAD....

Take it to Advanced Auto Parts...they will check if its the battery or alternator and will replace it (install) for free if you choose to buy from them....

We ended up getting the Autocraft GOLD battery for her Lexus which was 108 bucks - 25% discount which is going on....3 years free replacement warranty + 84 months prorated warranty....

BTW I just saw you have an RL....the original TL battery has a 100 month warranty (8 years), so you can take her in and get it replaced at the dealership....does the RL do the same ?