toyota electrical problem

[guest]

Toyota Avalon, 2008. Battery discharges when car is shut down. No known lights or accessories on. Recharge and start, same problem after shutdown.

[carriedi]

how old is the battery? An older battery will show it charges up on a charger but if won't have the amp capacity to start the engine after a short time.

If the battery is pretty new then I would look for a draw on the battery. Make sure you don't have a hood switch that the computer monitors and shut everything off. After an hour check for any draw on the battery. You can measure voltage differences on the fuses or you can hook up a amp gauge in series to the battery. If you can get an inductive amp gauge, you could use that too. see what amp draw you have on the battery.

Because amp draw sometimes take a while to show up, the in series gauge works best for me. I use the power probe Hook to look at the draw. 25 milliamp is a good draw that would take a long time to kill a good battery. Depending on all the electrical load it shouldn't go over 50 milliamp. Over that I would try to locate where the load is coming from

*also, just thought of this, you can use a thermal imager to look for your draw also. a fuse or relay that has current running through it will be warmer than the unused components around it.