12V Battery Not Charging

Parasitic drain

 

you'll have to do some testing. get a volt meter and check the voltage in the evening and then again in the morning to see how much it drains overnight.

are you driving much? it needs fairly regular use to maintain a charge, as there's a constant drain on the 12v when off.
did the shop give you any readings? fully charged should be close to 13 volts

 

You have something pulling excessive current after the shutdown. Typically its the hatch light because the hatch is not completely closed, a door left ajar, something left in the obd2 connector, an aftermarket accessory drawing current or even a keyfob left in the car. Measuring the current is the diagnostic, followed by fuse by fuse identification. Occasionally something built by Toyota is failing but that is not typical.

You should read 15ma-35ma after two minutes of vehicle shutdown. Series ma testing is the only reasonable test method short of a very expensive dc clamp meter made for the purpose. There are $50-$100 meters with dc clamps but they are very inaccurate in the low ma ranges.

All lights must be off before measuring ma. Some meters can only read 2 amps in series, use a 10 amp range if possible and then reduce the scale. Process is important because excessive current through the meter may blow an internal fuse. This a bit of an advanced procedure for some diy'ers from a good results standpoint.

 

When the care is "ready", what voltage are you getting at the battery?
Should be 14+ volts. If you don't, you could have inverter problems.
If you do, they check the other things in the previous posts.

Did you/they clean the terminals before installing them on the new battery?

 

Maybe.
Or maybe it really is not charging up to full.
Or maybe the battery has gone bad.

The voltage needs to be checked while the car is in "ready" mode.......running.
And the battery needs to be tested (he didn't really say that it was).
AND......if it sits unused for long periods, over 2 weeks, he needs a tender.

 

What kind of battery did you buy? If you bought an Optima Yellowtop you didn't buy a real 12v, you bought a fake one and that's where the problem is. Optima is no longer a legit battery maker, but a bunch of criminals that re-sell returned batteries that they claim just needed recharged even when they're clearly defective.

 

then i can't see what else could possibly be wrong