Help! Something is draining battery

welcome!
you need to get the trouble codes read at a dealer.

 

I presume the OP is referring to the 12V battery and not the hybrid one......

The most common cause of 12v drain is a light that is on while the vehicle is parked (glovebox, trunk, etc), or some aftermarket system (security, radio etc) that continually operates even with the vehicle "off".

It is possible that the 12V is simply really weak and if over 7 years of age, failure of the 12v itself should not be overlooked as a potential cause.

 

Are you sure you don’t have one of these hiding under the bonnet?


iPhone ? Pro

 

'have even experienced the same issue when it's fully charged'. see the original post.

you can put a meter on the battery to see if the drain is higher than toyota's standard value.

 

not that i know of, is it aftermarket?

 

if you can find the power wire (maybe at one of the fuse boxes or the 12v, just remove it.

 

Cut it out of there!

 

Sure have seen a lot of these posts. It’s usually a bad 12 volt battery that will not hold a charge.
Our little AGM is really nothing like a full size battery performance.
I know it’s been “tested” which is meaningless to me as seen hundreds of tested battery’s fail on this site at the worst possible time AFTER A GOOD TEST. . I can say for sure the charge rate on our cars is much different than full size battery cars.
A new Prius battery will live at around 12.5 or lower while my full size cars live at a much higher rate.
That alone is not good.

Here’s the deciding factor......if you have had to jumpstart it then it needs to be replaced. IMHO.

If your in love with your battery the investigation is easy. Get a dc ammeter and lift the ground wire off the battery by unbolting it from the chassis and put the ammeter in series with that ground wire and the chassis.

Report Ma readings back here.

 

Mike I suspect there are two problems. The "screen & dash" going dark sounds like the combination meter is failing. The idiot lights are tripping codes. Please have them read as the car is trying to tell you what is wrong.

 

If I remember the red car light lights when there is a door not closed properly, is this the red car light you mean?

 

Sounds bad.

You need a voltmeter. And the codes read. With voltmeter next time that happens shut the car off and open the hood and check the battery volatage at the jump points. Then with car still off turn on th3 headlights and measure again and see how low the headlights pull that battery down. Then turn off the headlights and turn on the car and measure again. Report those 3 back here.

And you need alll the codes read. Stop clearing the codes and get them read. The car is telling you why it’s unhappy. I suspect you have multiple issues probably bad hybrid battery and combo meter.

Code readers available:

Android code reader app need app and Bluetooth obd
Scan gauge x gauge
Dxdiag
Mini vci uses so laptop

 

Let us know if you have a multi meter. It's worth buying if you don't.

I can walk you through a parasitic draw test when you're ready. It's easy and as long as it's not an intermittent issue, which it doesn't sound like it will be, it will find your problem.

Moto G Play ?

 

The OP doesn’t have a parasitic load on the battery anymore now he’s saying all kinds of lights come on after new battery install.

 

2005 T3
I had similar problems and eventually my 12v battery died but Eurocarparts replaced it under warranty ( Bosch S4 05 (S4 019) 40Ah - 2 years old , 4 year warranty)
So if did some further checking and found the parasitic drain with everything shut & locked was about 0.07A which seems rather high, tried a few things and eventually tried pushing the button to disable the smartkey system under the steering wheel a few times with the following observations:-
- I dont have the smart key system as far as I know
- according to the manual, the button should be latching but it does not
- parasitic drain now seems to be about 0.02A (much better)
- the alarm system dashboard light now behaves differently, it used to start flashing every few seconds after locking the car but now it glows with a slight dimming every few seconds for about 30 seconds and then changes to flashing every few seconds.

No idea what is going on here but keeping an eye on the battery charge state, especially if I dont use the car for a while.