12v Battery Keeps Dying

Welcome to PriusChat! You've certainly come to the right place to find answers. You might update your info. so that folk can see where you are, and being that the cold season is just starting (here in the NE USA, anyway) always remember that the AuxBattery (12V) works on a chemical reaction which is very dependent on temperature, so as the temps. drop, they don't perform as well. That, plus the AuxBattery is rather small, which is another disadvantage. It sounds like the battery is being drained (light being left on?) plus the SKS system (if fitted) can drain a weak battery (but can be temporarily disabled). In fact I replaced the AuxBattery on my 2009 Gen II 2 years ago (at the time it was 6 years old (normally their life is around 4 to 5 years) and the first symptom I noticed was the SKS started getting flakey! Good Luck, I'm sure you'll soon find the answer, but beware, PriusChat can be addictive!

 

Guessing the accident caused a hot wire to be grounded somewhere, the sks is the remote system that looks and unlocks the car, disabling it stops it from using the 12 v battery. Might be worth letting Toyota hook up their computer to see it it finds the drain.

 

You can put a multimeter in series between negative post and ground, see what the "background" amperage draw is.

 

Smart Key System - if fitted, information should be in manuals. The 12V AuxBattery is charged by the TractionBattery - see

(…skip to 17:00) - it's a bit long, but very useful in learning how the amazing Prius works (there are tons of videos on youtube if you have the time)

 

The 12volt battery, has no capacity to drain the hybrid battery.

If its showing the red triangle light, its likely a or some weak cells.

Scanning the car for codes, would help narrow down the problem.

A new battery draining? The only reason would be a short circuit somehow in the 12volt circuitry of the battery, and the system it powers.

Can you check some of the relays at the hood area, and see if you can replace them?

Also check the fuse at the 12volt battery location, in the truck for shorts.

Radio goes ? From your explanations here, this is a typical case of radio harness wires/contacts having partial contacts.

Unplug the connectors, etc, and inspect for corrosion, or an improperly connected connector.


Dxta

 

Normal parasitic loads would be around 20 milliamperes.

 

Exa

Exactly! In some cases I have seen with Honda cross tours, it even goes beyond that.

 

I like the snapshot you took on the Heath check. How did you do that on the laptop, pls? I have tried getting a snapshot like this from my laptop, but it just isn't working. Could you explain in some bit? Or did you snap that with your phone, refitted and posted here?

 

With older windows versions, alt print screen will capture current widow, place it in windows clipboard as an image file. With win 7 onward, google:

Windows snipping tool

 

Check out the P3030 for the HV battery. Click on the snowflake icon next to it and look at the block voltages that should be saved. The P3030 (iirc) says that one of the sensing wires is bad (most likely corroded through/broken off), but after 2 years of sitting, maybe just a really low voltage on some modules.

 

FFD = freeze frame data. = NO means there is no freeze frame data. If you look back at the screenshot you uploaded in post #10, 5 out of the 9 DTCs have a snowflake icon to the left of the DTC. This indicates that there is FFD. No snowflake = no FFD.

 

To reiterate a point he made in the video, the Prius is one of those cars (luxury??) he mentioned where you have to wait for it to "go to sleep" or quiesce (to use the technical term). IIRC it takes about 20 min, but give it 30 to be safe. During that 20-30 min some things shut down and you should see it drop at those stages. Remember, you need to have all doors closed (and your OP indicates you do not have SKS, so won't mention anything to do with that) and your timer starts from then. You therefore need to be able to see you ammeter without disturbing the car.

The reason I mention this, is the current you mentioned (1,65 A) is about what the car is when you open the driver's door, i. e. everything off but not quiesced. The first drop will drop to about 50 mA then then after 30 mins it should finally drop to the quiesced state of about 20 mA. If it is a little more but still under ~50 mA, I wouldn't worry.

Finally, if you don't find any circuits that are drawing unusually high after doing the fuse pulling, you need to consider what is preventing the systems from quiescing.

 

Ours was around 16~20 milliamperes, with regular, say every 15 seconds or so, spikes to around 40.

 

Your what and under what circumstances?

 

12 volt, monitoring milliamperes with a multi meter in series, all doors closed, car off for about an hour.