High Voltage Decay?

Usually you will see green bars after a descent down a hill.

I suggest that you keep an eye on the traction battery SOC gauge to see whether it continues to show a big drop overnight. The gauge should not behave in that manner.

 

This may be a silly question but are you turning the car off when you park it?

 

it almost sounds as if something is draining it... or you forgot to power down.


if you're really curious, have toyota test it.

 

My thoughts too. More than one Prius owner has been fooled into leaving their Prius in Ready all night long.

As for blue bars, the control system on the Prius tries to keep the battery at the blue setting, which is in the middle of the charge range. This allows room for additional charging when doing regenerative braking.

All green is not a good thing. It's not bad either, but should only occur under special circumstances, such as regeneration from descending a long hill, or having the ICE run to keep the cabin warm.

Tom

 

That is very odd than. My salvage car sat for over 2 months with the car off and it still had 6 bars when I powered it back up.

 

Since the OP has a brand-new car, maybe the traction battery ECU has to go through a learning process to calibrate its SOC readings.

Or, maybe the 2009 behaves differently...

 

I think you are correct about the calibration.

Tom

 

A couple of things to keep in mind.

First, the gauge is not a "measurement instrument". It's an indicator. So take what you see with a grain or two of salt.

Second, the gauge does not "measure" battery voltage. It is operated by a computer, and it figures out what to display based on the charge it sees moving into and out of the battery. The battery is -fully- disconnected when the car is off. The other posters are not being suspicious of you or accusing you of incompetence. We have just seen lots of "newbies" leave the car on from time to time. Heck, I've done it once. Hey, only once!

Now, the computer uses lots of different things to calibrate itself, one of which is battery voltage. Battery voltage varies by temperature. Right there could be the explanation of the variance. The battery gets warm in use. It cools off overnight. The car will be doing the calibration routine often when new. As it learns, it "calms down".

Do be sure the battery vent is not blocked (right side of rear seat back). There is a fan in there, so don't panic if you hear it running from time to time.

 

My guess is either a one time Battery ECU re-calibration or the car was accidentally left on (really easy to do). Its not unusual for it to change by one bar, if it happened to be right on the edge, but losing three is odd. Keep an eye on it, if it keeps happening it should be looked at.

Rob

 

When I 1st got my 08, it would drop 1-2 bars overnight. It has since stopped doing this....not sure how long it took. I expect this is a calibration issue as mentioned above....The compter has to 'learn' what a full battery is. Only having 2 bars in the morning seems a bit extreme though, if that keeps up > a week, you might want to have it checked.

 

I have to go along with kayak_hauler -- my 08 behaved the same way for about a week. We had the car three days before we ever saw green bars even though we had what seemed to be a lot of regen.