Hybrid battery looses charge.

Say what???

 

Did you add a high voltage solar charger? The PV panel on the stock Prius is only used to power a ventilating fan. It does not charge anything.

As for lower SOC when parked at school, there are two likely causes:

1) Hot or cold parking lot, which reduces the effective SOC.

2) Leaving your Prius in Ready. This will run down the HV battery, as the ICE will run only enough to keep it partially charged.

Tom

 

katiesdad, are you *really* sure that the car is off? Maintaining 2 bars is exactly what the car does when it is Parked and ON. Lock it every time you leave it; the absence of any warning beeps will assure you that it is off.

As other wrote, if it really is off and this still happens then yes, there is something wrong with the car. Take it to a different dealer for diagnosis.

 

Photos won't help - we believe you. Get thee to a different dealer, pronto! Something is draining the HV battery while the car is off. This is not normal or good.

 

Are you sure EVERYTHING is turned off when parked?

 

My new 2011, which is not even a month old, has done this a time or two, and yes, I am almost 100% sure everything is off.

 

The only way to be certain is to lock it; if anything is ajar or certain lights left on it will complain. Do you always lock it?

This can be surprisingly easy to overlook. Twice now, locking mine has saved me from a drained battery in my garage.

 

It's not unusual for the SOC to change from one use to another. The SOC reading is just an estimate of the charge remaining in the HV battery. The computer calculates a best guess based on a number of external factors, since there isn't any way to actually look at the charge in the battery. This means that the estimate will vary a bit from time to time. Temperature can make a big difference.

What you want to watch for is a pattern. If the SOC consistently drops you might have a problem. Likewise watch for erratic swings in SOC while driving. Failing HV batteries will often swing back and forth rapidly from full to empty, even when driving at a constant speed on a flat road.

Tom

 

The solar roof panel doesn't charge your hybrid battery, it's only used to run a small fan for the interior. (Hence, the packages name. Solar powered ventilation system.) The fan isn't hooked to the battery at all, it's powered by the sun only, so there's no need to worry about that.

As for your battery draining, I'm sure you push the power button before you get out of the car to turn the system off. Correct? The Prius' SOC is comfortable at around 6 bars, that's where you'll see it most of the time. If you leave your car with 6 bars on the battery SOC (state of charge) indicator, and come back with only 2 bars, that's not normal.

Since you have the solar roof ventilation system, that means you also have the A/C button on your keyless remote. Do you ever press that button? That could drain your battery for running the electric A/C.

I think you should really read more about your car, or tell your dealer that their full of crap. The solar panels don't charge the hybrid battery, their not even connected. Plus, don't worry about using the fan when shutting the car off. It's powered *only* by the solar panels.

 

is it working okay now? good!

 

Not normal but also unlikely it's really doing this that often. I'd recommend you start recording the time you turn it off and on and the bar difference. That's the only way to quantify this. You can then bring that to Toyota if you need to. 1 bar shy of top should not drop to 2 in the period of a day, it should take way way longer than that.

 

I have a guess.... When you get to school do you do some driving on the battery alone the last part of ypour drive? Maybe a 1/4 or 1/2 mile of parking lot school road driving maybe with the ac on?

I have noticed if I only use the HV battery on the last part of my trip the meter is slow to show it getting low, then I turn it off. Next time I start it up the guage shows 2-3 bars left and I know thats right because I used it up driving around getting my mail and driving through the parking lot without using the ICE.

plus there is no way the battery is fully charged when you park it, Do you mean 1-3 bars from the top? The only way to top it off is a very long downhill drive like decending a mountain.

 

How do you guys remember how many bars your battery had throughout the day?

 

Hi Kd7,

Remember, the Prius runs in a what we call on here stage 1 of the warmup cycle for the first minute after made ready.

In this mode, the engine runs, but it provides little to none of the motive torque. The hybrid battery is providing this torque. If you have only moderate accelleration, or uphill travel in that first minute, the hybrid battery will quickly change its state of charge downward during this first minute.

To be sure you are getting such a large change in the hybrid battery state of charge, you need to observe the state of charge the instant you turn the car back on, and compare it with the state of charge the instant you turned it off. If you wait even 15 seconds, while your rolling along to observe the state of charge, it could change a bar in that time, 2 or 3 bars by the end of the minute.

Its my experience one bar change in SOC is normal stop to start. Which means 3 or 4 bars drop stop to the end of the one-minute stage 1.

 

I just use my brian to "remember".

 

Off topic but what kind of driving are you doing if you've already put 24 fuel-ups on your Prius since January of this year?

 

Did we ever find out if this was the issue?