Question about traction battery

This is my first Prius, so maybe my question has a well-known answer - I can find it though. I only got my 2010 Prius on July 24.

It seems that When I start the car first time in the morning, the display shows that the battery has low charge level, usually 3 or 2 bars. This is the case even if it has been nearly fully charged the day before. Is this normal?

An additional thing is about the 'immobilization light'. I understand that it would flash when you power off the car. I thought it would flash for a while and goes out, but it appears to go on flashing all night long until I power up the car again. Is this the way it should behave? Doesn't it drain the battery?

Yingdat

Hi,

No this does not seem normal. The battery should normally be the same SOC as the night before, maybe one bar less. Are you sure you have both keys far away from the car at night? But the traction battery is disconnected when you power off and only the 12v battery would get drained by any electronics at night.

I'd recheck all this and visit your dealer if it still happens.

3PriusMike

Not sure about the traction battery, but as for the immobilization battery, yes that light will flash all night. I think the battery drain from that is probably fairly negligible.

Thanks for the info. I already took it in once but the dealership just brushed me off. I guess I have to insist.

I suspect this also has something to do with my lousy MPG. It's only in the 30s, and I hardly ever get outside the 'eco' range.

Yingdat

Thanks for the info. It's good to know for sure.

yingdat

I agree with 3PriusMike. If the immobility light is flashing, I believe that indicates you've turned the Prius off completely, so there shouldn't be anything draining the traction battery at that point. You can leave the Prius for a week, even with the SKS scanner on apparently (I don't have SKS), and the battery won't be drained, so there definitely shouldn't be anything noticeable happening overnight, assuming you don't generally leave a door open.

Something's not right. The usual reason is that you actually haven't turned the car off! It will use the HV traction battery to keep the 12V battery charged, and as the traction battery gets low it will start the engine. The Gen 2 had about 300-400W of electrical load on the 12V system when fully powered up, the HV battery's nominal capacity is 1.3kWh, so you can see it would need to run a bit to keep the HV battery charged overnight.

Just taking the keys out of the car doesn't turn it off. People have been known to drive them all the way to the destination, turn the car off, then discover that they had the wrong smart key and not be able to turn it back on. You have to press the power button.

Make sure you actually lock the car by pressing the sensor lines on the doorhandle when you get out. This will either lock, or emit a beep to tell you that it can't lock. Find out why.

Mike, I'm curious why you say to "make sure you actually lock the car...". I seldom lock the car and don't see any need to where we live. Is that for security concerns?

I can confirm the other replies about the battery. Even after a few days, the battery charge level is always the as when I switched it off.

Consumption in the 30s in your case could only be excessive use of the A/C. At the start of a trip, the A/C has to work hard to cool the interior. If you only make very short trips (< 3 km), that could explain the 30s.

I also live in Austin, the A/C is on all the time, I make a lot of short trips, and my gas mileage was in the low 30's at the beginning. I normally drive in Eco Mode and use the Dynamic Radar Cruise Control whenever I can.

However, I now have over 600 miles on the car and the mileage has picked up considerably. It is now showing slightly over 40 MPG, with the same mix of short trips on city roads and slightly longer trips on US 183. I think the car has to go through a break-in period (and so does the driver!). I actually saw one trip (mostly on US 183) where the computer reported 50.6 MPG. I am waiting to see what the mileage will be next month when I drive up I-35 to Temple.

Just be patient, use some of the driving tips which have been posted on other threads, and see what happens.