Prius battery

I saw the same subject come up MANY times on this forum. I also left my Prius for a while (over a week) and nothing happen. If you have SKS, you can shut it off with the switch below the steering wheel to minimize the drain on the battery.

 

longest mine has sit was 2 days so not much help here. also, having ALL drains on the system is not wise. that means your remote control will not work, the theft deterent system, etc. all uses some power. electric interlock... well... dont really know about that one, but it does have a little key icon on the dash that does not run on solar, so it will be something.

surprised the battery drains in that short a time though. i have a friend who leaves his car sitting for up to 8-10 days at a time at least once a month. he has never had an issue.

he also had one of the first 3G Priuses. he got his in Dec 03. i am fairly certain that he has not had one single thing done as far as updates, SSC's etc. nothing....

guess he is just lucky. of course being on the road a lot means he has low mileage (i got my Prius 7 months later and past him in mileage last summer) but hasnt learned to drive his car well (he does drive like a nut though) since he only gets low 40's but his driving is 90% freeway at 70+ mph

 

Three things could have happened to drain the battery: leaving the SKS on (already covered here), leaving the auto shut-off headlight switch on, and leaving an SKS fob within 15 feet of the Prius.

Re the manual...turn off the SKS in the vehicle if parking for any period, store the extra SKS fobs at least 15 feet away from the vehicle (someone suggested on one of the threads to wrap it in foil...works great), and lastly, make sure the headlight switch is not on auto-off...turn it all the way off.

So far I've had no problems...

 

One more thing, well maybe. According to my owners manual, for my 06, 2 things occur after the vehicle shuts off, either of which, if a switch were to stick, then I think the battery would drain quickly.

1st, and almost immediate, it pumps coolant into the thermos bottle.
2nd, I think the owners manual said it occurs hours later, a pump comes on to sample the air to see if any gas fumes have escaped from the gas tank while parked. Don't know what happens if it detects any, maybe it logs it for a service tech to discover later on.

Just a guess. Could also be an interior light left on. My boys are good about doing that to me, but so far, no problems. As of today, I have 7900 miles on mine.

 

awesome! very reassuring!

enjoy the weekend!

 

What about cars that sit on the dealers lots? I would have to think that there are some that sit before being sold on the lot for more than a week without being driven.

Or do they sell them that fast?

 

i know the prius has a traditional low-voltage battery up front to start the motor and the high-voltage battery in back to run the motors, but if the front battery is drained from sitting too long, is the prius not smart enough to use some of the voltage in back to start up the car?

 

You are correct in your understanding that there is both a 12 volt battery and a high voltage battery in the Prius.

However, you are mistaken in your understanding of how the vehicle uses these 2 batteries.

The 12 volt battery is used for running accessories (SKS, radio, lights, etc) when the car is not in "ready" mode. More importantly, the 12 volt battery is used when you "turn the car on" to close a relay that connects the high voltage battery to the vehicle's high voltage system. The car does not have access to the high voltage battery at all until this relay is closed, at which time the car is then "on"

The 12 volt batter is NOT used to "start the motor" like it is in other vehicles. The Prius always uses the high voltage battery to "start the motor". Also when the car is in "ready" mode (so the relay is closed and the car has access to the high voltage battery), the high voltage power is run through a DC to DC switching power convertor and supplies the 12 volt system with just a bit over 13 volts, so the car is not running off the 12 volt battery at all. This 13+ volts also recharges the 12 volt battery as needed.

By the way, both batteries are "in the back". The 12 volt battery is actually further back in the car than the high voltage battery.