2008 Prius not Starting

The 12V battery in the Prius needs more than a quick start to recharge. You need to do one of two things: 1) Put it on a charger, or 2) Run the car for several hours.

The jump got it started, but the charge level was still low. A few days later there isn't enough juice left to boot up.

Tom

 

When the new battery was installed, maybe that battery was not fully charged before installation in your car.

If the battery is discharged, you may need to leave the car READY for several hours before it will be fully charged. This is because the Prius 12V bus, operating at ~13.8V regulated by the DC to DC converter, runs at a lower voltage compared to traditional vehicles where the alternator may provide 14.4V-15V when the battery is low.

 

Hi Libby,

Assuming that the replacement 12V battery is good, that it becomes fully-charged after you leave the car READY for a few hours, and that you make sure all cabin lights are off and the car is locked when not in use - then I would say you can move to a weekly cycle, where you make the car READY for 30 minutes at a time.

 

The car runs the '12V' bus at over 14V when it thinks the auxiliary battery needs charging. This can be observed in the 'Vehicle Signal Check' diagnostics screen (see here for how to access this - scroll right down).

My recollection is that the storage instructions, which I was only reading yesterday, say that the car should be left in READY for half an hour every two weeks.

 

Are you sure your not leaving your doors ajar? Perhaps the rear trunk light is on and draining your battery?

 

There are two interior light switches, the overhead one and the one in the hatch area. They each have three positions. OFF, DOOR ACTIVATED, and ON. You have to make sure they are in OFF or DOOR ACTIVATED. The one in the hatch is probably the one in the ON position. It's hard to see the light unless you really look from outside the car.

This is the most probable thing draining the battery.

Of course it's also possible the "new" battery the dealer installed is also "bad".

 

Yeah, it kinda smells as though someone is not shutting off the car properly. *Always* lock the car; if any common battery-draining things are amiss the car will give a long warning beep. Of course if the 12V battery has been completely drained once it may already be permanently damaged.

 

If you are going to park your car for weeks at a time, I would think seriously about using some sort of trickle charger to keep the battery topped off.

Tom

 

A trickle charger is a small battery charger. It provides a "trickle" of juice to keep the battery topped up. You plug it into the wall and attach the other cables to the battery or jump points under the hood. After that you can store your car indefinitely without running down the battery. You may have other problems, but it won't be the battery.

Tom

 

Again, locking the car will warn one of such situations. It's a good habit to get into regardless of where you park. It has twice saved me from killing the battery while in my garage.

 

Glad that your problem is solved for now.

If a door or the hatch is ajar, locking the car and hearing an unusual beep will warn you of the problem. However if a cabin light is turned on using the pushbutton switch and left on, then locking the car will not give you a clue about the light being on.

 

Locking the car won't help with the map lights. You have to watch out for those.

Tom

 

Good points. So modify the advice: if you're going to have someone else start or use the Prius for you, first make certain yourself that all of the light switches are set OFF, and then sternly charge that person to leave all the interior lights OFF. And, to always lock the car :_>

 

Richard's lock-the-car advice is sound. I always lock my Prius. I never routinely lock any other car where we live, it's simply not necessary, but with the Prius it's a great way to make sure everything is shut, powered down, and the fobs removed.

Okay, let's be honest here, how many of you have walked away or tried to walk away with your Prius still on? I have, on more than one occasion, wondering the whole time why it was beeping at me.

Tom

 

Turn off the smart key when you park for extended periods. There is a button under the steering column. Whenever I park it for a while I do this, and no worries yet.