Battery dead after four days

It's a real long shot, but have you checked for the dreaded "Penny Wedged In The Power Outlet" problem?

http://www.priuschat.com/forums/how-to-avo...d-a-vt3965.html

It would probably blow the fuse right away, but you never know.

 

Geoff,
Is it remotely possible you left the car in ACC or IG-On? Maybe powered off then went to either of these modes to check something, listen to the radio, etc and forgot to power off when you left?

 

most modern automotive batterys don't ever recover from a complete discharge. The older lead acid batterys would but the new ones us a larger amout of antimony in the plates instead of lead and this is the problem. It creates a chemical barrier to the transfer of electrons. I could get more technical if you want but that is essentially the bottom line.

 

i agree with frank. a battery as small as the 12 volt battery in the Prius i would think would be very weak and not withstand many discharges.

as far as your trickle charger starting the car, that wont happen. 8 amps at 12 volts is 96 watts. that aint enough to do it. add the resistance of a dead battery and its gonna be worse. realize that power output isnt that cut and dried but it still gives you a general idea of what is needed. to jump a car with a dead battery, you are looking at various levels of charge ranging from roughly 150 amps for short duration charges to maybe 20 amps for 15 minutes of charge. keep in mind that temperature of the battery also plays a part too.

to boot an average computer can take up to 300 watts if you have an optical drive and multiple hard drives with a CRT monitor and computers use very little power when compared to nearly every appliance.

 

In the condo where I live, the heated underground parking is secured, so the only driver who routinely sets his alarm is the Mercedes S-class owner. I have noticed that some owners are away a LOT on business, and they have rigged those tiny fully automatic trickle chargers to their car. They're very small and only put out about 1A, but if you're gone for 2 weeks or a month, it will monitor the battery and automatically keep the float charge on the battery. They are guaranteed not to overcharge either. After hearing these horror stories of dead batteries, I may invest in a trickle charger. Companies that make them: Chicago Power Tools "BFC-12," Guest "Battery Pal," Vector Manufacturing "Smart Charger." You can find these neat gadgets at (http://www.automotive-battery-chargers.com). Hope this helps!

 

that is a good idea. modern chargers have electronic circuitry that prevents overcharging. for long periods of inactivity that might be the solution although that wouldnt help the traction battery.

the traction battery will hold a charge much longer because it has more charge to hold but it wont last forever.

does anyone know what a max recommended storage time for the traction battery would be?

 

thanks for the info. 6-12 months is a long time, although i couldnt see me parking my car long than a few days if that. it will definitely cover vacations and normal trips though. i have friends who live in alaska and new mexico and they would have occasion to let their car sit for up to 5-6 months.

on the OP, if its just a battery problem then no problem. but seems pretty unusual that a car would drain the battery in such a short period of time without having other problems.

 

When you put your foot on the brake pedal, was the brake pump running, even if it might have been slower than normal? If so, you could probably wait until it reached full pressure, then try powering on.

Another idea. Press lightly on the brake pedal, only enough to trigger the brake lights. I believe there is some margin before it will kick in the hydrolic pump.

I also agree, the dead battery itself was a big load too.

And, unless you have the mod, adding a solar trickle charger connnected to the power outlet won't help, as it is disconnected when car is off.

Is it possible you left the headlights on? It only shuts off if you power off the car, then open the driver door.

 

After my post, I verified that it is possible, though tricky, to apply the brakes just enough to allow power on to Ready, but not operate the hydaulic pump.