12V battery fully drained, won't jump start either

I believe it's 3 years. What does your warranty booklet say?

 

Is it possible you left a light on over the weekend?

 

A bunch of that quote is installation. If you use one of the 25% off coupons that come in the mail, and do the install yourself, the price isn't all that bad.

 

Been there, done that! Best rule of thumb: always lock the doors, so lights go out.

 

20% Off
Any Part We Have In Stock (excluding accessories)
​

Toyota models only. Please present coupon during write-up. Over-the-counter only at parts center. For more information on this special or any other parts special here at Chicago Northside Toyota, please contact our Parts Department at 773-728-4474. All prices plus fees and taxes. Picture may not represent actual product/service.

Offer expires: 04/15/2013​

 

TRUESTART GENUINE TOYOTA BATTERY​

Meets Today's Severe Starting Demands, 24-Month, 100% Replacement Warranty, 84-Month Limited Warranty, 60-Month Proration

$98.76 Sale Price​

Toyota models only. Please present coupon during write-up. Over-the-counter only at parts center. For more information on this special or any other parts special here at Chicago Northside Toyota, please contact our Parts Department at 773-728-4474. All prices plus fees and taxes. Picture may not represent actual product/service.

Offer expires: 04/15/2013​

 

Or use led lights,takes way longer to drain

 

This is a major reason I swapped all the interior lights to LEDs.

 

Just lock your car when you leave and make sure all the lights are off. That will solve all this battery problems

 

I set all the "convenience" lights to be completely off (won't turn on when you open hatch or door).

 

Unless I'm mistaken, for the Prius you don't want a battery that "meets today's severe starting demands". Batteries designed for starting cars have the ability to deliver the very large amount of current required for a short time. In trade, they don't tolerate a deep discharge and are effectively ruined by as few as one, and at best just a very few. Prius doesn't use the battery for starting the engine, but just booting the system, so it doesn't need to deliver the very high current of a standard starting battery. And you'd like it to survive a deep discharge if that were to happen. What the Prius needs instead is a deep-discharge battery more akin to the ones used for golf carts, wheelchairs, and outboard trolling motors.

 

There was another incident like this. The jump starting port under the hood is peculiar in that it is only conductive (metal) on one side. At the same time some jumper cables only conduct from one jaw.
Unless the battery has an extraordinary internal short just about anything should be able to provide the current to get the Prius to ready state. Leave a door open and fiddle with the jumper clamp until the dome light lights. You should be able to proceed from there.

 

Thanks for the tip about the cable being conductive on one side only. Solved my problem!

 

I have had a similar experience some weeks ago, when I got home after one week trip I found my 3 years-old Prius battery dead. Luckily, during last winter I had bought a smart charger specific for AGM batteries (a CTEK MSX 5.0 unit), I have let the charger working the whole weekend desulfating the battery, and apparently the issue with the battery has been fixed, since now I am consistently reading 12,7 V with the multimeter, when I check from time to time.
Furthermore, since when I bought the charger I left connected to the 12V battery the CTEK proprietary quick connect plug, I just lowered the rear seat and connected the charger through the plug, piece of cake. That's because the trunk did not open with the 12V battery dead...

 

There *is* a way to open it but you have to crawl in from the back seat and open a trim cover to access the mechanism.