Ugh, I think my 12V battery's dying

so i guess you just ran it down that time?

i didn't want to have to tell you to shut up, and that you CAN replace the battery yourself.

 

Did the tech charge the battery before testing it?

It would be interesting for you to measure the battery voltage now, and see if you also read 12.6V; or a lower amount.

 

you drove it to the dealer
so the voltage Will be higher because its just been charged by your car...

you need to disconnect it for 1 day charge it and then when its fully charged leave it for 12 ours
measure before and after those 12 ours!
when its 12,7-13 volts before and below 12,5 after 12 ours then is defective

 

Now it's easy: time for a new battery. Don't kill the new one :_>

 

After reading the previous posts I feel it necessary to debunk the myth of the replacement of the 12 volt AGM battery in the trunk of the Gen II Prii. Not only is it damn simple, it does not involve the removal of the fuse box or anything in the engine compartment.

My apologies in advance for the length of this how to...

Basically, anyone with interest in doing this themselves, with or without prior automotive experience, can do this if they follow these simple instructions.

First, make sure the car is off and take the key out of the dash. For those of you with smart key, move your key out of range.

Next, open the trunk and pull up the mats covering the back area behind the rear seats. You will see on the right, a semi triangular shaped cover that should lift up with minimal effort. You may have to wiggle it some and apply some force to get it loose from the rest of the interior.

Once the cover is removed, you will see the battery. On the left is the positive side with a red cover being held in 3 separate places. Gently pry these off with a small screwdriver and lift the cover off. On the right is the negative side of the battery. You should ALWAYS remove the negetive battery cable first. Period, regardless of what electrical work you are doing on your car/hybrid. Use a 10mm socket or box wrench to remove the nut that tightens the cable on the battery post. Once you have removed the negative cable, I like to wrap electrical tape around it to keep it from coming in contact with anything metal in the trunk area while I am working.

With the negative battery cable removed, you are now ready to remove the positive cable. Use the same 10mm socket or box wrench to loosen the nut on the cable end. The terminals on the ends may need some slight force to work them off the posts, but once the nut is loose, they should come off without too much trouble.

After you have the cable ends off the posts, pull the battery straight up and out of where it sits. It's pretty heavy, 40lbs or so. Once you have it up and out, use a pair of pliers to remove the vent tube from the top of the battery, you will save this to put on the new battery.

Installing the new battery is the reverse of removal. Positive cable first, negative last. Also, sometimes, small sparks will be made when reconnecting the negative cable to the post. Don't freak out though, there is not enough amperage to cause you or your car/hybrid any harm. Just push the terminal down onto the post, and tighten the nut.

Replace the interior pieces you removed, and thats it, you're done. Pat yourself on the back for a job well done and thumb your nose at the dealer after having saved yourself a couple hundred bucks.

Cheers,

Michou

 

I hope you didn't pay much for the "load test" that your dealer performed since that was proven to be worthless.

At this point I suggest that you either replace the battery yourself, or else go to a dealer and say you want the battery replaced; you don't want them to waste their time and your money by testing the old one.

The installation process really is not that bad; once you have the battery in view it should become obvious what you have to remove to take it out.