Question: Prius Battery Information 101

Let's be clear, service techs usually know what they are talking about, service writers, the people most of us get to talk to, frequently know... the technical term is diddly.

It's a good idea to turn off SKS with the switch under the steering wheel if you're going to leave your car untouched for over a week. Also, the little 12V battery won't last 10 years/100,000 miles. If you have a 2005 original 12V battery, it's getting near the end of its normal life, particularly if you've drained it a couple of times.

And welcome to PriusChat! :welcome:

 

I wired up a VDC Battery Minder and leave my vehicles plugged in whenever they are not in use. Of course, I park in an attached garage, not outside in the weather.

I was having battery problems my first winter, the VDC appeared to cure the issue

 

My 2003 (146,000 miles) had the ORIGINAL 12V battery in it until 2 months ago. Things weren't acting right (seemed the ICE was running excessively in ready) so I checked it with what should have been a full charge in it after a long trip and the best it would read is 11.5 volts. I never had a starting or drivability problem but replaced it immediately with a "off the shelf" battery from Advance Auto Parts. It had the required vent tube and was the same dimentions except for the lockdown lugs on the bottom which I cut off with a hack saw. Fit perfect and is a larger AH rating than the original.

 

[ with a "off the shelf" battery from Advance Auto Parts. It had the required vent tube and was the same dimentions

Would you do a favor and list the number of that battery? The Advance Auto parts web site doesn't have a specific battery listed for the prius. Thanks in advance.

 

I second this, what is the number of the battery? This could help thousands of people instead spending large amounts from Toyota.
Please please please. I have a 1st gen so it's Toyota for me.

 

I wanted to see just how far the EM could take me... my battery was 1 bar from half and it drove me about 2 miles at ~55mph =) I needed to know how long it would take the car to die in a controlled test instead of having it die in the middle of a desert or some god-forsaken place ...

 

Cool!

Next time, shift into "N" and let your speed fall to 20 mph and then coast to a stop. Pull the fuses for your headlights and minimize all other electrical loads. Then resume your speed at 20 mph. This should give you the maximum range at 18-20 mph.

Excellent! I've always wanted to pull that test. So let me guess, after you shutdown the car and put gas in the tank ... letting it rest for ~5-10 minutes, it started right up. There would have been warning lights and codes but after the battery put on a charge, after three 'reboots', you were good to go?

Bob Wilson

 

So now that you know it can go a mile or two on the traction battery, are you more likely not to let it run out of gas in some god-forsaken place? I don't see how that test helped you.

 

To all people running out of gas: this fact is recorded on the prius computer(s) and will be used against you if your battery dies within the warranty period.

 

"If you shut off your car with a green battery, it should be green when you return."

RWHOYLE said this in a post. I'm not sure that's accurate. I have an '08 with 2000 miles, and drove an '08 loaner for over a week, and it was always the case that, for those infrequent occasions when the car was parked with a nearly full and green battery indicator, upon returning hours later or the next day, the indicator would be in the blue. Seems unlikely that both new cars would have the identical problem, and my car seems to be working fine. I get 51 to 55 mpg so far in 60 to 70 degree temps, lower when cooler.

 

All Batteries self-discharge.

Also, because the prius hates to have the soc in the green levels, it'll always try to use more power to get it to the blue, which increases your chances of residing in the "blue bar" range, that overlaps the green range.

 

Can somebody tell me if the 12V battery in the 08 Prius is maintenance-free (ie. gel-type)? Can't find anything in the manual about that.

 

It's maintenance free, meaning you don't have to add water to it. But it does die after ahwile...

 

It's a sealed Pb-acid battery with liquid electrolyte and vent through a hose to the outside. The only maintenance is replacing it when it dies after 4+ years. YMMV