2008 Prius Touring Aux Battery needing replacement

Welcome!

I'd venture that half the Gen II owners registered here have replaced the 12V, either proactively, or due to failure like yours. It is the #1 source of problems.

Typical dealership replacement starts at $225, so $327 is a little steep.

 

I replaced mine on my 06 in Feb 2011 w/an Optima Yellow Top. You could've DIY for cheaper...

Out of curiosity, what dealer did you buy your Prius from? Only reason why I ask is because I hope it wasn't Roseville Toyota or another dealer following such poor practices (http://priuschat.com/forums/gen-ii-prius-technical-discussion/100011-closed-minds.html). Running the factory 12 volt until it's totally drained is bad for it.

 

You guys with cars years younger than mine replacing your 12V batteries is starting to worry me. I'm still on the original with my 2006 (68k miles).

I've been thinking that I should top off the battery with some distilled water. Anybody else gotten the thing apart enough to do that?

 

If your original battery has the traditional wet cell construction then that would be fine. However if your original battery is AGM that would be a good way to kill it for sure.

After the battery is removed from the car you can shake it to see if you hear fluid, or shine a light through the translucent white case and tilt it to see if you can find the fluid level in the battery. Those would be a couple of ways to identify whether it has wet cells or not.

It is easy enough to use a single-edge razor blade to peel off the top label (which contains a printed warning not to remove it) which exposes the rectangular translucent plastic cover over the six cells. Then you can remove the cover and look in to see whether your battery is AGM or not. If you see fuzzy white mats separating the lead plates, the battery is AGM.

 

These are sealed batteries. No place to top them off. I replaced the OEM batteries in both my 06 & 07 in September. It was not hard at all and took about 20 minutes per vehicle. I used the Optima yellow top from elearnaid.com. It comes with fairly easy to follow instructions. $360 for two batteries with kit. The terminal posts are larger in diameter than the stock Toyota battery. The kit contains the connectors for these posts. Follow the directions & you will be fine.

 

Just did this to my '07 w/ 115k. As Patrick said, take it out, peel off the label, take out the clear strip covering the caps and then pop off each little rubber cap. Unfortunatley on mine, the battery is Not clear but a black case, ie. can't see through it to get an accurate level indication. On mine, three of the six cells were below the top of the inner plates as far as fluid level. Added distilled water to bring all 6 cells up, reassemble and back in business. Was done about a month ago, no issues.

Just be careful not to lose the little rubber caps and pay attention to fluid level if you don't have the exterior markers on the case. Do Not fill up to the top w/ water.

Oh ya, cost = 0 (Already had the distilled water).

 

Replaced the aux battery in my wife's 2007 Prius last year - dealer - battery was ~$130 I think - labor $45 - (had the battery exposed - must have taken them all of 5 minutes) and misc changes of $22 = total about $200. Could have easily swapped the battery out my self. Original lasted about 3.5 years - not sure how long it was on the lot.

 

I'm still on my original (also a 06) with 190,000kms (118,060 miles).
I think I'll replace it next spring if it makes it through the winter.
So far, nothing has been done to the car other then oil changes, transmission fluid changes and an alignment and tires.

 

I just replaced mine last week, at just under 80,000. The check engine light came on, and the dealer said that was the problem at $320. 40 miles later, the CEL comes back on.

I didn't believe it was the battery in the first place. I had one issue with it starting in the dead of winter last year, but after the boost I haven't had a problem. CEL never came on then.

Anyone else experience a CEL with aux battery problems?

 

It is most often the underlying cause of ABS/VSC/TRAC lights.

 

I have a 2006 Toyota prius which needs auxiliary battery replacement. It was working fine until one day it all freaked out and would not start, dashboard lighted up. After jump starting it has been working fine but dealer said it needs new battery.

How easy is it to replace the battery in trunk? Can you buy this battery and do it yourself?

 

Optima BatteriesOptima Batteries DS46B24R YellowTop Prius Auxiliary Battery

If your car is not smart key, then the flange on the battery bracket will cause this to not fit right, and you will need to cut it off. Otherwise it is not too bad a job whether this new Optima battery or one from the dealer, instructions are here.

 

Whenever a dealer says "battery", check it yourself before spending money:
http://priuschat.com/forums/newbie-forum/73400-weird-stuff-happening-mpgs-dropping-test-battery.html

If it is bad it ought to cost around $200 for dealer replacement, not $320.

 

Just replaced my aux battery with a werker agm sealed battery model wka12-55c/fr
From batteries plus $126 plus tax The 33 amp modl was same price. It was. Tight fit but went in no problem . Battery has threaded fittings and comes with about a 1/4 inch bolt.


Removed prius battery positive clamp and bolted the black fusible link box right to the positive terminal with a small washer underneath to bridge the space in the bracket. Bought. Ground strap for the negative side that had two bolt fittings instead of the prius clamp. Did not want to modify any of the prius hardware. Case i want to revert back to stock battery.

Hope it lasts 5 or 6 years.

 

I have an '06 and I replaced my 12v with a dealer purchased Toyota battery - cost $138 and by using a booster battery hooked up under the hood, I switched out the battery in about a half hour and didn't loose any radio settings etc.

Very easy. I was surprised the dealer battery was so reasonably priced. I paid about $115 ( at Batteries Plus) for the 12v in my Miata - same sort of rear mounted vented battery.

 

tbradway, thanks for posting this. There has been much discussion lately since Britprius (John) started researching this alternative for the Prius. The problem we have run into in the states is finding specific mobility battery alternatives, which seem to much more resilient than the OEM and typical replacements, is the needed venting that allows a tube to direct possible gases out of the vehicle. Does your selection have accept the Prius tube or allow for the installation of a replacement?