Replacement of 12 volt auxiliary battery

Hi Parker,

Congratulations for realizing that the battery terminal polarity on the Optima battery is reversed. I assume that the other posters who successfully used that battery installed it so that the terminals are adjacent to the fender. This will be a problem if the RR fender is hit in an accident, shorting the positive terminal to the body.

 

On mine it looked like there was going to be a conflict between the positive terminal and the plastic duct that's routed near the battery. I put the battery in place that way and put the duct back in before hooking up the cables--the duct was touching the positive terminal (I didn't have the big positive cable/fuse thing hooked up yet.) Maybe it could all be jammed together like that with a little bit of flex in the duct; I didn't really try since I expect to be able to return the battery to Costco easily enough.

 

I have a 2004. The utility battery died. I read all the posts here and some of the links. I was running my Prius on a spare battery (strapped down in the trunk) connected to the car via jumper cables for 2 days (dealship was closed). I bought the replacement from the dealer at $138. The iInstructions for replacingposted here in this forum are very well written.
FYI FOR ALL PRIUS OWNERS THE SPARE TIRE, AREA BATTERY COMPARTMENT AND STORAGE COMPARTMENT ON THE OPPOSITE SIDE WERE FULL OF WATER.
Recommend opening and cleaning this area regularly. Mine was all rusty. Toyota still has rusting out (body cancer) to deal with.

 

This being the case, you may want to investigate the cause of this leak. Did the car suffer accident damage to the rear? The rubber seal that lines the hatch opening is the likely culprit for a leak in the hatch area.

 

I agree with Patrick that Daryles has an unusual water situation and it deserves further investigation. And a thread of its own if you find anything out, Daryles.

 

A battery replacement is a straightforward job. get a battery with the posts in the right locations and size of battery correct it is a simple R&R. Not a big deal. Autozone or any other parts place that has the correct battery will work.

 

That is simply NOT TRUE.

We have covered this in other threads.

http://priuschat.com/forums/care-ma...ng/59640-looking-aftermarket-12v-battery.html

The Prius 12 vdc battery has unique post size, and the need to be totally sealed with provision for a vent tube.

The closest to a "simple" replacement is the elearnaid Optima which costs just as much as the dealership battery. This Optima is actually intended for a Mazda Miata, so has the correct vent tube provision

Otherwise, there is no generic replacement for the Prius. Yes, you can jury-rig a battery to work, but it will probably not be safe

 

Ok, just for giggles I went to the NAPA online and entered my vehicle, 2004 Toyota Prius, then clicked on Battery

"No Results Found, Contact Dealer"

However, when I went to Autozone online, they claim to have a Duralast that fits the Prius, for $100. I cannot verify the details of this battery, since the only market for externally vented batteries are Mazda Miata and Toyota Prius, a national parts chain probably wouldn't have such a battery

I do know that here in Canada, Canadian Tire claims to have no such battery for the Prius. Neither does Parts Source or Napa Canada

 

Hello Jayman: You are of course technically correct on all points. However, as with any mechanical/electrical device there are ways to get around anything and save some dollars. We have already seen this numerous times with transmissions, engines and service items. Priuschat members seem to generally support this type of activity. Your hard mindset, dedicated to the Prius battery problem is contrary to this spirit. This reminds me of the dealerships constant warnings about defeating the the warranty if one makes any mod and varies at all from taking the car directly to the dealer for all service and repair. As I mentioned before, I'm using as an Aux bat, one that I happened to have from a Honda. Wet cell, no venting ( except for inherent battery design on caps) I did drill a hole above the cells and installed the vent tube, although it probably was not necessary. The poster that preceded you was quite correct, "One can use any battery" with certain reservations: changing sizing on the post, make sure electrical sizing is compatible, roughly about 30AH Battery. If using a wet cell make sure electrolyte is not overfull and last make sure battery is secure. Since the Honda bat is larger, that is not a problem as it can't go anywhere. I encourage all Prius owners to go ahead and experiment with changing the battery, BUT, keep a back-up handy. Or: a charger. P.S. My battery installation is Safe. You can't go wrong by following Jaymans advice to the letter, it's just not as much fun.:rockon:

 

Hi Andy,

Consider the possibility that your car might be hit hard in the right rear fender in an accident and battery acid may be sprayed around the hatch area. Given that scenario, which IMO has a reasonable chance to happen at some point during the vehicle's life, I would question your assertion that use of a traditional wet cell battery is safe.

Its certainly your right to assess the cost/benefit relationship of using an AGM battery vs. a regular battery, and make the choice that suits you. I'd just like to make sure that other members considering this have full info needed to make the decision.

 

The last thing Id worry about would be the battery.

 

I again must bow down to your excellent logic PAT, as the above poster said: " In a accident, the battery is the last thing I would worry about" I had a VW bug for 10 years 1966 1300, battery under back seat, a WET cell. Never had any problem with accidents. Biggest problem was remembering not to overfill the water addition to cells. No additional ventilation to preclude a hydrogen explosion. Actually no ventilation at all! I agree that in a bad rear end collision, if the battery ejected and if the trunk floorboard also displaced itself there is a remote possibility of a tragic set of cicumstances. I think it would be a very rare occurance.

 

Ummm...not to be contrary, But the VW battery had a vent tube similar to the one on the Prius battery, and for the same reason; gas venting into the passenger compartment. Additionally, many models had a mechanical voltage regulator under the same seat. You know, the kind with points? Hydrogen gas and a voltage regulator with points; not a combination you want three feet behind your seat. If you need more reason, those fumes cause corrosion. That's why you used to see so many old Beetles with holes in the floor where the battery used to be.

Has anyone here actually used the elearnaid battery kit? My '05 just turned 130k and it's about time to replace the 12v battery...

Thanks,


Chuck

 

Actually there are many posts on the forum of folks replacing the OEM battery with the Optima from elearnaid. If you want detailed photos, our resident mad scientist, hobbit, has the entire install at his web site

Prius 12V swap

The positive clamp appears to give the most trouble

 

Yep, and it went well. You will need every tool listed in the instructions, and if you don't have a bench vise, a lot of hand strength to take apart the original positive clamp assembly.

The lug on the new negative cable which attaches that cable to the stud on the car's inside wall may need to be bent slightly so that it does not tend to pull the stud out of the wall as the mounting nut is tightened.

 

It's a good opportunity to put those hairy mitts to work

 

Dude - just go to Toyota and buy a replacement battery that they sell. Guaranteed to fit, will last 4 to 5 years, etc.

check out Burnsville Toyota of Burnsville MN. Great customer service. About the best price of any internet connected Toyota Dealer.

Stay away from changing any of your car's clamps, wires, etc. One wrench and you can change out the exising battery in 5 minutes.

 

... also 'dude' ( ) The optima is equally great if you simply need a more powerful battery. Remember, it was designed to have cranking amps. Reliance on Toyota's tiny powered (but stronger in price) aux battery won't get you squat, if you're one of those who like to sit in your car with the stereo blasting, programing phone book data bases, etc. Your near new Toyota OEM will be dead in record time, begging for a recharge. THAT's why you don't just go out and clunk down more dough, for less product. Heck I wish I'd have changed mine out sooner, just for the extra oomph! btw, isn't this about the 100 millionth time this battery topic zombie has been resurrected?

 

And one can always take the Optima and the installation kit to a shop and pay them to install it. A little more money gets you what should be a significantly better battery.