A Novice¯s Experience Replacing The Prius 12volt Battery - Toyota Prius Forum : Prius Online Toyota Forums
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post #1 of 9 (permalink) Old 01-14-2009, 04:22 PM Thread Starter
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Default A Novice’s Experience Replacing The Prius 12volt Battery

Recently my ’04 Prius began to experience some perplexing problems which all seemed to revolve around power issues and always involved turning off or starting the car. I would turn it off and be unable to lock the doors. I would have to hit the power button multiple times to start, cycling through various error messages and dashboard warnings before getting going. I eventually found that the only way it would start was with a jump from another car. Some internet research and logical deductions led me to the correct assumption that the 12volt battery was going bad.

I called to the nearest Toyota dealer and got a quote of $217.90 for the battery and $94.50 in labor. Figuring I could do better than $314 dollars, I searched the internet where all signs pointed to the Optima battery replacement by eLearnAid. Ignoring my inexperience (my previous car maintenance was limited to replacing wiper blades, headlights and the aforementioned jump starting) I boldly ordered the battery and its “installation kit” for a total of $180.

The battery arrived on a cold January day and I resolved to replace it after work. I was without two recommended tools, a vise (or vise grip) and a socket extender. I borrowed the socket extender but did without the vise. The instructions were good as was the advice from the web, but the job still took me 3 ½ hours in 30 degree weather and left me with a feeling of accomplishment but ultimately feeling like I should have just taken it to the dealer and spared myself the pain.

I’m not going to go over everything because much went perfectly well. There were some sticking points however that I will focus on to hopefully give other novices an idea of the possible problems they might encounter should they attempt to do this replacement.

First stumbling block: Opening the hatchback. Not so simple as it sounds when you have no power at all from the battery. After a few minutes of pondering I eventually found the entry in the Prius manual that describes the procedure. Unfortunately the diagram provided is not clear nor is the language used describe where to find the lever. It is in the exact center of the back wall of the trunk space in a recessed hole. Time lost: 15 min.

Second stumbling block: Removing the bolt holding the positive lead to the fuse assembly. This is where the vise or vise grip was called for… I did the job with a large adjustable pliers and an adjustable wrench. The problem is you need to immobilize the whole assembly without breaking the plastic fuse housing and that is tough without a vise. I eventually got it by persistence and holding the pliers against the floor with my foot while turning the bolt. Time lost: 40 min

Third stumbling block: Screwing down the battery holder over the new battery. One side was easy, the other nearly impossible. The bolt on the side closest to the center of the car was difficult to access because it was in a narrow space about 3 – 4 inches below the top of the battery on one side and some lousy black box on the other. Also, the hole for the bolt was very slightly misaligned so it went in at a slight angle. The combination made it basically impossible to get the socket on the end of the extender to sit down over the head of the bolt and screw it in at the correct angle. I eventually ended up removing the black box in front to improve the angle and was able to catch the threads correctly on about the 100th try. Time lost: 45 min. (on one bolt!)

Final stumbling block: Screwing the large vent tube back onto the car wall. The screw in question is somewhat hard to access and needs to be started by hand and finished with a socket extender. By the time I got to this step I had been out in the cold for 3 hours and as a result I twice managed to drop the screw down into the battery compartment because of my cold fingers. Each time required removing the black plastic vent to allow access to reach in and fumble around for the screw. Time lost: 20 min.

So, to save my $134 dollars I did without normal use of my car for five days while waiting for the battery and then spent 3 ½ frustrating and cold hours on the replacement. On the positive side I gained some experience, a feeling of accomplishment and a better understanding of what a car mechanic’s labor fee is all about… and of course, a working Prius. Not really a fair trade in the end but I’m not sorry I did it. Next time I hope my battery dies in June however.
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post #2 of 9 (permalink) Old 01-15-2009, 01:38 PM
 
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Default Re: A Novice’s Experience Replacing The Prius 12volt Battery

That's great experience. Next time you'll be able to do it much faster, but it will be a while as your new battery is a good one that can handle deep discharges and you will be careful not to drain it often.

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post #3 of 9 (permalink) Old 01-15-2009, 05:41 PM
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Default Re: A Novice’s Experience Replacing The Prius 12volt Battery

Don't feel bad about the difficulty. Mechanics suffer from the same problems you had.

Note for "next time". Instead of looking for or trying to use the inside hatch release, just use jumper cables and connect the new battery to the "boost point" under the hood. Then open the hatch in the normal way.

At any rate, you learned a lot, got a very good battery, and can be proud of your job.

Vehicle:
Pearl is a 2007 Driftwood Pearl Prius
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post #4 of 9 (permalink) Old 01-15-2009, 10:00 PM
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Default Re: A Novice’s Experience Replacing The Prius 12volt Battery

Isn't it too bad that the weakest componant that has been in the Prius for years does not take the fifteen minutes that every other car battery does to change! (Hi tech?)



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post #5 of 9 (permalink) Old 01-16-2009, 10:32 AM
 
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Default Re: A Novice’s Experience Replacing The Prius 12volt Battery

Key learnings:
- When weird stuff starts to happen, check the battery voltage promptly. If it is low replace the battery before it fails entirely.
- Use the recommended tools.

These profusely illustrated ELearnaid Optima installation experiences by EVnut and Hobbit may be helpful:
http://evnut.com/prius_battery_optima.html
http://techno-fandom.org/~hobbit/cars/p ... a/ela.html
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post #6 of 9 (permalink) Old 01-16-2009, 01:13 PM Thread Starter
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Default Re: A Novice’s Experience Replacing The Prius 12volt Battery

I never thought about hooking up the Optima battery to jump the car and open the hatchback. Makes perfect sense though.
I did find both of those web pages helpful, however the fact that both made it look so easy encouraged me to write up my experience in order to give folks an idea of possible problems that could slow you down.
Given the circumstances the #1 thing I would do differently would be to get hold of a vise. That would probably have cut 30 or more min off the job.
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post #7 of 9 (permalink) Old 01-17-2009, 09:52 AM
 
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Default Re: A Novice’s Experience Replacing The Prius 12volt Battery

Yes, thanks very much! Knowing what didn't go smoothly is a big help. I expect to do this job myself soon.
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post #8 of 9 (permalink) Old 12-17-2010, 04:14 PM Thread Starter
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Default Re: A Novice’s Experience Replacing The Prius 12volt Battery

So 23 months later the Optima battery died. Yes it has been cold this December but my impression from everyone was that the Optima battery was better than standard Toyota batteries so I'm bummed that it lasted less than two years. I've got to figure that it wasn't my installation that caused the problem... if that was the case it would have happened quicker than 23 months.

Not a very happy ending but at least this time the car is at the dealer and I won't be freezing my fingers off.
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post #9 of 9 (permalink) Old 12-18-2010, 02:50 PM
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Default Re: A Novice’s Experience Replacing The Prius 12volt Battery

If your car is already at the dealer, this may be too late. The Optima battery has a pretty long warranty; and ELearnAid was accomodating when the "Miata" battery died prematurely in our 2002 Prius and gave us a fair adjustment on a new one. The second installation is always easier, but it may be worth the extra money to let the dealer do it since it is so cold where you are.
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