12V Battery Replacement-- A Preemptive Strike

This may be/probably is redundant ? but these are the "step by step" instructions that I did when I recently replaced my 12V battery in my 2005 Prius.

I bought the Optima Yellow top battery (with the adaptor kit)?. The "adaptors" are kind of "hidden" in the slots on the sides of the new battery.
1) Make sure your "power" button is off
2) Attach another 12v car battery by using jumper cables to the jumper battery and then to the jumper connectors in the fuse panel under the hood.
3) Then you need to "get at" your existing battery - you need to first remove the rear deck so the spare is exposed - then remove the battery panel on the very rear RH side.
4) You will see your battery on the "outside" and a fairly large "black box" sitting just to the left of the battery. Remove the bolts that hold the black box brackets to the frame of the car, not at the black box. The black box can than be swung out of the way.
5) There is a dark red plastic "cover" over the + terminal of the battery - it is held in place by 2 press-in clips on the sides - remove that.
6) Carefully remove the battery ground (-) strap from the car frame - again,- keep in mind that there is 12v on the system - so try not to touch your wrenches, etc. to the frame.
7) Remove the (+) battery cable from the battery - same warning as above.
8) There is a black battery hold down strap that has to be removed - one bolt on the left of the battery - other on the RH side - the one on the RH side won't fall down - just remove the nut on the top. Then swing the hold down strap out of the way.
9) There is a black plastic air duct that needs to be removed in order to get the battery up and out of there - just 2 bolts -one at the front of it and one on the outer side at the back of it.
10) You should then be able to lift the old battery up and out with the battery strap.
11) If you DID get the "older" style Yellow top, you will have to add the adaptors to your set-up - the main one is for the (+) battery terminal - put it on the cable first (bolt up from the btm) NOT onto the battery post - as it only goes on the post one correct way.
12) Make sure you get all the little pieces out of the sides of the new battery - there is a vent adaptor in there also.
13) Then drop the new battery in the hole - make sure it sits all the way in - mine wanted to "rock" a little to start with.
14) Then put the black plastic duct back on
15) Attach the ground cable, the positive cable, battery hold down, etc. and pull off the existing vent fitting and replace with the one in the battery kit.
16) Then just reverse the dis-assembly process.
17) Unhook the battery up front and you s/b A-OK.

 

Excellent check list. My only technique additions to it:

http://www.cardomain.com/ride/3963817/2008-toyota-prius-touring-hatchback-4d/page-9

• magnetic tools to aid in the battery duct-work bolt handling

• portable jump starter versus stand alone 12 volt battery for volatile memory settings (see photos at link)
• management of rubber battery carry-handle to allow floor trim to be re-installed correctly (see photos at link)

Thanks


Cheers


Mike

 

...recently folks were saying to measure voltage on arrival
I have not checked yet and it was 6 months ago hope OK

 

I used my Scangauge II volts reading, after installation and without the engine running (and interior lights had been on prior to test, showed 12.6 volts......).

I should check again, now that I've had it installed for 8 days.....

Thanks

Cheers

Mike

 

Did another voltage check yesterday, 11.6V static dropping to 11.1V under load. The ICE is spending a lot of time trying to charge the battery too, with mpg dropping to 44. Ordered the Optima Batteries DS46B24R YellowTop Prius Auxiliary today. Should be here in a week. And that takes care of that.

 

Aussie experience. My Gen III battery has died because of stupidity. (mine) I ordered an optima and paid for it only for the supplier to ring back and tell me that the Singapore distribution centre had sent the incorrect batteries and it would be at least 4 weeks for the right ones to arrive. They graciously returned my money and am having our local dealer fit a new toyota battery tomorrow.

Sigh... I was so looking forward to the Optima experiment. :-((

 

Bad luck about the Optimo Feri.

BTW.. How much is the dealer charging for the battery installed?

 

Battery arrived yesterday. Took about an hour to install. I wanted to share some installation tips I made use of which may help others. As noted in previous posts, there is a difficulty removing/replacing the screw that supports the body-side traction battery ventilation housing. Using a magnetic holder might work. I used an extra long bread tie that I folded into the 10mm socket and then pressed it over the screw head. That worked quite well for reinstalling. Also read in a post that the battery vent line presents some problems. I noted that the right-angle plastic fitting that inserts into the battery is keyed on one side and the length of hose isn't quite long enough to reach. If you observe the proper keying, the fitting will snap into the battery top quite securely. On my car there was about a half an inch of extra hose extending down from the grommet that goes through the trunk floor. I pulled the grommet down flush with the end of the hose and relieved stress on the hose quite nicely. I'm looking forward to better fuel mileage now.

 

I am probably going to need to replace my 12v battery. What's the advantage of using the Optima over the OEM battery? Any advice on where to buy it?

 

It may last longer, especially after you drain it leaving the lights on overnight can ruin a battery. It is also more expensive to buy and takes longer to get.

 

I'm sure folks very familiar with battery technology will step in to correct me, but I think the simple answer is that the Optima battery is a type that is a deep cycle battery but shaped to fit into the Prius.

Again, my bare bones understanding of a deep cycle battery is that it is designed to be run down (compared to a normal 12 volt battery) much farther without damaging it.

 

I believe I will be doing this procedure on my 2005 Prius sometime this week, and would really appreciate if someone could point me to a photo
or else a good description of the "jumper connectors in the fuse panel".

When I changed the battery in my 2003 Prius a few years ago, I did everything at the back of the car, since I was not sure where else to hook up.
Thank you very much!

 

Here are some shots of the part to attached your "+" jumper cable (inside the fuse box under the hood on the drivers (port) side), followed by a single shot of the recommended body point to attach your "-" cable (suspension bolt, strut tower, passenger (starboard) side.
Cheers
Mike

 

Can I use my other car's battery as my 12v power supply while changing the Prius battery? I was thinking of using my regular jumper cables and running the negative jumper cable from the other car to a ground point then For the positive, I could use the cable with a smaller jumper attached from the end of the big jumper cables to the positive post in the fuse box. Or if I can find a long enough wire in my toolbox, just running a small jumper from the battery to the prius fuse box (maybe with a fuse if I get fancy). Would that work?

Thanks!
Aaron

 

Yes. If you consult your owners manual, this technique is described in detail.
NEVER let the other vehicle touch the Prius. Connect good battery "+" to the "+" I showed you in the photo. Then connect good battery "-" to a suitable ground point on your Prius. The suggested suitable ground point in your Prius, as found in your owners manual, will be one of the passenger side front strut bolts.

Always go positive good to positive bad first, then negative good to chassis bad. If your cords are too short, how about a portable battery jumper (if available)? If you must "patch-cord", be REALLY careful and wrap all bare ends in electrical tape or you will inevitably fry something.....

 

tv4fish, THANK YOU for posting these clear instructions. It made the installation do-able.

 

There are two Optima batteries that fit but only one that has the original (pencil size) Prius terminals. Make sure to get
OPTIMA® Batteries 8171-767 DS46B24R YELLOWTOP® Prius® Auxiliary Battery

There are several sellers on Amazon or you can get one from the nice folks at E-learnaid. (About $171 as of November 2013)(Local dealers were anywhere from $199 to $242)

I have used some optima batteries due to the ability to sit at any angle and that they do not vent or leak anything. The have more power in general as well. I had some trouble with the original design many years ago but not since they redesigned. I have one that has been working for about 15 years.

It took me about 20 minutes to replace it after watching some YouTube videos. The battery has a place to hold the vent hose but mine didn't reach. The 90 degree fitting on the original battery wouldn't come out, maybe yours will twist-pull out. I just put a golf tee in the hose to keep bugs out .

BTW, my Prius is an 08 with about 49K miles.

One night I turned the car on and one of the HID headlights didn't come on for a couple seconds. This was the first cold night of the season. The next evening, the next time I drove the car, the Smartkey would not open the door and when I opened it with the hard key, it would not power on. I played with the emergency brake and opening and closing a door and somehow managed to get the computer up long enough to start the engine. I used the built-in scan tool to test the voltage (see YouTube) after I got back home from an errand and watched it drop from 12 to about 9.5 volts before I turned accessory mode off. I pressed the button under the steering wheel to turn the Smartkey service off. Nevertheless, the next morning it would not power on at all. The key indicator light was flashing and it was making a buzzing noise when it flashed. I had to pay more to get the battery locally ($199) since I couldn't wait to have one shipped.

PS. Once the Prius is powered on, the 12V battery charges whether the gasoline engine is running or not. Since the 12V batter does not actually run a starter, I do not feel that short trips drain the battery as others claim. However, infrequent usage of a car with the Smartkey system will drain the battery a lot and wear it out faster. The Optima is a deep cycle battery so it should be more tolerant of this.

 

What dealers in Canada are there?

Is this place legit?

8171-767 DS46B24R - OPTIMA Battery

 

Jah, the Optima may be able to supply more cranking amps than the OEM battery "something that is totally irrelevant for the Prius" but in actual fact has less AH capacity than the OEM battery. Being 38 AH against 40 AH for the OEM, it's only advantage is it's recovery from a deep discharge they actually hold less "power".

John (Britprius)

 

I have extracted the quote above from a post I put in the Technical Discussion thread a week ago. Thought I would revive an applicable 12V battery thread to discuss the situation further.

So it seems that the Optima battery might need a periodic jolt from a battery charger in order to maintain a "healthy" level of capacity. I am left to assume this based on my experience above and more recent measurements. There are other posts in similar battery threads that say about the same. I think the consensus recommendation is a monthly topping-up on a battery charger.

I have an automatic battery charger (Schumacher Model SE-5212A) which can provide a 2 amp or 10 amp charging cycle. After making the above measurements a week ago, I removed the battery from the car in preparation to have it load tested by AutoZone. I put it on the charger at the 10 amp setting until a steady fully charged indication was achieved. That took about 2 hours. Then I took it over to AutoZone where it checked out fine. I then put the battery back into service. It's now a week later, and after letting the car sit unused for 3 days I hooked up my DVOM to the jump connectors in the front engine compartment fuse panel. The first measurement was at 12.17V. I then placed the DVOM against the raised hood so I could see the display and ran through the MFD 12V test sequence. I determined that my MFD voltage measurements agree almost directly with my DVOM. No offset required. I also saw the voltage drop into the 11.7-11-9V range at the second press of the Power button, which the test says is an indication of a marginal battery (when the voltage drops below 12.0V). Then with brake pedal press and Power button again the voltage rose to 13.8V, where it is supposed to be.

I am a little less worried that my battery was maybe failing, but I'm still concerned that something still might be amiss. I really don't have enough data to nail it down though. And it is strange that this battery somehow benefits from periodic charging even though my use cycle (700 highway miles driven per week) should provide more than enough charging. I will just have to continue monitoring the situation and see if anything changes.