Replacement of 12 volt auxiliary battery

You have obviously never removed the 12 vdc battery in a 2004-2009 Prius. Took me around 25 minutes



I outlined the battery vent tube for a different post

So, to remove the 12 vdc battery. Disconnect various sense wires, negative cable from unitbody. Remove brake backup module. Get Traction Battery duct out of the way. Finally remove hold-down bracket for battery, wrench battery out.

Reassemble in reverse order. Impossible to do in 5 minutes

 

Replaced mine yesterday with the elearn Optima and kit. Took about 30 minutes. I was surprised to learn that the optima weighs less than the OEM battery by about 1.5 lbs.

 

I bought an optima battery today from Bernie at elearnaid.com and put it in with his help, not easy, not hard...and it works GREAT!! Thanks Bernie.
Art

 

I just did mine tonight with the elearnaid clamp kit. Took about 45 minutes -- I made the mistake of starting too close to dusk, and it was hard to keep my trunk brightly lit. Not to mention that I had to fetch a screw I dropped *after* I bolted down the new batt :Cry:.

Instead of using another 12V battery for "keepalive lifeboat" purposes, I used a Battery Tender. Worked great!

 

Way to go bsd, i see you're in the sf area...lived in the marina for 24 years, a block from the palace of fine arts, nice.
so far the battery is perfect, and now I'm planning on painting part of my black '04; a 2 tone effect, using a deep rolls royce purple, still looking for the right color.
art

 

Is there a thread that shows, with pictures, a step by step replacement of the prius 12 volt battery...??? 2005 with smart key... thanks

Pulled the battery in about 10 minutes... The only real problem was reaching for the bolt that holds the vent in behind the battery... Not a real issue when your taking it out but to re-install you do not want to drop it and have to pull the battery out again...

 

Will the S46B24R work in a 2003 Prius?

 

Just had our second 12V battery failure (and jump start) of the week (it is 3 years old, has been drained once), and decided it was time to replace it, although the dealer said it was OK (even though the printout showed the state of health was low, and the state of charge was 75%). So the dealer did it without using a 12V source to maintain our settings (blew my mind). I've reset everything I could, but wonder if any of the engine or computer functions need to be reset as well, and if the repair was irresponsible, or just SOP? He also claimed the new one comes fully charged: can anyone confirm this?

 

Once you remove standby power, items like short term fuel trim maps are lost. Normal driving should quickly restore those baseline settings

Matter of fact, after a tuneup service like changing the spark plugs, and cleaning the MAF and TB, it's generally a good idea to disconnect the battery to erase the short term maps, and force the computer to learn again

A lead acid battery, like the 12 vdc battery in a Prius or any other vehicle, will lose charge and sulfate just sitting around. Every replacement 12 vdc battery I have ever purchased, was generally at 50% charge.

Or less

It's always a good idea to use a good automatic battery charger to fully charge a battery, before you install it. In conventional vehicles, you put a lot of stress on the $400 alternator forcing it to charge a "new" battery

With a Prius, it can take a LONG time to charge the 12 vdc battery. Eg it would have to be in Ready for at least 2-4 hours.

 

Thanks, we'll try to get it charged up with some driving (and stop worrying about lost settings). I did notice that the 12 vdc battery open circuit voltage seemed higher after I drove home from the shop. I've a dark suspicion that even a new Prius comes with a partially charged battery, and that a regime of short daily trips (our pattern) creates a battery that was never fully charged, never gets fully charged, and is destined for an early demise.

 

Well, the PDI instructions do state that the dealership is supposed to FULLY charge the 12 vdc battery before delivery to the customer

You want to take a bet on how often THAT happens?

 

I successfully replaced my 12v battery

I have Prius 2003 purchased in October 2002.
I have 140000 miles on the car.

It has been reliable over the 7 years that I've owned it.
I'm very happy with this car. I hope to drive it to 200,000 miles.
Recently my car has been slow to start and quick to drain the auxilliary battery this winter. I have had to jump the car to get it started numerous times.

I first tried to buy a battery at wal-mart, then Autozone and my battery didn't even
show up in their books. They suggested I go to Toyota. No way, I knew they would gouge me as they have done in the past.

Autozone told me that the old battery is Japanese and has different size connectors.

Thanks to this site, and others, I decided to install the Optima D51R (reverse posts) purchased
from eLearnaid.com myself. I also bought the installation kit. Total cost was about $163.00 and it took about a week to be shipped to my door.

Last night I installed it. It took about 90 minutes. It was after dark and snowing so that made it more difficult, but I really needed the battery installed.

Here are the issues I had. Loosening the bolts in the tight space were the hardest parts of this. The tools I have didn't fit well into the small space for the battery - behind the left wheel.
* I highly recommend the connection kit from eLearnaid. It has the instructions and everything you need. Read the instructions first. They are verbose and overkill, but it's good to scan it.

I had trouble loosening the Red/positive side battery connector (fusebox). This is easy to unplug and remove from the car so I suggest you unplug it and work with it outside. There are two plugs that hold on this fuse box.

I had to put this into a vise to loosen the bolt that removes the old connector to add the new - bigger connector I received in the kit.
The kit suggest you bend the ridge that the battery sits next to behind the wheel. This can act as a knife during a high speed collision and cut the battery. This is difficult to bend because there is not much room to push the pliers in the small space. I just did what I could.

I also made the mistake of inserting the tube last - this made for a very tight fit trying to connect that last piece once the battery was all locked down.

All in all, it works and I'm glad I did it. I don't know what Toyota charges, but I'm sure it's at least $250 if not $300+.
Also, be sure your battery is secured tight. It has been stated that vibrations can severely limit the life of your battery.
verifyhistory.com

 

Re: I successfully replaced my 12v battery

One of the advantages of the Optima Yellow Top is that the spiral plates handle vibration better than the flat plates of other batteries.

Jeffd

 

Re: I successfully replaced my 12v battery

Congratulations.

I recently bought a battery for my 2004 from my local Toyota dealer and paid ~$135 plus tax.

For the Classic, your Toyota dealer would want to sell you a replacement Panasonic battery which is larger than the original, plus the battery conversion kit. My guess is that the price would be around $135 for the battery plus $40-50 for the conversion kit which includes a new battery bracket, connectors and cabling.

Although some posters have quoted higher prices, usually that includes dealer install labor of 1/2 - 1 hour. The relevant price is what you would pay at the dealer's parts counter, if you wish to compare with eLearnaid or similar alternatives.

 

I had battery issues in Seattle on my '05 Package 6 (left the lights on a few times, and had a few long trips) and got a new battery last year from the dealer. Had to put the car in storage for 5 months (until last month), so came back to a dead aux battery. After a week of driving it alot, it seemed OK, but as soon as I left it off for two nights (in cold WI), it was dead again.

Decided to get the Optima battery from elearnaid, did the replacement, and now it's doing the same thing. The car can't sit for 36 hours without dieing, with a brand new Optima in it (replaced it a week ago).

I did drive around for an hour or two every day after the replacement for a few days, and everything seemed fine.

Digging through the forums, I haven't seen many people have issues once they did the replacement. I'm putting a call into a local dealership (don't know which of the two in Madison is better), but does anyone else have an idea of why a brand new battery that is designed to deep cycle is dieing so quickly?

Thanks,

 

Sorry I don't have an answer to your question about your battery. Wondered if I could please ask you about your car in the past 140000 miles if you have had any other maintenance issues? Just bought my first prius and still contemplating extended warranty. Thank you !

 

Here's my idea: Did you fully charge the Optima battery before you installed it?

If no, then the problem likely is that the battery, when shipped to you, was not charged. If you only drive around for 1-2 hours a day, that is not sufficient to charge the battery.

I suggest that you use a battery charger set to the 2A position, to charge up the battery. Then, during periods of light or no use, plan to use the charger 2x per month, or else buy a battery tender and attach that to the battery at all times when the car is not in use.

 

Unfortunately, I did not think to check that, or think to measure the voltage before the replacement. Also unfortunately, I'm out of country now, and I don't expect my wife to buy and hook up the battery charger and extension cord (no power in my garage). I'm getting her an appointment to bring it to a dealer, and if a slow charge from them will fix it, then great. If not, I'll ask them to look for parasitic loads when the car is off. For the first day it died with the Optima, we went grocery shopping, and left the car running while we were away from it (locking the doors via an open window, then using the auto to roll the window up )

can anyone think of something I should mention to the service writer that would help them? I don't know the quality of this shop yet, so I can't yet assume that they are smart or stupid.

 

Since you are not around, let me suggest something that your wife could do: Make the Prius READY, leave it in P with the parking brake on, and just leave it alone for 12 hours or so (make sure it has enough fuel so that the engine can run when it wants to.)

No need to drive the car during this period. Leave the garage door slightly open so that CO gases can vent to the outside, but not so open so that someone can sneak in and steal the car.

The point of this is to give the 12V battery 12 hours to charge up. Then you don't have to worry about the dealer personnel screwing the car up.

If that doesn't help, then she may have to ask for dealer assistance.

 

I too ordered the Optima, delivered earlier this week. I remember Hobbit describing in his installation writeup that he had checked his upon delivery and found it to be a healthy 12.6V. Mine was at 12.1V. One difference: His came from Elearnaid, whereas they were out of stock when I tried to order mine and suggested Amazon. I ordered from Amazon and I'm guessing they didn't take the time to top off the charge before shipping. Engunneer, given the similar timing, did you order yours from Amazon too?

Meanwhile, to whomever is familiar with BatteryMinder Plus: Any guess as to how long it would take for it to get the Optima up to full charge? I currently have the BatteryMinder at my fiancee's house keeping our motorcycle battery and her lawn tractor batteries charged. As part of planning for the Optima installation, I need to know how long to expect either to leave the battery at her house or to temporarily retrieve the BatteryMinder.