2005 Prius 241,000 Miles Hybrid Battery Replacement Story

Hi Guys,

Sharing my battery replacement story to help fellow priuschatters in the future.

Couple of weeks ago I noticed that my battery charge on the hud was fluctuating between full and low too quickly. I was seeing full charge on the battery sometimes which I have only seen once in my life before (after a 5 minute long downhill drive near the Grand Canyon). The indications quickly told me that something was wrong. And figuring out the symptoms and the miles on my car (241 k) I fully suspected that it was the battery. Still I kept driving the car for the next three days as there were no warning lights on and it was driving fine. The acceleration was not up to the mark and the engine was taking over whenever the battery cannot supply enough power. Although there wasn’t much difference in MPG there was only a drop of couple of MPGs compared to the regular that I was getting. Then I believe on the third day the Prius dash lit up like a Christmas tree. The Master Warning light, check engine light and VSC were on. The BRAKE light was not on so that meant that I can still drive the Prius home and to the dealership. At that point I thought enough is enough and I called the dealership and booked and appointment couple of days later.

The Dealership:
After diagnosis the dealership told me that it was in fact the HV battery. The new battery will cost around $2600 and $350 in labor. However these batteries are on back order and I will have to wait around 4 weeks for the battery to arrive. I also had the option of expediting the order for which I would have to pay $600 more (based on the percentage on the part ordered). In an expedited order the battery will arrive in a week and I will also get a loaner car from the dealership to drive around. The battery and labor will come with a 1 year replacement warranty with unlimited miles. I asked them what will happen to the old core on my car? They told me it will go back to Toyota for rebuilding. If I want to keep the core I will have to pay $1350 for it.
Now my car on KBB is worth around $6000 and it made no sense for me to spend $3000 on it. I had done some research previously and saw HV Batteries on Prius go from around $600 to $1,000 with 90 day warranty. Also I would not have to wait for 4 weeks as they can deliver the battery within 4 to 8 days. So I asked the dealership if they would put a salvaged battery which I can order online in the car. I can pay labor and I do not expect any warranty on the job. The dealership refused to put a salvaged part on my car so I paid the $98 diagnosis fee came back home and started the search for someone who will do it.

The Independent Shop:
It has been my and most people perception that working on hybrids need specialized skill and training it is difficult to find anyone to do the job. I started my search online and found no shops in Houston that claimed on their webpages that they work on Hybrids. After talking to a company that converts normal cars to electric car I got contact for a shop that they have worked with on hybrids. I called up the shop and they quoted me $400 total in labor $250 to replace the battery and $150 to program the battery computer. The shop people didn’t sound too knowledgeable and I thought the labor on programming the battery computer was a complete bullshit. I thought if this shop is ready to do the job maybe my regular mechanic might do it too. I have never asked if he works on hybrids but there is no harm giving him a call. So I called him and he said that he has done it before around 5 or 6 times on a Prius told me $350 in labor also told me that there is no reprogramming of the battery computer required. The battery computer comes with the new battery or they can use the one from the old one if it doesn’t.
I asked him what will he do with the old core? He said I can have it if I want, he has 3 of them lying around and no one wants them.?? Anyone has any idea what can be done with the old core?
He said that I can purchase the battery via an online retailer and get it delivered to him. However he will not be able to give his usual 12 months warranty on parts and labor as the battery is not new.
I was happy that my regular mechanic who I have trusted many times before was able to work on my car and now I started my search for a battery.

Buying the HV battery online:
Reinvolt was an option their battery will cost me around $1600 and will save me grand but since I was seeing batteries go from $600 to $1,000 on ebay I was looking to save a lot more. I saw a battery from a 2009 Prius online with 1k miles posted by LKQ Georgia on eBay. It came with 90 day warranty. I did some research on LKQ came to know that they are one of the largest recyclers for salvaged auto parts. On their website they were offering up to a 1 year warranty on many of their parts. I wanted to know if they can offer me the same warranty on this battery that they have listed on ebay or not. I called LKQ Online and they asked me to call LKQ Georgia, problem was it was 4:00 PM in Houston on a Friday and LKQ Georgia was already closed (different timezone). So I decided to call LKQ Texas and see if they had a battery in Houston. LKQ Texas offered me a battery in Houston which had 40,000 miles on it for $850 and $15 extra for a 1 year warranty. They will also deliver the battery to my mechanic shop the next business day. They also told me that my mechanic’s shop was in their system and it would be better if he can directly order the battery from them. That way the battery will also come with reimbursable labor. Did I hear that right reimbursable labor? I confirmed it again. This was awesome so I don’t have to worry about battery issue for a year. I asked my mechanic to order the battery from LKQ.

After a 3-4 days my mechanic finally got time to put in the battery and I asked him to do some more repairs on the car that were pending. He cut me a little slack on the labor and I paid a total of approx. $1200 dollars for battery + labor and $200 on other stuff such as replacing serpentine belt and working on front brakes etc.

Lesson Learned:

• Your across the street independent shop may work on hybrids. Just ask. My mechanic told me that they have replaced inverters and other stuff too on hybrid.
• Salvage battery is not a bad choice. You might even get parts and labor warranty depending on who you are buying it from. For the price I paid I can replace the battery twice and make sure I can run the car for two more years. Still I will be spending less money. Also there is a waiting line at Toyota and you can get a salvaged one quicker than that.
• Calling people and asking for info helped me more than searching on the internet did.

If I look at the repair price I might have been able to lower it by waiting on battery from eBay but I was in a hurry to repair my car. I think I did well, I hope the battery lasts as long as the original one did. Feel free to comment. If anyone has suggestion what to do with the old core then let me know. Thanks

Good write-up!! Thanks for sharing!

Nice write-up ! Good luck on many more happy miles with your Prius.

Was the replacement battery modules voltages checked and rebalanced ?

The complete battery was replaced not individual modules. (If I am understanding you right)

If (a big If) I understand the lessons battery wizard Seilerts has been teaching us, a traction battery left unused (say, on a shelf after being removed from a totaled car,) discharges in a non-uniform manner across its modules.

While you may be able to plop it in to another car and drive happily off, you have a higher risk of earlier or premature failure because of the above problem. I gather that any battery that has sat more than (6 ?) months should be reconditioned. Part of what you pay the good folks at re-involt (and Seilerts, for that matter) is for this service.

I imagine that it might be worth keeping the old battery in case the replacement fails. Could a shop identify which modules in a each battery are good and which are bad and then put all the best modules into one battery? If your shop has several bad batteries lying around they probably haven't thought of this or decided that it's not worth it.

Before the battery was put in my car it was with the Mechanic for 3-4 days. He did tell me that he checked the battery and voltages and it looked in good working condition. I am not sure if re-balancing was a part of it or if he was checking for variation in voltages across cells.

This is what I would have done if my battery didn't had 241 k miles on it. With that many miles sooner or later all modules on the battery will fail. Also my mechanic told me that they have always replaced the whole battery never individual modules. They probably don't wanna mess with it I think.

I think you did BETTER than that - I think you did GREAT. Good job on checking things out yourself!

Going into the HV battery and balancing the modules requires a number of recharger/rebalancer units (I and Seilerts use Supermate DC6s - I have one and he has 14 which allows him to balance half the modules in parallel in two days) each costs about $35. It also requires one to climb a learning curve on how to set up the balancing units and the expertise to open the battery and operate safely. Doing a rebalancing of a salvaged battery not only confirms its fitness for use, it gets it back to a balanced state which means that it will last longer in use.

My HV battery failed at 195k miles and 27 of the 28 modules were fit for reuse after rebalancing, so don't throw out you old battery.

JeffD

Good to know this. Well I can get my battery from the mechanic, but I do not want to store it with me. I don't know anyone in Houston who will take this battery from me and re-balance and reuse it (otherwise I would have asked them to work on my Prius when my battery failed).
What are my options? What do you think?

So if one find an HV salvage battery it can be balanced for $35 plus shipping I assume?

The harware to do module rebalancing costs $35. You do have to pay for the labor/expertise since it takes about 1.5 days for one rebalncer unit to rebalance one module (and there are 28 of them. Replacing a module can be done in about a half hour given that the battery is open and on a work bench.

There is a reason that a ReInVolt battery costs a bit more than $1600.

If I had to fix mine again, I would buy some more rebalancing units, a recent vintage salvaged battery (modules from 2010 on are a bit better than 2004-2009 modules) and a couple spare modules so that I could get that battery refurbished while limping around using my existing battery in the interim. Then I would once again rebalance my old modules for resale on eBay as I did this time.

JeffD

Drove the car to work today. I think I am getting better MPG somewhere between 5 to 8 MPG more than what I usually get. There was no wind today so I know it is not that.

Anyway still early to speculate on the MPG increase I will need to run the car for a month to figure out if there is any actual performance improvement.

Good Story. Also the additional Re-balancing Info is very useful.

I thought Toyota wants to reclaim these batteries, even paying a 'bounty' of something like $150 to get them back and into their recycling program. Is this not true?

Toyota recycling = careful waste management and reclaiming a small percentage of materials

Refurbishing a traction battery = reusing 98% of it in a Prius (just one or two replaced Modules)

JeffD

Good effort! I will probably go Reinvolt route when the time comes, although I will check with some Prius shops.

My 2 cents:

If you get a complete battery from a junkyard, DON'T TOUCH A THING. Just put it in and run it. It would have had to have been sitting for a really long time, over a year, for the varying rate of self discharge to disrupt the balance to the point that this replacement would have a short lifetime. You can recondition cells in a junkyard battery to restore some chemically lost capacity (this is what I do, along with ReInvolt and Battery Boy), and thus have better performance, but it would take a long time with just 1 charger.

If you buy modules on ebay, with the intention of replacing 1-2 bad ones, then using a charger/discharger is a must. Every battery that has a bad module must have at least a few good modules tested, because there are two battery failure modes. The first is a random failure, which is what I would expect to see in failed batteries in northern latitudes. The second is chronic overheating, which, dammit, is what I see a lot of around here, and what I suspect is the primary failure mode for the Sun Belt and in the Rockies. In the overheating case, the central modules have almost no capacity remaining, typically less than 1 amp-hour, while the outer pairs (1-2, and 27-28) can be restored.

You may ask, how is it that the battery overheats? Well, there's a couple things that happen. First, the fan can become clogged with lint and other debris. That eventually triggers a code, but it makes the battery highly vulnerable to overheating. Second, as the battery ages, there is a mismatch that develops between calculated SoC and actual SoC. The battery tends to get a full charge with less effort. Parking an older car with a full charge is extremely detrimental, because the NiMH charging chemical reaction becomes highly exothermic at full charge, and the chemical reaction continues for some time after the charging current is removed. When parked at full charge, the chemical reaction keeps giving off heat for as much as an hour, while the battery fan is now off. At some point, the heat causes pressure to build inside a module to the point where it vents electrolyte, and capacity is lost. This is why, especially in the summer time, the battery fan will kick on to high in older cars that have been parked at full charge for about an hour. If you find this happening to you, do everything that you can to avoid that situation, because every time it happens, damage is being done.