Tips or Tricks? Attempting a Gen II Battery Repair for the First Time

TL/DR: I am repairing a Gen II traction battery and am looking for recommendations on what tools/chargers to purchase. I am also looking for any tips or suggestions that may help the process go more smoothly.

Hi Everyone,

This is my first post on Prius Chat, though I've been lurking around occasionally. I own an '01 Prius and an '06 Prius. The '04 traction battery died about a year ago and the '06 just started giving me the error code of death (P0A80) before Christmas. I decided that with two priuses, and several more owned by family/friends, being able to repair a battery would be a very helpful skill, so I will be attempting to rebuild/rebalance my battery pack using the method outlined in this thread:

Gen II Prius Individual Battery Module Replacement | PriusChat

I've spent about 8 hours reading as many articles on here as I can about battery module replacement (the community here is incredible!), though I admit that I haven't even come close to reading everything this forum has to offer. I have a mechanical engineering degree and a basic knowledge of electronics, so I have high hopes of not frying myself or my traction battery during this project.

Which brings me to my request. I am looking to purchase the equipment I'll need to replace the bad cell(s) and rebalance the entire pack. Does anyone have any suggestions for good battery chargers that I can use? I am hoping to spend ~$200-300 on tools/chargers and ~$50-100 on replacement modules. Can anyone comment on the whether or not the grid chargers I see for sale here would be useful in my situation?

Thanks a ton in advance!! This is my first time attempting a project of this size and I am very much looking forward to it. Any help you can give would be appreciated, even if it's just "this thread has some good advice." If anyone would like data on my car, I'd be happy to share it. I have a friend with a techstream cable that came over and scanned my car today, so I was able to pull block voltages and error codes (P0A0F, P3000 and P0A80), but don't want to clutter up this initial post too much.

Best regards,

Seafoam

 

Hi Steve,

Thanks for the tips. Here is a picture of the Techstream results on the battery voltages:

From this, I suspect that at least one of the modules in battery block 13 is bad. Am I correct in assuming that the grid charger probably will not be able to fix this for me? I would love to not have to have my wife's car down for so long, but I don't see how a charger can fix a bad module.

Thanks again,
Seafoam

 

No, I did not. I might be able to try that tomorrow, but the techstream laptop is owned by a friend of mine. I did not know that techstream could take real-time data. It was explained to me as just being able to pull error codes and the information on the car when the code was logged. Is there a thread about the techstream where I could educate myself on it?

The grid charger will be more successful than balancing each individual cell?

What exactly does the grid charger do? Forgive my ignorance, but I can't seem to find a good technical explanation of how it manages to charge/discharge the individual cells. Is there a thread or a link that explains this (again, not trying to be lazy, just haven't been able to find it yet)?

Thanks a ton for your responses Steve. They are much appreciated.

Edit: I just ordered my own MiniVCI. It should arrive on Tuesday, then I'll do the force charge and (hopefully) get the voltages from techstream.

 

Hmm... good to know, thanks. The grid chargers at HA are looking really tempting. However, part of my reason for wanting to go the DIY method instead of forking $3400 over to the dealer was that I have a Gen 1 and a Gen 2 Prius with bad batteries, my dad has a Gen 3 and my father-in-law has a Prius C (I may have been something of a Prius evangelist up until this point...). My hope was that I would be able to service all of their batteries in the future with the equipment I buy for this repair, but it looks like the grid chargers from HA each only work on one generation of Prius. Are the grid chargers easy to build DIY? I seem to remember you posting an equipment list somewhere, but I don't remember exactly what level of technical knowledge it required. I am assuming that the main difference between the HA chargers for different gen's is that they have different wire harnesses. Would it be possible to convert an HA charger to service any generation of Prius (1st, 2nd or 3rd)?

 

Thanks Steve. I posted a reply in the HA grid charger thread. Looking forward to setting up the techstream tomorrow evening, though the negative temps here may put a damper on that...

 

Thanks for the advice Brad. Quick question: I was under the impression that one is not supposed to mix Gen I and Gen II battery cells. Am I mistaken on this point?

 

Hi wddanie,
Sorry for taking so long to reply to this. I was all set to go the diy method on this when life hit like a ton of bricks and I realized I would not have time to complete the repair in time to get my wife's car up and running again. Fortunately, one of the forum members that lived near me offered to do the work at a very reasonable price. (I will let this person reveal themselves if they want to.) I have been back on the road for about a month now with no problems.

I am currently in the process of diy fixing my gen 1 prius though. After I saw the work being done, I realized that it wouldn't be as hard as I had expected. I'll keep this thread updated to let people know how it goes.

My best advice so far: don't let your car sit for a long period of time, and don't be afraid to dig in and start taking out the back seat of your car. For me, the first step was the hardest.