Traction battery rebuild at only 106k mi!

Hello all,

My daughter's '05 with only 106k mi just got the red triangle. I guess the heat in the deep south takes its toll.



Block 11 is the obvious culprit. It's the highest when charging and the lowest when not. I'll pull the pack tonight and get it on the bench. I'm sure a voltage test will pinpoint the bad module, but can anyone give me a head's up on exactly which 2 modules make up block 11?

Thanks,

YY

 

Yes, let's go with the guy with 100 rebuilds. And it turns out strawbrad is right. Using his numbering method, block 11 would be modules 21 and 22. Guess what? Mod #22 is reading over 1.25v less than all the others, so it's a no brainer; it's sticking out like a sore thumb.

Here's my parts battery:


This is my 3rd rebuild. If you need a good laugh, check out my 1st try a couple of years ago:

Traction battery rebuild question | PriusChat

Everything that could go wrong did go wrong. It ended ok though, I just sold that car this week after putting 24,000 miles on the rebuild and it was still running strong.

On this job I'm going to replace the bad module and do this:

3 discharge/charge cycles on each module.
.7 amp discharge to 6v.
5 amp charge to 7500 mah.
5 minute rest.
720 minute timer.

This is what I did before. If there is a new, better way, please let me know. I read somewhere to only charge at 2 amps, but that would take forever. I only have 4 DC-6 chargers and would like to complete this in 2 weeks or less.

Since this car has such low mileage, I'm tempted to just replace the one module and button it up.
Any thoughts?

YY

 

My parts battery has been sitting in the garage for over a year. The guy I bought it from on Craigslist probably had it sitting for a year or two. Last year, on my 2nd rebuild, I ran all the mods through several cycles and recorded the final voltages, capacities etc. Tomorrow I will look at my list, and see if I can find one that is still reading 7v+.

If I remember correctly, I suspected the CL seller was less than honest (what? Say it ain't so). He said his battery went bad, he was going to rebuild it, but decided to buy a rebuilt one instead, he somehow managed to keep his core (huh?), and just needed to get rid of it. I expected to find many good mods, but most were shot, kinda like he had already pulled all the good ones and filled it with known bad ones. He prob owned a fleet of taxis and these were his million mile rejects. And I drove 2 states away to get it. But if I get another mod or three out of it, it was well worth the $150.

Hopefully I can find just 1 more.......

YY

 

Good news, the spare pack is better than I expected. The first 7 or 8 were bad, very bad, 1-4 volts, like the Craigslist seller had pulled the first few on the end out and replaced with bad modules, just to make a full pack he could sell. That's what I was remembering. But the other 15-20 or so all measured between 7.4 and 7.8 volts, after sitting 13 months. So life is good again!

I'll start cycling today. If the mods in the battery I'm repairing all have good capacity, I'll just cycle them once or twice.

Thanks,
YY

Strawbrad, is it ok to charge at 5 amps?

And away we go!!





My parts battery notes from last year.

YY

 

Ok, I may have some problems. I'm going through the modules in the battery I'm rebuilding and I may have something in my chargers set wrong. The discharge went good, but something is happening during the charge and they are charging very quickly. The discharge took 6-7 hrs, but the charging took a fraction of that. Or can these batteries really be this bad?

Mod #1 4663mah discharge 2679mah charge
Mod #3 4463mah discharge 986mah charge
Mod #25 1878 disch 2741 ch
Mod #27 3865 disch 828 ch

5 amp charge to 7500 mah
NiMH Charge: auto
720 min timer
10.00v low input cutoff
Delta Peak: default

Either I'm doing something wrong or these mods are not as good as I thought. I'm running another cycle. Perhaps I need to be charging at 2 amps?

YY

 

Brad,

I'm not sure what the default Delta Peak setting is, but it can be adjusted from 5-20 mv/cell. I don't know which way to adjust it. I've always left it on default, but this very well could be the problem.

The chargers are set on a 10v low input setting, this has not been an issue since I went to two 12v batteries. With just one I used to get low voltage errors all the time. They read 12-13v every time I check them. This is not the problem as the chargers are finishing their cycles, just with poor results.

In fact the results are so bad, it's actually encouraging. If these modules were really this bad this car wouldn't even run:

Mod #1 4663mah discharge 2679mah charge(1st charge), 2588-7500(2nd charge), 5511-7500(3rd charge) (decent)
Mod #3 4463mah discharge 986mah charge(1), 1019-842(2), 865-1669(3), 1640-902(4)
Mod #25 1878 disch 2741 ch(1), 2302-2397(2), 2213-793(3), 789-3215(4)
Mod #27 3865 disch 828 ch(1), 924-1860(2), 1891-615(3), 672-1734(4)

Mod #7 1919-1648(1), 1756-5363(2), 3224-5305(3)
Mod #21 3845-555(1), 604-509(2), 600-635(3)
Mod #23 3134-209(1), 223-994(2), 1046-117(3), 110-1257(4)

The charger that did mod 1 is now charging mod 5 and it's taking much longer than the others. Perhaps 3 of my 4 chargers went bad just sitting? Unlikely, but possible. When mod 5 finishes I'll post the results and see if I can find any difference in settings between the 4 chargers.

Can anyone recommend Delta Peak settings?

YY

 

Thanks, guys. I'll do a round with the Delta Peak set to 20 mV at 2A and post the results.

 

Earlier; Delta Peak settings at "default":

Mod #1 4663mah discharge 2679mah charge(1st charge), 2588-7500(2nd charge), 5511-7500(3rd charge) (decent)
Mod #3 4463mah discharge 986mah charge(1), 1019-842(2), 865-1669(3), 1640-902(4)
Mod #25 1878 disch 2741 ch(1), 2302-2397(2), 2213-793(3), 789-3215(4)
Mod #27 3865 disch 828 ch(1), 924-1860(2), 1891-615(3), 672-1734(4)

Mod #7 1919-1648(1), 1756-5363(2), 3224-5305(3)
Mod #21 3845-555(1), 604-509(2), 600-635(3)
Mod #23 3134-209(1), 223-994(2), 1046-117(3), 110-1257(4)

After changing DP settings to 20 mV, charging at 2A:

Mod #1 Looked good the first time around so I didn't balance it again
Mod #3 850-7500, 5776-7500, 5680-7500
Mod #25 2895-6175, 3902-6169
Mod #27 2024-7500, 5651-7500

Mod #5: (lost data on first 2 charges, but looks good), 5198-7500
Mod #7 3523-6131, 3994-5134, 4125-4197
Mod #21 5012-7429, 5173-7148
Mod #23 4626-7187, 4971-7329

As you can see, the numbers look much better. The odd thing is, during my previous 2 rebuilds, the DP was set on default and worked fine.

Brad, mod 7 still looks squirrely, but what about mod 25? Good enough or replace it? I'm going to go through all 28 of these modules before I decide which ones to swap out and break open the pack.

At 2 amps, this is going to take weeks. Fortunately, I have a spare high-mileage-but-great-running 2005 Prius that my daughter can use, so downtime is not a major issue. I should probably upgrade my chargers. Maybe buy just one extra unit that can charge multiple modules at once and has it's own power supply. The Thunder T6 seems to be sold out everywhere. Any recommendations?

YY