06 HV Battery Module Replacement

Change out module 8, charge and balance with a grid charger.

While the battery is taken apart, you may want to clean up the copper bus bars. Remove them and soak them in some vinegar overnight then reinstall

 

Yes and yes

 

I would charge up the battery until the voltage stops rising and then continue to charge for another 4-6 hours before doing any discharges.

I find it interesting that block 4 is showing similar voltage drop to block 11. Also of interest is the symmetry, in that block 4 and block 11 are the 7th and 8th modules from their respective ends. to me I would say block 4 (modules 21 & 22 as marked) is going the same way as block 11, so if it were me, I'd get three more modules that have similar characteristics as your current modules and change out 7, 8, 21 & 22, seeing as you have the battery out an dismantled. My feeling is if you don't, you will get to do this all over again, very soon.

I would observe (using Techstream or Torque Pro) how the modules are behaving once I had it back together and the car running. It would be easy to see if the "new" modules are working well with the "old" ones.

It is not just voltage that is important, it it the rate of voltage drop/increase (in relation to its peers) when the modules are discharged and charged.

 

Lowered capacity in block 11 can be fixed with the discharges. You can test again after reconditioning and balancing the pack.

Putting in new unknown capacity modules can be worse than reconditioning the existing ones.

 

Agree 100% which is why I said:

 

I agree with @JC91006 and @dolj. Charge first before discharging per the Prolong instructions. And do that before replacing parts. Then replace parts if you still need to.

But a good cleaning while your in there is also a good thing. Also, take a look at the crimp connectors for the communications wires as well as the power cables.

 

Charge them so the resting voltage is the same as the average of your good modules and then apply the same load test. Don't use any that have a significant variation, either significantly higher or lower the the rest. It doesn't necessarily mean you need to bin them, but you need similar characteristics if they are to work well with the others. A better module can be as bad as a worse module when put in with existing modules.

 

dr3, Here is the deal. Out of those 28 modules in your ORIGINAL 2006 battery pack, #8 has failed. It's done, gone, over, get rid of it. In my experience of disassembling/testing/rebuilding batteries, the remaining 27 modules will vary in capacity from ~1500mah to 6000mah. That means that even though they are at a similar voltage, some capacities will be as low as 1500, and some may be as high as 6000. There's no way to tell which module has what capacity, unless you test cycle each one individually. That means you would need to buy additional test equipment=$$$. My testing has also showed that this variance (1500-6000) can be tightened up significantly (to withing a few hundred mah) by discharge/charge cycling the modules several times. The grid charge/discharge accomplishes the same thing, it just does all modules at the same time instead of individually. The situation you are in right now, following module 8 replacement, is ideal for the grid charge technique.

 

Unfortunately there isn't a "standard" for assessing modules.
And the ring lies the problem.

I use my own method for the ones I sell but it may not match the customer's methods. I may use settings for charge/discharge but they may be doing something completely different.

There really is no good way to make sure that you get modules that are as equally degraded as the ones in a failing pack. Unless of course you use the exact same methods. Even them sometimes equipment can have variability, so it would be even better if they were tested using the same equipment. But that is not reality.

Could a standard be created for equipment, methods, etc. I suppose. But getting suppliers to conform to it is unlikely. And if they have to do testing to match a customer's settings/methods, that could increase the cost of modules beyond what people will pay.

Even when I and other supporters of this forum sell tested modules for $50 including shipping, many people balk and instead choose go to random people on ebay since the cost is less. (sometimes the even choose to buy from sources that have already been confirmed to rip off other members of the forum with poor workmanship.) But life is about choice and that simply is what it is.

As much as possible, I prefer to sell customers sets of modules that all come from the same pack. This can help limit the variability.

 

Here is a spreadsheet from a 2007 HV battery I'm currently cycling. Column 'a' is the first measured discharge. This is straight from the original car, and shows what energy that module contained. It's easy to see module 14 is the problem. Using only that information, it would be easy to say that module 2 and 16 should also be replaced. BUT, column 'b' shows the capacities following several deep cycles. #16 doesn't look so bad anymore, does it? Modules 2, 25 and 27 are currently cycling, so those values are not available yet.


..........a...........b
1.....4438.....6397
2.....1635
3.....3562.....6386
4.....3918.....6298
5.....3758.....6496
6.....2912.....6412
7.....3909.....6481
8.....3621.....6414
9.....3400.....6520
10...1910.....6424
11...4009.....6392
12...3540.....6536
13...3837.....6437
14.....289.....BAD
15...4164.....6383
16...1479.....6399
17...3379.....6469
18...3769.....6392
19...2910.....6399
20...3990.....6438
21...2190.....6439
22...3552.....6343
23...3644.....6535
24...3822.....6447
25...3199
26...2755.....6325
27...3008
28...4205.....6339

 

The best you can do is compare them to each other. So they are similar-ish for now. Would be even better to let it sit for a week (or even a few weeks) to see how much they self discharge.

They look decent enough for now, but they will likely get out of whack again in the future if you don't implement some type of regular maintenance.

Also since you are going to installing modules from a different pack, you will be adding in even more variability that you will need to tamp down over time.

You are officially off and running on your exciting and never-ending game of Whack-a-mole.

Continue to play it as long as you are having fun and have the time the free time to devote to it.

 

And if you are willing to share ...
- Brand/model of module charger/discharger you are using.
- charge setting (amps)
- discharge setting (amps, minimum voltage)
- rest period (minutes)
- Active cooling during process (y/n)
- number of cycles

 

steel wool will clean it also.

 

It looks like some of the zinc plating is gone, but in the big scheme of things, they'll work fine. You can always check it out in 6 months to see if corrosion buildup is occurring. Be careful torquing them as to not snap a stud. That tends to make the job a little harder. Personally, I use a single purpose 1/4 inch drive torque wrench that's been calibrated to release at 48 INCH lb. The recommended torque value for that size fastener is 41 inch lb lubed and 54 inch lb dry. 48 puts it on the safe side of 54 and about dead center of the 2 specs. .

 

if you haven't assembled the pack yet, maybe you can buy some other terminal nuts? there should be members here with plenty of those available.