module capacity gone

Hello

I have a 07 prius with 113k miles. It recently displayed the red triangle with code p0aa6 sub code 612.

I took apart the battery and nothing looked corroded, then on the inside of the bus bar i found a small amount of corroadion. After testing the cells i found 2 modules that were leaking voltage.

Since I had everything open I figured I might as well test to see if any cells were on there way out. The static voltages were pretty close around 7.8v, there were a couple modules that were .3v apart that I'm doing more testing on. I load tested each module with 1a, is 1 amp enough for a load test? I have a 100a load tester but figured that was way too much. They were all ok under load test, dropping about .6v and returning to original voltage within a few minutes.

Then I decided to check capacity on the bad cells, they were about 500mah, got to 1000mah after 1 discharge/charge cycle. I tested the capacity on a cell I thought was good and so far it discharged about 1050mah until it reached 6v, this was from 7.77v. I'm giving it some time to rest to see if it goes back up a bit and then I'll discharge some more till it stays at 6v. Even if I get a little bit more in it will be way under the 6500mah it should have or even the 3500mah that I've read is acceptable.

Since all of thr modules have parameters that are pretty close I'm thinking the capacity will be pretty close as well. Is it possible that all the cells are bad? Is it possible that it was operating normally with 1000mah capacity?

I'm hoping that I'm missing something or doing something wrong. Any advice would be appreciated.

 

Thank you for the input. Here were the voltages when I opened it up, I took the two modules that we leaking voltage out.

1. 7.87
2. 7.92
3. 7.87
4. 7.78
5. 7.71
6. 7.76
7. 7.8
8. 7.79
9. 7.65
10. 7.78
11. 7.83
12. 7.81
13. 7.8
14. 7.8
15. 7.76
16. 7.79
17. 7.81
18. 7.72
19. 7.76
20. 7.78
21. 7.86
22. 7.78
23. 7.71
24. 7.77
25. 7.86
26. 7.9

I have a b6 rc charger that can charge at 5a and discharge at 1a, only 1 cell at a time. I wasn't planning on balancing and reconditioning the pack initially, I was thinking I'd just find the voltage leak and be done with it. Now that it looks like I will be reconditioning the pack I will either be buying more rc chargers or a grid charger, what would you recommend?

I have a 100a 6v/12v load tester for car batteries. I don't think me modules are healthy enough to handle this.

What are you using for a 20a discharge?

I have techstream but just got a new computer that is 64 bit and I haven't had time to get the vci driver to work yet.

What would you recommend I do next?

 

The 2 modules I took out had voltage readings when I tested from the terminal to the case, there voltage readings weren't really that low compared to the others. Are you saying to reinstall those?

Most of the grid chargers seem to need seperate dischargers. What do you use to discharge and measure capacity?


Thanks for all the help!

 

I'm not at home but I believe they were both close to 7.77v

 

If needed, which it sounds like I do, i was looking at the hybrid automotive prolong grid charger and it comes with a connector to discharge it with light bulbs. It's in my price range of about $500. The problem is that I can't measure the capacity while discharging and I would like to discharge at a higher rate.

Do you guys have a better option for charging and discharging?

 

I did read through that thread yes. I couldn't find any substance on the modules other than some dust. I did try cleaning them anyway but they still had voltage leaking. The other 26 cells appear to have no voltage leaks on either terminal.

So im testing one of the modules that seemed ok. I discharged to 6v which was 1100mah, then charged to 8v which was very close to 1100mah as well. I discharged to 6v again which was 1300mah. Now I am going to charge again.

Should I be using different voltage limits?


I did a load test with 100a for 5 seconds on 5 and 9. 5 started at 7.64v and ended at 7.18v, it dropped to 6v while the load was on. Module 9 started at 7.66v and ended at 7.21v, it also went to 6v during. Module 2 which I think is a good module, started at 7.76v and ended at 7.45, dropping to 6.6v during.

Do these numbers indicate bad modules?

18 and 23 look a little low as well, replace?

I just placed the order for the grid charger and discharger, should get it next week.

Sorry for all the questions but you all have been very helpful!

 

My friend gave me a spare pack he has, minus 4 modules, so I can take whatever I need from that. I'll get everything put back together so that I can charge/discharge it when then charger comes.

I have 150w bulbs and 60w bulbs but I can't find 15w, will 25w bulbs work?

Even with the threads about getting the driver to work I'm still having trouble, I have some time tonight so hopefully I'll get techstream up tonight.

 

Some updates:

Since I was charging my modules wrong I don't really know the capacity of any of them. I was just charging to 8v instead of sensitivity or capacity cut off. I remember using that b6 charger for rc batteries and it would never cut off from the 7mv sensitivity cutoff so I was nervous to leave it up to that.

I charged a questionable cell at 5a with the limit set to 8450mah. I wasn't paying close enough attention and it puffed up. It had charged about 4000mah and was at 8.55v.

Tested all the modules on the new pack, they were all lower than mine but pretty close to eachother about 7.48v to 7.50v. One bad module at 7.23v. They held up better under load than the modules in question on my pack.

So I replaced the 2 leaking cells and 4 cells that were low voltage and weak under load 5, 9, 18, 23.

I don't think the modules from the new pack are in good shape but they are seemingly better than my bad modules.

I put it all back together (miserable) I think I bent the case a little when I had part of the pack on the edge of the bench when I unscrewed the bottom of the modules. So getting the screws to match up was a battle. Finally got it back together and equalized it by connecting in parallel.

I put it back in the car to see if my error codes would return and they didn't! So far no more isolation fault.

25w seems good then, I'll pick some up.

I was noticing lower mpg than normal before all of this and I can't imagine it was from the leaking modules. So im hoping it will get better after reconditioning.

Now just waiting for the charger so I can recondition, balance, and get it back on the road.

No luck with techstream yet but I didn't spend that much time on it, so hopeful I we'll get it working before I get the charger. May have to buy an older cheap laptop or something.

Thank you!

 

I wasn't sure about starting it up while everything was out of balance so I was hoping the paralleling would at least allow it to start without a code and check for the isolation fault. Your definetly right about it being unreliable. I didn't have them hooked up in parallel for that long but some modules were already off be .01v within a couple hours.

I forgot to mention one more thing. When I pulled all the modules out I noticed a stain in the case that looked like some liquid had been in there. Couldn't see it on any modules or tell what it was but maybe it had something to do with the fault. I uploaded a pic below.

Do you think that the recondition and balancing will give a significant increase in mpg?

 

That's encouraging, I plan to do 3 cycles. Starting with 150w bulbs to 170v, then 60w bulbs to 140v, then 25w bulbs to 100v. Not sure about the voltages I'm going down too, it seems like you would go more aggressive?

Finally got techstream up, was time consuming but worth it. The instructions online actually worked perfectly I just didn't understand them the first few times. Looks like my spread between blocks is .3v at idle and about 230v before conditioning. Should have charger tomorrow.

 

Greasemonkey, Thank you I got it working without a virtual machine.


Steve, I think I misunderstood the instructions. I though I was to fully charge/balance, then discharge with the 150w, then charge/balance, then 60w discharge, then charge/balance, etc.


Now it sounds like it's just 1 discharge while switching bulbs at each voltage threshold?