Tinkering with HV module reconditioning but not seeing improvement

I am no expert on this subject, however I have read just about everything there is on reconditioning of said traction battery in the Prius. As long as your chargers are working correctly, I suspect you simply need to obtain some stronger/newer modules and go ahead and replace those modules you referred to. Some have found that charging cycles are better if you do it more than three times. Keep track off all the voltages on each module. The ones that don't respond more than likely need to be swapped with newer modules. After that charge all of them, and then finally connect all of them together such as has been shown in the various strings to balance the voltages between all of the cells/modules. I can't recall if it is "series" or "parallel" that you tie the cells/modules together to get the traction battery to balance. Once all of the modules are recharged satisfactorily and the entire pack is rebalanced, you should be at the point whereas the traction battery has been "reconditioned" and the use thereof should be close to original equipment as far as power and reliability is concerned.

I hope this information helps you. Good luck in your quest. Many have been able to do this satisfactorily and saved an old failing pack. In doing so you do not have to spend the $3K for a new pack, but rather spend a little money on modules, and the time spent to do the work.

Be safe, remember Electricity can kill you. Respect that battery. More than 200 volts DC which is lethal if you get in the path of said electricity.

Peace,
Ron (dorunron)

 

It looks like those modules have very little capacity. That's unfortunate as they will need to be replaced. Do you still have your old pack?

 

And yes, it is possible that the old pack will contain more than one or two weak modules. This is what happens to the traction battery over time. All NIMH batteries have a limited amount of charge/discharge cycles. Once the limit has been reached, the cell will begin to fail.

 

Good morning usnavy, excellent post and reply.

Ron

 

Where (geography) were these modules used? If in a hot climate or in mountainous regions (like much of Pennsylvania), they are probably all used up. When a Prius is used in cool climates on flatlands, most of the modules still have life in them when one of the modules dies.

JeffD

 

Sounds like you do have quite a few that are truly toast. Truth is there is no real minimum capacity as long as they are all fairly well matched (otherwise you can get weak block codes under load). I would aim for no more than 500 mAh variance between them if possible. Also you should be upping your discharge rate to 1A (0.07 is WAY too low.......rest of the settings look good though).

 

I have read a lot of posts as well but I think you may have misread the discharge amperage. When ryousideways did his, he used 0.7 amp discharge. He also used 7500mah I believe.

I was going to replace my modules but needed the car sooner than the time needed to rebuild it (Not I have a transmission issue that is keeping the car stationary for a while longer)

 

He used 0.7A because that is typically what the charger defaults to when set to 1A discharge (may be less if multiple modules are cycled at the same time).

The capacity should be set between 7000-7200, 7500 is too high and may damage the modules.

 

Sooo many things going on in this thread.

Is your charger going 2amps the entire charge cycle? In other words, at high SOC is it still pumping out 2 amps? I hope not.

No need to try to put 7500 mah in a 6500 mah cell. You are trying to overfill it waaaay to much, which is not a good idea.

.07 too low? Well, it's better than too high. Just will take much longer.
Also will give somewhat false readings in the sense that under low load a module will appear to have more capacity than under high load.

Was this pack sitting for a long period of time unused? Or is thisfrom a car you were driving until you started getting codes.

You say you replaced to modules. Was that during this round of tinkering? Or was that some previous round of tinkering?

 

Good info.
How long ago was the other module replaced?

It's fine to top off a bit above 6500mah to take into account inefficiency of the charger. But I don't think an additional 15% would be necessary.

.7 is much faster than .07. You should be happier with that.

5 weeks isn't too bad. Was probably helpful in highlighting the modules with high self discharge rates.

It is not usual to have so many fail at once, but it is possible. If you are having several of them fail you may be on the road to "whack a mole" city, which means you may end up opening things up again after this no matter what you do this time. Likely may not last a year before having to go in again.

 

I believe the 0.07A referred to discharge current which under normal use in the vehicle can hit over 100A so setting it to just 1A will not do any damage at all to any of your modules (charging current is a whole different ballgame though, the lower the better as Eric mentioned above........except at 0.07A charging it will be SLOW to finish the process).

 

With that mileage - there is a huge possibility that some modules lost their capacity significantly. The rest of the pack lost capacity - that is certain. Using donor modules with unknown capacity is waste of your time.
Last week I got a pack from 2006 Prius 250000Km (about 160kMiles) for testing with the hope to use that as a donor for another pack repair. Tested on 28Channel Analyser.
Two modules dead, two nearly dead and the rest of the pack showing huge discrepancy in remaining capacity of the pack. The best modules showed about 3.7AH.
Returned pack to the owner as it does not worth the efforts and can not be used as a donor.

 

Sounds like you are doing it properly but just in case here are the suggested settings for the charger.
Prius Battery rebalance thread | Page 3 | PriusChat

Kiwi, any chance the next time you run a test like that you could also try maybe 4 modules on one of those RC quad chargers we use for DIY and just see what you get for capacity on them? (if you need settings for it just let me know). Not that it will change anything for the DIY folks but would be a good experiment for posterity since you have much better equipment than most.

 

I have few RC quad chargers and one channel charger (those are used for our Quadcopter, RC car and electric byke with Bafang motor which will soon be tested on 5 Prius modules . I have not done comparison with the quad one but done it with the one channel device which I used as a charger connected to 19-ch Analyser and capacity measurements happened to be very similar. In that test batteries were Lithium not NiMH.
Can do with Ni-MH and probably this time will do quad one together with 14/28 channel analyser. Would be interesting.
The only issue - those RC chargers stop by detecting voltage changes and menu seems to have no option to change to temperature cut off only and deactivate voltage delta-v detection for NiMH.

 

That's certainly encouraging but hard to say how lithium tests might relate to NiMH. Would still be very curious how the RC quad charger fares vs the professional analyzer seeing as your setup is obviously much closer to actual use in the vehicle.

Here's the manual from the one most are using (including Hitec and Thunder), see page 10 for menu options:
http://hitecrcd.com/files/Hitec_X4_Manual_US.pdf

Like I said if you need any help with how we set up the quad charger before the test just shoot me a PM.

 

Thanks for the offer. Do not need a manual - Hitec or other RC charger - those I came accross although branded differently - all seems to have the same set up menu which is straight forward. The test I am planning to do will be 1 x NiMH 1.3Ah cell (1.2V) tested on 14-channel Analyser using RC charger in both charge and discharge mode at 0.5A CHRG/DSCH to speed up the test (can use Prius module but with bigger capacity it will just take more time with no benefit for the test). Test is aimed to check the recent release of the database functionality for our soft, but as a side result - a chance to check all of our RC chargers for accuracy.

P.S. last night dismantled for parts one of the server power units which has died - which reminded me to mention for those interested - look around for the server hot-swap power supplies as those can be used to power up your RC chargers. They are 12V and could be 50-60Amps and can be turned on without server equipment. Which will give you opportunity to set up maximum charge amperage on a quad RC charger when all 4 channels are used.