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Old 04-15-2014, 12:55 PM   #5 (permalink)
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Join Date: Apr 2014
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Reconditioning batteries

Well it has been a tough month for my battery replacement. I've had a battery pack that worked better, one that worked great and now battery pack is dead. I'll post what went wrong if I ever figure it out. But how to recondition batteries?

You can look around for details on how to remove the pack. I found a great youtube video for the pack removal in the civic. I don't know what it will look like for the accord but I assume it is similar. Warning the fully charged pack is 170V DC. It will kill you. Turn off the breaker. Then you are only exposed to 18V at a time.

Here is a picture of my charging setup /

You'll need a charger/balancer. I bought 4 cheap ones. Turnigy Accucell 6. The only downside to these is the max discharge is 5W so it takes ~12 hours to discharge a stick of 6 batteries.

So from the picture you can see the batteries come in pairs with the ends welded. Each stick is 6 batteries. I recorded the voltage of every stick when I removed it. Then I waited a day and checked it again. This will give you an idea if you sticks have a self discharge problem. Wait a week would be better

What did I do and what did I learn. I took each stick 22 total and ran it through a discharge/charge/discharge/charge cycle. All of mine were close to dead so the 1st discharge was ~0.

I discharged to 6V or 1V per cell.
I charge to a default setting of delta v 5mv per cell.
The cells are suppose to be 6500mah and you should set your charge max to 120% of that. So I started by setting my charge limit to 7500 mah. I had 1 cell reach a temp of 160F. So I aborted that and change to a max charge of 6500mah after that. I also changed my charge current from 5A to 3A.

So in summary you need to disassemble your pack and run them through the chargers. With 4 chargers I was able to do all mine in about a week.

What makes a bad cells? Discharge is low. All mine were about 4500mah discharge after a 6500mah charge. So pretty good. Self discharge. How much dose the voltage drop in time. A week is a good measurement.

One mistake I made was to put my old batteries back with 2 pairs replaced. Worked great for 1 day. The next day I had an IMA light. I took the pack back apart and the replaced cells measured 16V while the old cells measured 14-15. I think the problem was cells out of balance.

I'll post more if I get some success.
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