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Old 06-15-2012, 02:07 PM   #298 (permalink)
Daox
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Join Date: Dec 2007
Location: Germantown, WI
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CM400E - '81 Honda CM400E
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A small update here. I've recently been working on rebuilding my PHEV kit since I had some issues with it (caused by yours truely, no fault to Enginer) and blew up two cells a couple months back.

One step of this rebuild is evaluating every single cell in the PHEV kit's pack. The pack is made up of 32 "39Ah" Mottcell cells. The configuration is 16 in series, 2 in parallel. I've been using a Revolectrix PowerLab 6 charger to evaluate each cell. The process charges each cell up to 3.625V at 38A (~1C), then discharges it (I forget what voltage, I think its around 2.8V) at 38A, and then recharges it. The charger datalogs a bunch of data and tells you the Ah capacity in and out. The Mottcell cells I've found with this cycling setup only give a max of 34Ah of capacity. This is from brand new unused cells. Some of my older used (and abused) cells are showing capacities of around 30Ah. This is quite disappointing to see that you don't even have the rated capacity. But, its what I have to work with and it'll have to do.

The second step of the rebuild is to get the BMS' discharge protection put together and working correctly. This is the main reason I had the cells explode on me. I had overdischarged the pack and disconnected the BMS to get the charger to start charging things. I forgot to reconnect the BMS which provides charging protection and my two weak cells got overcharged. The next morning I found the mess. But, this emphasized the need for a fully functional BMS system. So, I will be working on assembling and getting the discharge protection working on the BMS. My thread for info on the BMS is here:

http://ecomodder.com/forum/showthrea...bms-20445.html
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