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Old 11-07-2012, 12:38 PM   #22 (permalink)
govman6159
Extreme DIYer
 
Join Date: May 2012
Location: Bowling Green, KY
Posts: 29

Custom eBike - '89 Bianchi Mainstreet 24vdc motor w/ 24v/30ah LiFePO4 Battery Pack

2006 Prius - '06 Toyota Prius 2
Thanks: 15
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Quote:
Originally Posted by Daox View Post
Do you have any form of BMS for your batteries?

I checked prices on the controllers on the electric scooters site. They're way cheaper than other ones I've seen. Is the quality any good? $30 for a controller makes me wonder.
Yes I have a BMS and his name is Govman6159 (lol). IMO, there isn't really a need for a BMS on this bike as long as I monitor cell voltage periodically. What I do is periodically monitor the individual cells as its charging. If I see one getting too high, I will stop charging that cell and continue charging the others. I am using a 24V/1.8A charger to charge the pack. I find I get nearly equal charging up to 27.1V (29.2 is the max for the pack). Once it hits that voltage, I have found it is at this point when cells may become unbalanced. So from this point forward I closely monitor individual cells. This has allowed me to id which cells are prone to overcharging (I only have one set of cells prone to overcharging). 27.1V is about 92% charge for the pack so I usually just stop at this point. I have found that by doing this, I get less than a .08V variance between cells (whereas .3V is considered normal).

As for the controller quality, I'm happy w/ the performance of mine. I've had this controller for 7+ years and its still working (YMMV). IMO it does a fine job.
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