UPDATE 2012/2/1(problem in thread title has been resolved): I have a question for you guys/gals. My charger cuts off at 42V but my pack should be charged no more than 41.5V, is there any way to lower the voltage of the charger by 0.3-0.5 V? I've tried using a diode(0.7V voltage drop) to take it down to 41.3V but the charger won't turn on again unless it drops below 41.1 V. This may be a problem because this battery is in series with another battery that stays at 41.5V off the charger so thats almost 0.5V a difference. I would like to keep the two batteries balanced.
UPDATE 2012/1/10: Good News and Bad News! The MK II controller runs well! I was very happy about it.
The Bad news, in my infinite stupidity I hooked up the charge leads backwards on the external battery and now the BMS won't charge the battery anymore
I went ahead and hooked up the charger directly to the battery, which brings me to my....
Question: Will an A2B battery be ok being discharged and charged completely BMS-less for some time??? The BMS is actually still hooked up, including the balancing leads, but the red charge wire has been connected to the battery main red wire. Charger is 42V 4A. When I hooked it up w/out BMS the battery was at 40.8 and the charger was trickle charging it at 2.8A.
Voltages of the each string are on last page. Pictures of the BMS are at the top and pics of the cells are bottom of the first page.
I'd like to go with a replacement BMS by some other manufacturer. Last time I tried to get a replacement BMS from A2B they wouldn't give it to me. They insisted I send in the entire battery. kind of a waste of my time and money.
UPDATE 2012/1/9: i don't know why my lyen mkI (infineon) cant run the BMC and MAC gear motors at high voltage. Lyen and I couldn't figure out the problem so I spoke to some others and to Ilia at ebikessf.com and i ended up purchasing one lyen mk2 controller through ebikessf.com. thanks for same day shipping.
Question: should i leave the BMSs Bypassed for discharge or should I reconnect them? These are lithium manganese as far as i know. Reconnecting them for discharge means i have to reinstal the diodes that protect the BMSs incase one cuts out. Its very tight fitting those diods and a relay into the bottom of the A2B frame. would like to avoid all this work if there is very little chance these packs could get unbalanced and one falls way beloe lvc. They will still charge through theyre BMSs.
UPDATE and summary: With bypassed BMS on two a2b batteries at 72V I have in series and a no load current of 1-2A spinning smoothly at full RPM... the BMC 600w-T motor stutters when under load at low RPM not with low current usage. It also does this when powered by a 60V 5A power supply when powered by the batteries @72V with a MAC motor. However when powered by one 36V battery the system runs properly and smoothly with both motors... whats going on here
I have an A2B metro with both batteries, Lyen 9fet controller, and the new generation BMC 600W torque motor. A huge thank you to Lyen for helping me out finding the problem, definitely buy controllers/things from him if possible.
I recently finished hooking up the two A2B batteries in series using a Diode in parallel with each battery and I nice relay for my on off switch. 83.5V fully charged
...However I am having intermittent current issues. The motor runs smoothly no load, but stutters and is underpowered when under load. If I disconnect one of the batteries and run it at 36V it runs smoothly. It's probably the BMS. Does anyone know if theres a way to remedy this and avoid bypassing the BMS during discharge?
This is video of no load test. Its not the best quality video but you can hear the motor stuttering when I hold the break:http://www.youtube.com/watch?v=JYJyybWwxz8
Picture below: BMS of A2B External Battery. Charge leads connect in the bottom right. Main battery leads top right and bottom left.