The biggest mistake you can make if you plan to use them in series not to equalize them before use. They come in different state of charge. Maybe close if from the same lot but not close enough and I do not count on the equalizer. I start with a discharge to 2.5 V and charge two at a time in Parallel with a holder that I modified. Set a power supply to 4.2 V precisely and charge all batteries for that particular application with that setting. Bert Kehren In a message dated 1/23/2017 4:12:08 A.M. Eastern Standard Time, [email protected] writes:
I built a switched capacitor balancer. It takes some time to balance a wildly out-of-balance pack but does a great job of maintaining balance during charging and discharge. I run the balancer during pack charging and discharging. I tried it charging an 8S LiFePO4 pack with 7 fully charged cells and one fully discharged cell and it worked fine... no cells were over-volted during charging. It does not waste energy/generate heat like a resistive balancer. An inductive balancer can handle higher balance currents for very high capacity packs, but is also quite a bit more complicated to do correctly. Also built a processor-per-cell BMS using ATTINY-85's. I've used both on 4S32P / 8S16P A123 packs and ICR 18650 packs. Those A123 cells can dump 200A (each!) into a short circuit... you REALLY don't want to short a 32P A123 pack... They are also rather tolerant of abuse. A friend made a video of charging one at a 100C rate and it survived without exploding/melting. I once bought some that had been sitting fully charged for over 4 years and when tested still retained over 80% of the charge. A couple of charge/discharge cycles and they performed like new. I keep 4S1P packs in my cars for jump starting. There is a video of a guy in Canada staring his car over 10 times in sub-zero weather using one. The cells are 26650 size... are about the size of a D cell. ---------------- > The BMS doesn't balance the charge after charging (which consumes time & energy _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
