I've been doing a lot of testing on the new CALB SE 200a-h LiFePo4 cells, I did a discharge test to make sure the batteries were in acceptable condition. While the batteries were listed as "new" they were clearly used. I got them for a great price and luckily they still have enough capacity that I don't feel cheated (much). They were listed as 400 a-h and they tested to around 92% of that. I did my testing using a 1000W load via a modified sine wave inverter (90A @ 12V ~ 0.5C). I didn't take them much below 11V so I interpolated the capacity at 10V (completely discharged voltage). :
I complained to the vendor and they were happy to refund my money, I would just have to ship the batteries back on my nickel. That's Aliexpress; you rolls the dice, you takes a chance. Anyways, here's the Frankenstein setup for testing:
I'm using the iCharger to cylcle the battery back up, it does a great job of balancing the cells and charges at 30A. Right now my cell imbalance is only 2mV, which is awesomely low. You can calibrate the iCharger voltage sensing, which I did with my FLuke 115 so I trust the voltage reading.
I finally found a BMS that doesn't cost an arm and a leg (~$130)and does what I want. I hate BMS that don't annunciate anything, which is typical of most of the cheap chinese BMS. You have to get a multimeter out to see if they are working. The Electrodacus SBMS0 does everything I want, displays cell voltages, state of charge, tracks a-hrs in and out, and you can tweak the settings for about everything.
It also has contacts to control Victron battery disconnects so I can disconnect the load at low voltage, disconnect the charger at high voltage, low temperature charging disconnect, and control relays to do things like divert solar power for heating water when the battery is charged . It's got a few warts; it was designed by a microelectronics guy who doesn't know how to terminate power wires and the software is a little "kickstartery". But so far it is leaps and bounds better than anything else I've tried. The developer has a forum that he's very active on, he actually answers peoples questions. Try that with a chinese BMS!
He has optional modules that control solar panels, so you don't need an expensive charge controller. You have to use 36 cell 12V panels but it's so much cheaper (~$40/20A module) than a good controller so I'm going to try them out.
It has a WiFi connection and a web page so I can monitor the battery from anywhere on my cell phone. I just charged the battery so the cell voltages are out of wack. They settle back into balance after charging stops, which is a new realization for me. Don't do any cell balancing until about 12 hours after charging.
Helps me to get my geek on.
Bruce