Review on 4S 100A 12V LiFePO4 Lithium Battery Protection Board LFP w/ Charging Controller and Balancing Function by Rashad Ross

This charge controller does what it says in the fine print, but still leaves a lot to be desired. I tested the controller with several LiFEPO4 chargers, a regulated current limit power supply, and a Fluke multimeter. I was able to insert 14AWG solid wire into the terminal holes as shown. I soldered all the wires and crimped the lugs for a decent 60A setup. I think 100A will push it, although I haven't thermally tested this unit. This controller protects the battery pack from overcharging. In my tests, once one of the cells is found to be above 3.75V, the controller opens the charging circuit and prevents further charging until the "problem cell" falls below 3.55V or so (in testing). To balance, this controller will NOT actively balance your battery cells while the battery is sitting straight. It only discharges the cells when the cell voltage exceeds a certain value (3.66 V for the highest cell voltage in my test setup). And the battery's "discharge rate" is only 36mA as stated in the specs and also measured during my testing. In order for the charge controller to "balance" you should always charge the cell with the highest voltage above about 3.65V. So if like me you have a big 80Ah battery some cells may be 20% unbalanced using a trickle charger it can take several weeks for the battery to balance. If that were the whole story I'd probably give the charger 4 or 5 stars depending on functionality and price (bang for the buck). But the charger only discharges cells above 3.65V, stops charging the battery once a cell's voltage exceeds 3.75V, and does not allow further charging until the high cell voltage drops below 3.55V a few days later and i see a charge/equalize/rest cycle, which of course occurs several times with longer and longer rest periods (when the highest cell voltage was between 3.55v and 3.65vc), my battery system is gone. Don't do anything with the highest cell voltage, which eventually settles at 3.57V. So basically, if I just pop my battery pack onto a charger, I can assume my battery pack will NEVER be balanced, since my battery pack always has one cell , which falls between 3.55 V and 3.65 V after charging, in this range where neither charging (due to previous overvoltage) nor active equalization occurs. Luckily I have a regulated power supply so I can set it to a voltage (currently 13.73V) that will supply my battery with around 30-40mA. and keeps the highest voltage cell constant at 3.65-3.7V. But I have to adjust the supply a bit every day. This is a super weak sauce. Not perfect. Perhaps performance will improve if all my cells are better balanced and only a few mA-hours are required from the cell with the highest voltage per cycle.