****** - Verified Buyer
4.5
I needed boards that'll act as cheap, protective BMSes for a big pack.Plus points:- They work, they accurately stop charging current at 4.20v and discharge load at 3.0v.- They handle a beefy load of ~30a continuously -- ON THE LOAD PORT.- They handle a charge current of about ~15A continuously -- ON THE CHARGE PORT.- They can be reconfigured for lower numbers of cells, e.g. 9s, by removing components on the PCB similar to how other rows are unpopulated. Follow the example and it's happy to become a 9s BMS instead.Negatives:- They don't balance - they don't even try. Somehow this item is advertised as having balance capability, but it has no balance/shunt resistors, and it doesn't even make an attempt to do so in practice. Maybe there is some balance current there, but up against a 64Ah battery bank, it's like a dripping faucet filling a sink.- It seems to be susceptible to broken wires still allowing charging -- if a wire breaks (if a balance fuse blows, which seems to also be possible with this thing on the 1st/negative wire under some connect/disconnect conditions), the BMS will continue charging, no longer caring about that cell, it seems. Not entirely sure what happened there, but it happened twice. Maybe it just briefly used the balance lead as a current path when I connected the balance lead before the bank itself, when the load was attached? Maybe it'd still work fine, as it uses the main pack connection as the ground for sensing the first cell instead? Not sure...Anyway, they work, they're cheap, they're configurable, they just don't balance. Big whoop - if protection is what you need, and 4.2v-3.0v is the range you need it, this'll do the trick. Clever, passive, cheap little thing.
