Hi all, just joined the forum because I haven’t been able to find any satisfactory answers to a BMS question elsewhere…
I’m currently building a 6S2P pack of 18650s for a small cruiser longboard and the more research I do about BMSes the more I get confused about how to use them. From my current understanding, all a BMS will do is cut power to a load if the current is too high or if a cell drops below some threshold voltage, and the BMS will use bleed resistors to prevent any cell from reaching a voltage that is too high. Is that all correct?
The issue I’m having is figuring out how to charge the pack. Obviously, one way to do this is with a balance charger, and that’ll work for sure. Another option I’m exploring, however, is using a bulk charger, which apparently is another valid solution. What I’ve gathered is that you can just connect a bulk charger (e.g. a 25.2V supply for a 6S pack) directly to the main +/- terminals of the battery pack, and the whole thing will charge correctly. Supposedly, bulk charging should charge up all the cells, and when any cell’s voltage gets too high, the BMS should take care of that, so in the end the whole pack is theoretically balance charged? It seems like this isn’t the safest way to do this though…I’m currently trying to use this BMS and if you do some searching online on other websites, there are mixed reviews about this BMS – some people say that bulk charging works fine, and others say it completely fails.
Does anyone here have experience using this particular BMS, and more generally, know how bulk charging works with a BMS, if at all? Thanks in advance