Yeah, lots of experimenting to do now. BMSs are not rocket science too, I might be able to reverse engineer one that could activate a buzzer 30 sec before a disconnect. It's a lot of effort for the cause but I will test the regen on a lightly charged battery to see if it's worth it first.
sure...but you won't have 30 seconds if something goes wrong in ther and the bms reaches a limit. itt will disconnect immediately unless you are hacking it so it can't control it's FETs, or wiring around it.
also, as noted, it isn't just hte regen that could trigger a bms shutodwn. it is any limit in the battery that can cause it to disconnect the output. that could be temperature, voltage of any cell / group not just low or high, but also the difference between any two cells / groups, current, etc. could even be a software crash in the bms mcu that ccould cause a disconnect, etc.
testing the regen with a lightly charged battery is only going to test the regen itself, it will not test any of the failure modes nor will it test in the situations most likely to cause batteyr shutoff.
and if a bms shutodwn doesn't cause a voltage spike that nukes parts once / under one set of conditions, it doen'st mean it won'thappen at some other time with slightly different conditions.
there's no guarantee that any thing would ever fail or blow up...but it has happened often enough to know that it is a problem....
I did open my Sabvoton (likely knock-off) controller and found some of the cheapest capacitors I've seen in a while. I'm pondering the investment of $35 to rip out the trashy 470uf 100v ones in there for some quality 1000uf 120v rated ones.
i'd use rubycon or panasonic, etc. ther'es some capacitor discussions around that discuss various brands and properties.
for main power bus caps you usually want the lowest esr you can get, and the highest temperautre rating because thigns get hot in there and the higher the rating the more hours theya re guaranteed for near/at that temperature.
more capacitance isn't always better, but lower esr will help them do their job with less internal heating.
higher capacitance makes biger caps and so does higher voltage, so both together make even biggger caps. probably big enough they wont' fit vertically on the board anymore, and then you end up with long leads from end of horizontal cap down into the board adn those leads can then vibrate and break, or they can heat up with the current flow and fail, or at least impede the filtering effect they're there for, etc.
The next thing was the raw aluminum plate that is used as a heatsink inside. It's not even machined flat, it's raw stock. I'm itching to remove that and put in a piece of machined copper or at least just machining that one flat.
lapping it to the case surface it mounts to will help with heat transfer-by how much depends on the amount of actual metal contact they make now, and how much air is between them instead, vs how much metal contact they could have if they were properly lapped.
iff you go with copper y ou might as well go all the way and extend the bar out as a full heatsink, slotting the case to feedthe full size of the copper out inot the airflwo and fin it appropriately all as one piece. this will mean one less thermal gap to cross.