Also, The vesc fets switch battery power directly to motor phases. If the motor shorts, it could blow the fets which usually fail closed (connected). Mayhem could ensue. IMO fuse is mandatory on battery power leads.
+1
@b264 are you trying to get me off on my rant about monitoring vs BMS again?
I bought one of these, pretty awesome!
I made an adapter and plugged in three 4s lipos, one of them 0.1v higher than the others. The balancer drained a high cell into a supercapacitor at 2A, then drained the supercap into a low cell at 2A. The current is adjustable, everything looked beautiful in the android app. Still testing but so far beautiful. Perfect device to charge to 4.1v/cell and periodically balance the pack. There’s a 1A ($90) and 10A ($500) version. Oh I see now a 5A version ($300).
IMO charge only BMS does not give you that much protection, and the way it balances packs wears out cells prematurely (slightly overcharge all cells and drain them back down, repeatedly over a long period). It’s not much different from just using a balance board. Or IMO just charge to 4.1v/cell and check cell voltages periodically.
The smart bms is more useful for the monitoring than for the balancing and the protections. IMO if there was a tiny version that removed all the power switching and balancing circuits, and added a buzzer, wow that’d be awesome. I know I don’t know enough to make it happen, but I’m looking at this chip that’s on the smart bms, which is only like $4?
Thors are 32V fuses and they as well don’t provide a fusing chart (after which time at which current they will trigger)
Better to use 58V midi fuses from mouser for 12s
It’s a personal thing, but if I use a fuse on the discharge side I don’t want to trigger it in the wrong moment. A blown fuse at full throttle is no fun at all, especially if strapped with bindings onto a 25kg board The extra 3$ are definitely worth to spend in my opinion.
It does. Read about it. But I wasn’t referring only to the voltage rating only. I just don’t want to trust a fuse rating from a chinese company which even don’t provide a fusing chart. What if the 80A fuse is in fact only a 35A fuse because if no quality control?
It’ll blow based on the current, and the voltage across the fuse will usually be a mere fraction of the voltage rating. The rating is important for making sure the fuse doesn’t arc after blowing.
this is the reason i run my bestech HCX-D223V1. it has an eswitch which makes life a whole lot easier, has individual cell voltage discharge cutoff, up to 20a charging, 80a discharge and purely piece of mind. also it only charges to 4.15v i believe so you have headway up to 4.25v where the overvoltage cutoff is
Stating it just like this, without mentioning the arcing hazard, is a big omission! Also AC vs DC voltage rating matters for similar reasons - AC tends to self extinguish the arc because it crosses zero volts.
The extra 3$ are definitely worth to spend in my opinion.
