Hi to everyone, so after reading and researching I came with a diagram for my first build. It will be a 12s4p 30q dual focbox bms for charging and discharging and a e-switch.
Any suggestions advices corrections comments will be appreciated.
So this is it:
Nice man, Im doing the same except with a Supower BMS no e-switch (Antispark Loopkey is my switch). I would also suggest cell level fusing over the series fuse (Just cause thats what im doing on mine).
I’m not sure I’m following here… The diagram looks like charge+discharge and is how it should be set up if discharging through BMS. It’s either charge only or charge+discharge. At least I haven’t seen anyone going discharge only and then charging pack without balance charging…?
Only thing that is not necessary is e-switch, since a loop key is being used.
This confused me. From the image I see the Battery negative connected to the BMS at B- and the BMS negative connected to the VESC’ at P- and the charge port negative connected to the BMS at C-. The E-switch should kill the negative flow of current when in the off position thereby isolating the battery from electronics down the chain. That’s textbook discharge mode right?
Ahhhhh, I thought you meant the BMS was wired in discharge. I assume he just wants extra protection by using the XT90s loop key. Seems needless to me with a quality BMS, but I can understand wanting to protect a few hundred bucks worth of electronics
looks like eswitch is permanently connected then loop key is master switch. this is exactly how I’ve got mine wired up right now, same bms and all that.
only thing, I stopped using xt90s because they’re bulky. and once wires are soldered up they’re pretty long/tall. and doing the split to dual focbox as in the diagram, you’ll be surprised how bulky that loom becomes. I’ve switched mostly to bullet connectors.
I’d prefer to protect the human at all costs, even if it means overcharging the battery while braking hard. But there are many pros and cons to sort through, all depending on your preferance. I also like the BMS being physically smaller and not needing heatsinks on it.
If you want to use a loop key instead of the eswitch, put the loop key on the BMS P- to XT90 run
Also, this. Consider soldering them together too, instead of bullet connectors or the XT90/XT60/XT60 harness unless you have tons of space in your enclosure. I wouldn’t solder them together unless you use a loopkey though