Help me not burn my Vesc’s or board please!!! I have 2 Li-ion batteries that have their own individual BMS that controls charging and current output. I was initially going to use one, but they are only rated for 15A discharge which is abysmal. I want to put both on the board but not run them independently of eachother. I want the 2 Vesc’s with their own dedicated battery. I know I need two power switches, but can anyone come up with any downfalls to this design. I never plan to run the board without both on and plan on connecting the vesc’s with a canbus cable and having one designated master and the other slave. I read that if i don’t do that, there might be motor sync issues on my dual motors. Please help!!
I would really like to use these batteries if possible considering I already have them.
tell us more about your poor batteries
Not a direct answer to your question, but the 15A discharge bms will very likely cut off your battery on every hill you try to climb with it.
I got the packs as compensation for work I did at the local college and they are 10s 3p packs with their own bms for charging. Panasonic cells, I will have to check the specs on them again. High quality cells regardless and can do more but the bms limits them. I really don’t want to disassemble the packs considering they are in custom made plastic molded packs and are water tight which is a HUGE factor in my design. I am mostly concerned about the vesc setup, I read that you can burn the vesc with this setup. I then heard that it will be fine. I dont really want to go experiment and know I am not the first to try this, just not sure who to ask.
IF i were to think that this is a good idea, i wouldn’t use can-bus but independent receivers bound to one remote…
if the VESCs are not connected in any way physically, you can’t burn them up, especially running only 15 amps thru them…
If one side is on while the other is not, the chip used for canbus fries itself. Never have two sides connected with canbus if they aren’t connected to the same battery. What you should do instead, is this:
You should also parallel the charging cables of the two batteries and use only 1 charger and have only 1 charge port, which is connected to both batteries.
then you could run one motor, the other motor, or both
should is completely the wrong word…
could
is a much better word to use in this circumstance
especially considering you will be essentially connecting the two batteries together via the charge port… i can see unintended consequences doing this if not done properly…
no, because the two BMSs have to receive the same charge. Otherwise the charging current would only go through one BMS, and the other battery would be charged via the main battery leads, getting unbalanced over time. Most BMS can only balance while charging current is going through them! The only way that charging current is going through both of BMS is to charge the two packs through the same port.
think about it for just a second…
you are running 2 15amp batteries in parallel with only the tiny charge port wires connecting them…
what could possibly go wrong
No, the main leads also have to be paralled.
My E.E. buddy said that design will likely burn up my batteries otherwise that would be ideal.
wrong answer… the charger wires are connected to the mains
Isn’t there a separate charging port on most BMS?
Oh, than you shouldn’t connect the vescs at all. And either use split PPM or two separate receivers (with a remote that can send signal to two seperate receivers at one time)
it CAN be done, with components… but why…
disconnect the batteries from each other and run independent receivers… you will not run anything up
My EE buddy said that the independent design of the batteries is by far the best option for the batteries, just not sure how the vescs will handle it. I think the single remote paired to two receivers is my best option. Does anyone know what remotes will do that or how to do that?
