I’ve read dozens and dozens of the countless posts on this topic and now i am adding one more for people to have to sift through (sorry about that). My project has been going on now for several months and I literally change my mind on size and type of battery pack daily. Now I’m at a point where I have to make a decision. I hope the picture I attached posted, but if not, I am building a mountain board which I intend to use on and off road. I am really not interested in going fast since I am old and no longer bounce. My dilemma is due to me weighing 230 pounds and even though I don’t want to go super fast I know that a higher voltage = lower amps which in turn = less heat. So naturally I think 12S, but then I get worried about how fast this thing will go so the cycle of indecision revolves. I’m sure that I am over thinking this. Please, before being harsh and telling to just use the search function, I have and most posts deal with you younger lighter (170lb-ish) folks and most seem to be on street wheels.
Here are my specs.
MBS ATOM mountain board
203mm inflatable wheels with - 84 tooth pully
Dual 6374 BKB 190KV 3200watt max 70amp motors -10 tooth pully
FOCBOX Unity on preorder
15mm wide belts
its also more risky. running at 12s is 84% of the vesc max voltage, id say 10s is a good balance of top speed and torque, but if you want pure torque 12s is definitely the way to go.
Why not 11s? If you can’t decide take the middle way.
But one thing I have seen is the 10th motor pulley. Are you sure that’s gonna work out.
It’s a very low count, so belt slippage could appear.
If so you will need to go up 14th or similar.
So top speed would rise and as you don’t want that I would rather go with 10s.
Never mind about 10s 12s where did you get that motor mount and far more info on that thing there is necessary. chop chop
Cool build btw and 12s or you will probably regret it. Just because the board does 40 mph does not mean you have to ride it at 40mph but the torque is easier to gear for with the extra voltage. Future proofing. Good luck.
@Andy87 look at me stalking the mtb threads lol
Fair warning the stock tires on the atom 90 are absolute shit. Wore to nothing in less than 100 miles for me, left me stranded on a group ride. Also you’re gonna want a bigger motor pulley for both speed and prevention of jet slippage. And go 12S if you can afford it, it’s more fun
With 190kv 12s lion 10:84 on 203mm wheels you’ll only get about 20mph. You’ll definitely want more than that. I say 14 or 15 tooth motor pulley and 12s (for less heat) that’ll get you to about 27 mph (maybe a little less because of weight)
At least on 10S I can gear the kind of speed i’d get on 12S, but not only am I already pushing more amps for the same wattage on 10S than 12S, gearing for speed on top of that just further increases the amp load.
It depends what you want to use this for. If you want a toy, probably 12S, if you want a tool, then 10S.
I’d go 10S. 10S is ridiculously fast, don’t let anyone try to tell you it’s not. 12S is 20% faster than “ridiculously”
You’re feeding hard square waves into inductors with hard absolute maximums of 60V on the gate driver pins. If you exceed 60V for a millisecond, it’s toast. Current and voltage have different failure modes. Overcurrent breaks things slowly as they get too hot and can’t cool fast enough. Overvoltage breaks things instantaneously with a “pop” and is unforgiving.
If it wasn’t for the rating on the gate driver, I’d say sure go for 12S or higher if you feel like it but for now we have to deal with that until we start migrating to the DRV8353. Then folks will just want to use 20S instead of 18S…
