Newbie builder, thoughts on my numbers please!?

Hi guys,

Sorry if this is a dumb new topic and admin feel free to delete or let me know where to post please.

About to build my first board and have the below numbers, single motor drive and I only weight 154lbs (70kg)

Questions: Do you think 70% efficiency is realistic to acheive? Any idea on climbing ability of this setup given my weight, 20%, 30% incline?


There are other calculators if you search this forum. I usually use 85% efficiency but honestly I don’t know.


I don’t think you’ll do well on hills, but there are other factors like Battery Ampage if its low you will get voltage sag uphill making things worse.

Ok thanks what would you suggest for a battery for the above setup, given I want to get up to 18-20mph and ideally 20mile range? If there are battery Builders on here that sell there services could you tag them please, cheers

Well, What speed controller will you use?

I don’t think it’s a very good idea to use a 270kv motor with a 10s battery. You will be loosing out on potential torque, and you wouldn’t be able to go much faster.

Try to find a 200kv motor, and change your gear ration to 16/36

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Erpm is over 60,000 too. Anything over 60k Can lead to a Faulty ride or worse a blown DRV chip Very possible with a cheap vesc

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Hi im using this one

That esc is bad news dude, People say it heats up etc Your top speed with be also lower because of that esc.

Ok what about matching a better battery to the 270kv Motor, can you suggest one. Does a lower Kv = more torque? Thanks

Its rated to 8000rpm but that might be optimistic :grimacing:. Vesc time?

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Vesc is a good option also you will need a remote here is a good cheap option,

Do you already have that motor? If yes, then 7s or 8s battery would be better. But a 10s system would be more efficient.

Thanks @Blitz , a few questions

  1. what’s the basic equation to calculate Erpm

  2. What does the Charge per cell number refer to on ? Batt is a Li-on 10S 36V?


The speed calculator you used shows it. Read through the centre of the page. Or if you’re using the black more complicated one it’s in the top right corner. But here is the basic calculation eRPM = pole pairs * RPM, eRPM = 7 x 9720 = 68040

normally you can Charge 1c of your battery meaning if you got 3000mah 3Ah You can charge at 3Amps Its just so they can calculate your charge time for you.

if you have any more questions feel free to ask.

Attempting my first build only part ordered so far is the focbox unity. I think I read somewhere…I should buy the battery first then build around the battery. Thoughts anyone? Please do your own research also there’s a dedicated thread for those questions: