What's more efficient?

ESK8 Electronics
#1

So I’m wondering - with the exact same batteries, I can set them up 8s or 12s is there an advantage to either?

342_778_544.png717×422 36 KB
Setup - 2xVesc 2x190kv6355 lipo 20c batteries.
Identical setup on the same board
Watt hours are the same for 12s or 8s. LIMITING THE SPEED to 22mph, what is the better way to go, and why?
Considering - Range Battery heat Motor heat Vesc components

#2

Typically the Higher the Voltage the better, Keeps components cooler, Yet Despite this Esk8 in terms of being efficient is more a matter of Mechanical efficiently , The setup will essentially be the same, because in the end the same amount oh WH is being used no matter 8s or 12s, You wont see the benefits of 12s Speed so you might as well use a 8s to preserve cell life by lowering the amount of Amperage stress on individual batteries.

#3

If you want to reach the same speed with both battery setups the 12S would be more efficient because could use a 33% lower gearing compared to the 8S. But i guess your gearing would be the same in both cases so you can reach a 50% higher top speed with the 12S.

With the same gearing the 12S would be still a bit more efficient because of the lower amps and that means less heat losses but only between the battery and the VESC. I guess in real life you wont feel that difference.

#4

given two identical hub motors except one wound to 50kv and the other 100kv, would there be a decrease in efficiency running the higher kv compared to the lower kv at slow speeds? it seems like with pwm the motor can get any mix of amperage it needs and they would be similar, no? i mean in the motor efficiency mainly but also the esc

#5

I have a 12s 5200mah and a 8s 10ah battery. I’ve used both with a single 190 6355 (among others). Since you only want 22mph. I say 8s.

The real world efficiency gains are pretty small. with 8s its a bit simpler to wire and keep slim. and you can use an 8s balance charger.

Then, if you decide you want more speed one day. just swap in a 10 or 12s battery. No need to change anything else :sunglasses:

also is that range you calculated? seems a bit high

#6

Yes, it was range, but just estimated at 10wh/mi. Also I used max voltage, instead of nominal. But was really just looking at WattHours.

Thanks peeps. I was just seeing if I should to rewire to 12s.

Conclusion - not really necessary unless for top speed increase. :sunglasses:

#7

It’s 10 Wh a km. So it would be 16 Wh a mile. But that is really for a chilled cruise, but possible.

#8

thats what I meant :confounded: And that’s what the spreadsheet cutout is calculated to.