E Moto Build 96v

[nakedsushii]

Planning a build consisting of a mid drive motor.
I’m going with 96v 30ah. Just need help and insight on parts.

What motor should i go with? I wanna go belt drive.
What controller would be paired with the motor?
I’m shooting for 90+mph.
If not mid drive is my only option HUB motor for speed and power?

 

[Chalo]

96V x 30Ah = 2880Wh. By my calculation, 90 mph will require about 30kW at the wheel (so best case, maybe 40kW from the battery) depending on a bunch of factors. To do that, the battery must deliver power at a 14C rate (about 4 minutes full to empty) without the voltage sagging significantly. What cells do you plan to use, and can they do that?

30kW will take a big motor, or a less big motor running at a squillion RPM. What motor were you considering, and can it make at least that much output?

 

[nakedsushii]

Hmm i see. I’ve seen 2 builds using hub motors doing 100+ @96v. i was thinking 21700 molicel.

 

[Chalo]

Hmm i see. I’ve seen 2 builds using hub motors doing 100+ @96v. i was thinking 21700 molicel.

That 4Ah cell is rated to discharge at 45A, which is very impressive.

40kW / 96V = 417A discharge.

417A / 45A = 9.26 cells in parallel at their maximum rating. So let's say minimum 10P. 96V is what, 27 cells in series? So you need at minimum a 270 cell pack whose cell interconnects can each carry 45A of current. That's not easy.

The cells weigh 70g each. So that's 19kg of cells, about 42 lbs, plus however much copper, BMS, and enclosure they need. Maybe 60 lbs total if you're resourceful? Heavy but doable.

Thing is, if you're asking the cells to deliver their absolute maximum rated current, not only is that rough on them, but their discharge voltage will sag a bunch, and then the power won't add up to 40kW. So you'll need some extra cells to share the load if you really want 40kW. 27S 12P pack? 324 cells, maybe 70 lbs all joined up and packaged. Maybe that would do it and maybe not.

Still you have like maybe 5 minutes of run time from completely full to completely empty, at the required power level to reach 90 mph. Is this for drag racing?

 

[nakedsushii]

Not drag racing. Just all around riding the city and some crazy pulls. maybe more ah for range? weight isn’t a problem. id build a 80lb battery if i need.