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[ElectricCafe]

Hello all,

I am a Sr. Mech. Eng. student converting a dilapidated Honda 250 Nighthawk to an electric drive. My team and I are planning on running a 48V, 40Ah pack. Depending on budget we will be running Thundersky Li-ion or Standard deep cycle SLA batteries. We're set on the EMC-R Motor (48V, brushed DC) along with one of the Alltrax controllers.

I have done my due diligence on trying to understand the logistics behind choosing a controller but am having issues. I assume that larger amperage controllers are suited to higher voltage and amperage applications - But why? We were planning on using the least expensive option (Alltrax 48V, 300A) simply because of budget. I would really like their to be some better logic behind the decision. Also, what role do Li-ion vs SLA play in choosing a controller. I really need this spelled out for me. Thanks

Motor Specs:
Power: 8 cont-- 15 pk hp
Voltage: 48 Volt rated
Speed: 3700 rpm @ 48V unloaded (72 rpm per volt)

[frodus]

higher voltage is more efficient, you can use smaller cables, and you can produce more HP with that Etek.

voltage equates to RPM.
Current equates to torque.

Higher Voltage controller, Higher RPM. Higher RPM, and you might get more HP out of the motor.
Higher current controller, higher torque. Higher torque also gets you higher HP.


SLA and Lifepo4 don't really matter for controllers that are programmable (Like the Alltrax AXE controllers, Kelly controllers, Sevcon). If its like some of the other Alltrax, or one of the curtis controllers, you may have trouble, I don't know, you'll need to research that.

Lead is cheap and easy but you might not get the range you want for the weight. Lifepo4 is more expensive but allows you to lighten things up a bit and thus get more range for the same amount of energy.

[ElectricCafe]

Frodus,

Thanks for spelling it out. I was on that path but wasn't making the connection.