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50 Ah  - exactly. Unfortunately I had to go with a 44 Ah pack due to the 50's being on back order until December. I bought a Bear unit that is quoted on the Trombetta site as being capable of 225-300 Amps continuous with a 600 Amp peak. Thanks so much for the detailed explanation! - I wasn't aware of the change in voltage from one side to the other. This explains my confusion after seeing bikes more powerful bikes than mine with similar contactors.

Need some tech wisdom bestowed on me:
I am planning on using an etek-r motor, an alltrax 650 amp controller, and an agm sla battery pack worth 48Volts at 50Amps. My question is what contactor to use? I want to use the albright 180-SL from Electric Motorsport, but it can only pull 200 continuous amps. Isn't this chump change compared to what my controller is capable of pulling from the pack? Will this contactor cause a bottleneck in my system between the pack and controller? (please be thorough) Thanks all-knowing EV guys!

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)