View Single Post
Old 03-23-2018, 10:15 AM   #3 (permalink)
Master EcoModder
Join Date: Sep 2010
Location: Saskatoon, canada
Posts: 1,466

ChargE (not yet running) - '92 Mazda MX6 LX
90 day: 33.89 mpg (US)

Ford Prefect - '18 Ford F150 XLT XTR
Thanks: 741
Thanked 538 Times in 433 Posts
Originally Posted by Amateur View Post
And decided that $124 that if it failed I would have a nice enclosure to build one of my own design. remarkably the controller has not failed yet but was never able to blow a 120 amp fuse. "600 amp for 10 seconds"
That motor looks like it is rated for 200A at 96V. Since your e-bike is so light, I think the load is not high enough to draw 120A.

As an example - the stock controller on my Polaris Side-by-side, or UTV, is rated at 650A for 10 seconds and it is moving me, 600 lbs of lead-acid batteries, and 800 lbs of frame, suspension, transmission, and everything else. It only goes 40 kph and it accelerates there in under 10 seconds. The 650A is the output to the motor (at a slowly increasing voltage) not the measured current into the controller from the battery.

I would expect your 120A fuse to be a slow-blow fuse. That is quite typical for Electric Vehicles. So it will not blow if you are drawing 120A. You can typically run at 150A for 120 seconds or more, 200A for 30 seconds ... there is a curve for the fuse where you look up how long it will let you run at what current.

My experience with Kelly controllers is that they work fine as long as you keep them cool. Over-sizing them is one way - they don't heat up much if they will do 600A and you only run 200A. You can also use a fan .. or the wind going by as you drive! I have read about bolting controllers (not just Kelly) to an aluminum heat sink with liquid cooling, like a transmission cooler, for longer distance driving.
In THEORY there is no difference between Theory and Practice
  Reply With Quote