I just received my second Hua Tong 72V 1500W controller. I installed the stock controller in my Tunigy 80-100 build and here are my results/observations:
The controller pcb revision C-D3.2 and is labeled as 38A +/- 2A instead of 40A +/-2A as my first one. Another difference is that this one has IRFB4310 FET's instead of IRFB4710's. According to the spec sheet the IRFB4310 is a better part with 5.6mOhm resistance instead of 14mOhm for the 4710. It's also rated at 140A instead of 75A however this is inconsequential as both parts are package limited to 75A. There are a few extra wires coming out, one of which is orange and has no connector.
The controller works perfectly under no load conditions - nice throttle response. However under load with about half throttle, the controller cuts-out badly. I'm not sure if the controller is reaching its current limit and then backing off, back on, etc., or if it's a timing issue that is exacerbated under load. It's possible however to exceed this limit where the power oscillations fade and the controller seems to do fine again. If you watch the video you can see when I cross over the cut-out threshold and am able to apply full power under WOT. The controller is capable of doing over 1500W continuous with very little warming of the case.
I like this controller as it is smaller than the Kelly I have and fits nicely into the box with my batteries. If I could figure out why it's so jerky in that mid-power band it would be a viable candidate for this bike. I will do a bit more testing in the stock configuration and then I'll mod the shunts with a bit more solder to see if this takes care of the cutting-out behavior or perhaps lets the smoke out.
I also tried to get the controller working in sensorless mode, as others have suggested is possible, to no avail.
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