cassschr1 wrote:What is the spacing of the drop-outs 135 or 150?
Alan B wrote:cassschr1 wrote:The swingarm is steel. Bending is possible, not easy though to keep the proper alignment of the dropout.
Alan B wrote:Bad News
Went out for an easy noontime ride around the worksite. Nothing got warm, but on a gentle takeoff from stop the 24 4110 FET controller with stock settings, 62V, about 3000W peak -- shorted.
The motor cogs badly even with no power. Had to unplug the motor from the controller to ride it, and push it back uphill. Seems like shorted FET(s).
Now I'm sweaty.
zombiess wrote:I'm betting the FETs in that controller were not matched. Paralleled FETs that aren't matched for their miller plateau can have very different turn on and off times causing current hogging. That's why I build my own controllers no matter how much I hate doing it. I wouldn't be surprised if my 18 FET 4115 could handle some short bursts of 130A at 125V if it had matched FETs. I'm pretty sure the 36 FET controller I just sold could do some 250A bursts into a small wheel at 125V, but I never got over 120A with it which couldn't even get it warm. I'm trying to build up another 36 FET now and also have a 24 FET I'll probably build with 4110 FETs at some point.
Good luck fixing the controller Allen. They can be a real PITA to work on. I'm desoldering a 36 FET board right now and it's quite a time consuming process.
Since you are taking it apart, you might want to look into my 36FET controller build. I don't know what insulator is used on your controller, it could be kapton with thermal grease or it could be a mystery insulator. I personally like using Wakefield 173-7-220P insulators. I'm also sold on using buss bars to connect the tabs as you've probably seen me post more times than you can count. The devil is in the details with making these things live.
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