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Burned Speed Controller Autopsy

I burned my first speed controller, and I'd like to figure out what went wrong. It was a 36 volt 1000 watt speed controller SPD-361000B. I use lithium battery packs made for cordless tools to generate 36 volts at 9 amp hours. I think the large battery packs can output around 35 amps which is over the maximum current rating for the controller. I had the old controller for about a year and pushed the little SPD-361000B hard. I was carrying an extra heavy load up a steep hill when the controller started to smoke. I already ordered a replacement, 24-36 volt 1000 watt heavy-duty electric scooter speed controller SPD-241000D. The new controller has a maximum current rating of 50 amps, hopefully that will solve my problem. Any feedback would be greatly appreciated.



That type of failure happens when a speed controller is overloaded beyond its capacity. The controller's failure is caused by the load that the motor demanded from the controller, and not by the maximum output current of the battery pack. The SPD-241000D is a much larger and more capable controller with better output transistor cooling so it will help to prevent this type of failure from occurring again. 

Thank you for diagnosing my failed speed controller. I have a new problem with the SPD-241000D speed controllers. I ordered two of the same SPD-241000D speed controllers, but one of the throttles is outputting 10 volts. The other SPD-241000D speed controller throttle is outputting the standard 5 volts. I'm trying to use them together on my all wheel drive trike.

Here is a photo of the controller and my all wheel drive trike.



I just checked with the manufacturer and regardless of the output Voltage going to the throttle, the controller's throttle signal input range will still be 1-4 Volts so if you are wiring one throttle to both of the controllers then you could use the controller with 5V output to provide power to the throttle, and then wire the throttle's ground and signal wires to both of the controllers. 

If you need both controllers to have a 5V throttle output then please submit a support ticket to let customer service know and they will be able to help you with that. 

If you are running each controller off of its own individual battery pack then the negative wires of both battery packs will need to be connected to each other otherwise the throttle may not operate both controllers. 

IT WORKS!!! I connected the throttle ground black wires and signal white/blue wires together on all three controllers. Then I connected the controller with 10V output to provide power to the throttle red wires. The throttle output range is still between 1-4 volts. I am running all three controllers with there own individual battery pack and all of the negative black wires are connected to each other. Thanks again for awesome tech support.

You are welcome and thank you for sharing the great news.

I took the new controllers for a test ride, and I'm amazed at how powerful the heavy duty SPD-241000D speed controllers are. I did not change the motors or gearing so the top speed is the same 30MPH, but the new controllers accelerate at a much faster rate. I also upgraded all of the thick battery wires to 10 gauge with 45 Amp Anderson Powerpole connectors. One last improvement I made to the stopping power is a 200mm disc brake rotor normally used on downhill mountain bikes.


That is great to hear. The SPD-241000D controllers are in whole different class than the SPD-241000B controllers in regards to the amount of power that they output to the motor so we are not surprised that the acceleration is a lot better now. We just added Anderson Powerpole connectors to our site this week so it is very serendipitous that you mentioned them. Wow, I did not even know they made a 200mm disc brake rotors for bicycles, I have seen 160mm and 180mm before but not 200mm. That is great to know that such a big brake rotor is available. 

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