Super hot phase wires?

ebike11 · Aug 19, 2019

Hi guys
I was wondering..is the cause of super hot phase wires the result of incorrect phase and/or hall wire matching? The bike runs fairly smooth with current wiring combination so i thought i bad it correctly, but after 5 minutes of riding they are super hot so i disconnected the battery. 72V on a QS205. I have a beefy controller as well. Just wondering if that would cause that
Thanks!

dogman dan · Aug 19, 2019

Incorrect phase could be it. At high enough power, it does get hard to tell, since it can run with so much power on two phases.

If that, motor and controller should be kind of hot too.

Or, it could be you are now just pulling a lot through the size wire you have, and especially the connector can be heating up, which sends heat down the wire. Just a motor that is heating fast, also sends heat down the wires.

ebike11 · Aug 19, 2019

dogman dan said:
Incorrect phase could be it. At high enough power, it does get hard to tell, since it can run with so much power on two phases.

If that, motor and controller should be kind of hot too.

Or, it could be you are now just pulling a lot through the size wire you have, and especially the connector can be heating up, which sends heat down the wire. Just a motor that is heating fast, also sends heat down the wires.

Ok i see
Would even the wrong combination of hall wires make the phase wires super hot if the phase wires themselves were correct?

kdog · Aug 20, 2019

Correct, either halls or phases being wrong is going to be rough and hugely inefficient creating the heat. Run through (with wheel off the ground) the entire rpm range, try a quick increase in low rpms. There should be no growling, it should be smooth all the way to top speed. At top rpm it should sing rather than be raspy. False combos are usually noticeable rough. If its not this then, check entire controller settings again.
What controller is it? Does it have auto learn for the phase/hall combo?

dogman dan · Aug 20, 2019

72v 40 amps will make 12g wire noticeably warm, but not super hot.

But if you are pulling more than 40 amps, ( and wrong combo will cause more amps ) then your wires need to get fatter as well.

So the hot wires could be a symptom of both, wrong combo or other problem causing resistance, plus a thin wire.

Look at your plugs, it could be the problem is simply a bad contact there. I've melted plugs enough that now I put two sets on controllers.

ebike11 · Aug 20, 2019

dogman dan said:
72v 40 amps will make 12g wire noticeably warm, but not super hot.

But if you are pulling more than 40 amps, ( and wrong combo will cause more amps ) then your wires need to get fatter as well.

So the hot wires could be a symptom of both, wrong combo or other problem causing resistance, plus a thin wire.

Look at your plugs, it could be the problem is simply a bad contact there. I've melted plugs enough that now I put two sets on controllers.

Hi again
Im thinking its not the wires coz the qs205 are really thick wires with thick connectors. I am running at 80A but i guess ill try different wiring combinations over the weekend. The controller has no self learn option

ebike11 · Aug 20, 2019

kdog said:
Correct, either halls or phases being wrong is going to be rough and hugely inefficient creating the heat. Run through (with wheel off the ground) the entire rpm range, try a quick increase in low rpms. There should be no growling, it should be smooth all the way to top speed. At top rpm it should sing rather than be raspy. False combos are usually noticeable rough. If its not this then, check entire controller settings again.
What controller is it? Does it have auto learn for the phase/hall combo?

Hi there
No it has no auto learn option

Super hot phase wires?

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