Melting connectors

[anon4]

I was using those red plastic bullet connectors for phase and power lines. Yesterday they all decided to melt at once and I was getting some shorts. I have replaced them with the more common kind of bullets seen on ebikes. Is heat in the wires normal or do I need a thicker guage? I extended my motor lead as it was too short with wire off an old motor, they are thinner, could this be the issue?

 

[scott gaza]

Heat to melt plastic is not good news! A wire that is 10 awg is at least 2.2mm thick and a triple cored wire is good for around 30amp. Any less than 2mm - 12awg with more than three cores you will be going in to sub 20amp territory. A 10awg wire 2.6mm thick with more than 24 cores will fall under the 20 amps required.

 

[anon4]

It's only a 20amp controller, but I have soldered the shunt a little, don't think I've added more than a couple amps. The wires themselves are coping fine, just the connectors that are burning out. Could be because the controller is in a box, maybe adding some holes for air to circulate would help? The wires have many strands and are probs about the 2.2mm you quote, would have to measure to be certain. Problems seemed to begin when I changed from 36v to 48v

 

[Andy-Mat]

I was using those red plastic bullet connectors for phase and power lines. Yesterday they all decided to melt at once and I was getting some shorts. I have replaced them with the more common kind of bullets seen on ebikes. Is heat in the wires normal or do I need a thicker guage? I extended my motor lead as it was too short with wire off an old motor, they are thinner, could this be the issue?

I would say definitely.
Always replace with the same or slightly thicker. Though thicker may use up space that you need.....If you are pulling 20 amps, you may need a better connector.
Did you just change the battery? Or did you replace the motor and controller, assuming the controller cannot be programmed for the higher voltage, some actually can.
regards
Andy

 

[vfr400]

Connectors are a weak point on phase wires. Cheap ones usually melt. I'm thinking about why you swapped to a different connector, when you could have just soldered the wires. It's quicker and easier to solder the wires together rather than solder on connectors, and soldered wires give a much better connection. Connectors are for people that can't solder, or for wires that need to be frequently disconnected.

 

[anon4]

Connectors are a weak point on phase wires. Cheap ones usually melt. I'm thinking about why you swapped to a different connector, when you could have just soldered the wires. It's quicker and easier to solder the wires together rather than solder on connectors, and soldered wires give a much better connection. Connectors are for people that can't solder, or for wires that need to be frequently disconnected.

I like connectors, throttles like to break in particular, keeping things modular makes replacement easier. I could probably solder the motor as that's unlikely to go, but I'm planning on swapping to a KT controller soon. Any issues in future I may try your approach

 

[anon4]

I would say definitely.
Always replace with the same or slightly thicker. Though thicker may use up space that you need.....If you are pulling 20 amps, you may need a better connector.
Did you just change the battery? Or did you replace the motor and controller, assuming the controller cannot be programmed for the higher voltage, some actually can.
regards
Andy

Didn't even see your post earlier. Tbh the core isn't actually much thinner come to think of it, the original wires just have more insulation on them. I think those connectors are a bit crap, they didn't fail at 36v but they did shrink shut. The controller I'm using is dual voltage so no problems there

 

[Nealh]

For phase I use MT60's with insulating shrouds, if thinking of using double check how you wire them as it is easy to put the shrouds on incorrectly.