Tesla motor connector showing signs of overheating

[alcatraz]

Hey fellow riders

My Tesla v1 has an odd thing going on. One of the motor cables is looking very toasty at the connector (not at the board but between the board and the motor).

What I find weird is that it's only one of the three cables. I wonder if this is common? The other two look clean and show no symptoms of overheating.

I saw somewhere that if the male connector doesn't provide enough spreading force, it won't make a solid connection and as such it'll overheat. 

I'm thinking about cutting the melted black "clear" tubing off, disconnect it and opening the male connector up some more. Is that a wise thing to do?

I would need to replace the outer casing with something that's very heat resistant. I wonder if you have a suggestion? Is heatshrink enough or is there something special that is ideal for this kind of stuff?

The wheel works fine, and I have the wires spread apart with some zipties. I don't think it'll short out but it looks nasty with the black heat spots. Would you fix it or leave it?

Thank you!

Edit: I found this stuff online. It says it can withstand up to 350C continuously and 1600C momentarily. That's some impressive protection. Is this the stuff I need? It's a bit tricky to keep it in place perhaps. Should I run this along the whole length, one for each cable?

Edited October 14, 2021 by alcatraz

[Tawpie]

If that's fiberglas (I can't tell) sheathing, it will do fine. 1 piece on each wire, you don't want to bundle the heater wires together.

That said, the one wire shouldn't be getting that hot and if you can solve that you probably just need to reapply heat shrink. The fiberglas is extra protection against the wire getting so hot it melts through the heat shrink and the wire insulation. Too hot is bad, if you have good insulation and it doesn't melt through... something else will fail.

Regarding the connector, the objective is to make sure that both sides of the connector are firmly and very securely in contact. It actually might just require disconnecting, cleaning, and reconnecting but here again, the object is a tight fit so if the male side can be (carefully) made a little wider all around, it's worth a try.

If the motor wires are stranded, it's possible one or more of the strands in the cable are broken and that too could lead to overheating. There's no good way to tell if you have broken strands without removing the insulation where it got hot, and even a close visual inspection might not reveal the source of a hot spot. Ideally, you'd replace the 'toasty' section of wire just to be sure.

Edited October 15, 2021 by Tawpie

[alcatraz]

Thanks Tawpie.

What concerns me a bit is that I rarely hear any beeps, and still I'm cooking motor cables. I don't think I'm pushing my wheel really hard but something is producing lots of heat.

I have level 1 and 2 alarms off (I use tiltback). Is that why? The only time I hear beeps is when my battery is low.

Turning off level1 and 2 shouldn't disable the 3/5 beeps, right?

A separate question is about the motor wires coming out of the board. They are bundled and share one fiberglass sleeve. This I find odd. Wouldn't it be better if they each had their own sleeve?

Edited October 16, 2021 by alcatraz

[Tawpie]

Heating in the wires isn't monitored, so there's no way the wheel could know they're getting hot. The other alarms are tied to your speedometer, higher speed does mean you're using more power, but the relationship between power and speed isn't exact. Getting going from a stop takes massive amounts of power and braking pushes a large power pulse into the battery even though you're slowing down. It does sound like a poor connection, I think you're on the right track looking into that aspect.

If I were to guess, they bundle the wires into a single sleeve because fiberglas is sold by length and width, and three pieces cost more than one.

Edited October 16, 2021 by Tawpie

[alcatraz]

Right. Three cost more than one. 

I'm sorry. I didn't mean to imply that the wires are monitored. Just that the wires of riders that constantly hear beeps must look way nastier than mine. You'd think that the 3 beep alarm of 80% output was UNDER the limit of melting wires, but apparently it might not. 

It's only one of the wires so maybe it's just a crappy connection then. The clues kind of point to that, don't they?

If you use fiberglass sleeves, would you bother with the PVC tubing over the connector even? I wonder if I should use both or not.

I really appreciate your time and patience. I know this is an old subject but maybe we can help someone with a more updated solution. Cheers! 

[Tawpie]

6 hours ago, alcatraz said:

You'd think that the 3 beep alarm of 80% output was UNDER the limit of melting wires, but apparently it might not.

You'd think so, right? And it probably is, as long as everything is put together just so and working as intended. This is why I take the time to open my wheels up every now and again to have a look see. I'm not at all gentle with mine and kind of expect that stuff will go south. I'd rather catch it and fix it before I end up on my face—definitely before something is wanting to catch fire!