Charging cable warm to the touch... normal?

Charging cable warm to the touch... normal?

When I'm recharging using my NEMA 15-50 circuit, the cable feels warm to the touch. Not burn your hand hot, but pleasantly warm to the touch.

Is this normal? Anyone else notice this?

mrspaghetti | December 10, 2012

Sounds normal. 40 amps is a lot of current, it's bound to get warm.

Captain_Zap | December 10, 2012


Jolinar | December 10, 2012

Sounds fine, but make sure you are not using extension cords, or at least not roll/reel in/tangle (I am not confident about my English right now) that extension cord... That could be dangerous if heat can't escape.

kent | December 10, 2012

Normal for mine. Not hot, but warm to the touch near the end especially.

Brian H | December 10, 2012

No way! They must've forgotten to use the superconducting wire.


dborn | December 10, 2012

BrianH- cant get the wire to zero kelvin yet!

Mark2131@CA-US | December 10, 2012

Thanks for the reassurance! No extension cords. THe outlet is just two feet from the charging port!


Brian H | December 10, 2012

High-temperature superconductors are (always) just around the corner ...

cosmomusic | December 10, 2012

I call TM to inquire about the same thing. They assured me the warmth felt while charging is normal and that the connector is not at risk of breaking down.I was initially concerned that there could be thermal runway occurring in the control box.

jat | December 10, 2012

As long as you can hold it indefinitely, you are fine. Most recent wiring is rated for 90 degC, which even through insulation you wouldn't be able to hold for long. Older wiring has insulation is only rated for 60 degC, but even that will be too hot to hold.

phb | December 10, 2012

Yep, it's totally normal. That's a lot of current. It's too bad though, doesn't the heat mean lost efficiency?

jat | December 10, 2012

@phb - yes, but the only thing you can do about it is send the same amount of power at higher voltage and lower current to minimize losses due to resistance (which is why power distribution lines run at very high voltage).

I don't know how much of it is in wiring vs charger vs batteries, but the typical charging efficiency is a bit under 90%.