Hub motor temp sensor?

[LI-ghtcycle]

So I tried my best to find the post, I know I read one that talked about putting a temp sensor on a hub motor to keep from over-heating when climbing hills/over-volting, but I can't seem to find it.

Any suggestions on what type of meters to use, how much they might cost, I'm looking for the most compact unit I can find, show us what you're using.

 

[dogman dan]

I'm using the ten buck, Bell automotive indoor outdoor thermometer. Find it by the air fresheners and other car junk at the big box store, or a car parts place. I like to carefully snip away the plasic sensor housing, so the tiny epoxy coated sensor can get good contact with the metal I want to know the temp of.

Idealy you get the sensor from it into the hub, but for most halls using motors getting two more wires down that axle is easier said than done. If you can do that, you get actual temps up to 160 F, and then it just says overtemp. You should be stopping by 180, but stopping or at least slowing down when you see 160 is not so bad an idea. After awhile, you get an idea where you stand on riding past the overtemp by how fast it cools back down. Using an infared thermometer on the hub has told me that in most weather, up to 100F, I can keep riding on the flat without getting past 170-180.

The other, easier option is to stick the sensor to the axle stub, with enough tape or whatever on it to keep windchill from causing fluctuating readings. Then you take the temp on the readout, and add 30-40F to that. In cold weather, the hub cools better so it may be 30 F hotter. In summer, the heat stays in the hub longer, so the temps tend to run about 40F hotter. So using the external sensor, look to keep the motor under 140F.

The reason to put the sensor on the axle stub is because it doesn't rotate, and it gives a more accurate indication of internal temps of the rotor than the covers, especially with a gearmotor. A small infared thermometer works great too, but you have to stop to use it. I learned a lot about how to ride cooler by having a continuous dashboard readout. Amazing how different styles of riding up a hill affect the motor heating.

If you are worried about controller temps, the same rig could be used to monitor that.

 

[Lock]

I'm lookin to slap these on my LiFePO4 cells (see-thru batt case):

Most of these are made for higher temp ranges... They're too long to fit on 10Ah cells but I'm guessing they can be cut in half and still work fine. Perhaps these sorts of temp strips could serve slapped on a hub motor casing as well
Cheers
Lock

 

[LI-ghtcycle]

Good info thanks!

I was actually wondering if anyone had been able to use a wireless sensor, but maybe I'm not knowledgeable enough to realize the impracticalities of such a set-up? I hadn't considered wind chill, and I really am not sure if I want to split the case on my geared hub motor, but if it's not too difficult, or too tight a squeeze, it makes sense to have the sensor inside.

I like the simplicity of the temp strip, but I'd really like to have a meter on my dash, but that is a good idea to use until I can get one, thanks!