Hub motor internal temperature protection

[John in CR]

I'm in a different situation with unknown temp sensors already in the motor with wiring for the sensor coming out with the wiring harness. I need to figure out how to take advantage of it.

Aren't those scooter motors the gift that keeps on giving
How many wires come off the temp sensor ? If they're a simple 2 wire thermistor you can connect a multimeter across the wires and see how the resistance varies and then use that to run a temp gauge circuit (or at the simplest learn what the resistance is when it's really hot and simply watch for that on the multimeter)

The Fedex man dropped off a couple of more in the afternoon, so now I'm comfortable in hacking one up to see how light and compact it can be as a mid-drive. They're the quietest hubbies I've had, I guess due to almost no extra air space in there and small diameter. High efficiency, effective mountain climbing switch, compact, silent, only a 3:2 gear reduction needed for 50mph with a 26" wheel makes mid-drive regen a reality with no need for an $80 freewheel.

You're right though, riding slowly is better for cooling (especially with a drilled motor). On one one my bikes that does have an internal temp probe I notied the temp jumps a good 5 degrees when I get home and stop (on a hot day I threw a wet towel on it to cool it down and it sizzled and steamed!)

.

I don't have enough controller to get the ventilated motor hot, 10ga phase wires have become our choke point. Here's the hill profile of my son's favorite ride. He weighs 80lbs less and his bike 30lbs less, so our old reliable emoto hubbies work for him. My cargo bike wasn't happy at all hauling me up, but the new motor doesn't even blink switching to low speed for the steepest stuff. There's a pretty good curve at the 2km point, so it's hard to carry much speed attacking that steepest stretch at the 2.1km point that approaches 30% grade which eases up to only 14% for over 500m. It a real hubmotor test that few would pass and almost none that can both make the climb and do over 50mph in wheel.

Waterfall ride hill profile.JPG (20.3 KiB) Viewed 433 times

[John in CR]

I'm in a different situation with unknown temp sensors already in the motor with wiring for the sensor coming out with the wiring harness. I need to figure out how to take advantage of it.

Aren't those scooter motors the gift that keeps on giving
How many wires come off the temp sensor ? If they're a simple 2 wire thermistor you can connect a multimeter across the wires and see how the resistance varies and then use that to run a temp gauge circuit (or at the simplest learn what the resistance is when it's really hot and simply watch for that on the multimeter)

The Fedex man dropped off a couple of more in the afternoon, so now I'm comfortable in hacking one up to see how light and compact it can be as a mid-drive. They're the quietest hubbies I've had, I guess due to almost no extra air space in there and small diameter. High efficiency, effective mountain climbing switch, compact, silent, only a 3:2 gear reduction needed for 50mph with a 26" wheel makes mid-drive regen a reality with no need for an $80 freewheel.

You're right though, riding slowly is better for cooling (especially with a drilled motor). On one one my bikes that does have an internal temp probe I notied the temp jumps a good 5 degrees when I get home and stop (on a hot day I threw a wet towel on it to cool it down and it sizzled and steamed!)

.

I don't have enough controller to get the ventilated motor hot, 10ga phase wires have become our choke point. Here's the hill profile of my son's favorite ride. He weighs 80lbs less and his bike 30lbs less, so our old reliable emoto hubbies work for him. My cargo bike wasn't happy at all hauling me up, but the new motor doesn't even blink switching to low speed for the steepest stuff. There's a pretty good curve at the 2km point, so it's hard to carry much speed attacking that steepest stretch at the 2.1km point that approaches 30% grade which eases up to only 14% for over 500m. It a real hubmotor test that few would pass and almost none that can both make the climb and do over 50mph in wheel.

That last few hundred meters to the top is on foot btw.

Waterfall ride hill profile.JPG

[NickW]

Look at the manual for the CA. you can use the Vi pin on the CA pcb to do on the fly current limiting.

it talks about using a pot, but it shouldn't be too tough to rig something up to work with some resistors and your thermistor.

That won't screw with your speedometer or watt meters.

-Nick