I have one of these bikes which I bough as scrap. I’ve fixed the battery and am sourcing a new front end for it as it was crashed.
I want to put VESC on it and I am curious as to how much wattage the motor can handle. Its made as a 250w bike but has a cable you can disconnect to remove the speed limit which will get you to 20mph. The motor is large and looks bigger than the average 250w motor, the bike takes off with what feels like more than 250w. I was thinking of trying 500w and seeing how it goes.
Anyone know of a good way to get a rating for the motor? I could potentially disassemble to motor and look at the size of the windings and magnets. If I watched the temperatre while varying the power whilst riding it and try to stay under 80 degrees celcius would that be the best bet?
Cheers,
Moja.
Sounds like a plan to me. You could also look into adding statorade and thermal epoxy some heatsinks to the hub itself, statorade was made exactly for this. They also make round aluminum heatsinks to add to hubs.
What’s the S count on the battery here? Are you trying to keep the same battery? 20mph not limited sounds slow, you could try going higher voltage, go faster and have the sameish heat for more power.
250w is supposed to go 15mph topspeed. So I think it’s simply advertised as a 250w motor for legal reasons and that’s why theres a physical limiter. 20mph means it’s in reality a 500w motor. You sadly won’t be getting much more out of it. Giving it more power will increase it by about 2 or 3 mph before you see the temps skyrocket. You’re way better off spending a bit of money on a new motor with a higher rating. Just make sure you’ve got the right measurements or its gonna be a bitch to fit (took me 6hrs to fit mine due to a misunderstanding with the seller)
Start at something like 500W and run it through its paces. Monitor the motor temperature while doing so.
If it stays cool, up the power.
If it doesn’t stay cool, don’t up the power.
Motors (depending on the type) can usually handle being pushed quite a bit past their nameplate ratings as long as proper cooling is provided.
Unless you actually saturate the core, there’s no real hard limit to power in an electric motor. More power makes more heat and you’ve got to get rid of that heat, obviously. But if you improve the cooling, you can improve the power, on and on until you hit the magnetic saturation limit.
I didn’t use the correct terms. My bad. But I’m also speaking from actual experience with my ebike. My 500w motor reached a wall at a point. I tried giving more voltage and upped the amps. It gave 3.1mph extra. Tried going up just a little more and motor would get hot in under a minute and throw me so many temp warnings on my phone. I’m not sure how to explain this other than all that had changed is that I gave it “more power”
There’s a good chance of that. But it’s still 100% functional. Bench test with the original controller worked fine
I’m just happy I didn’t saturate long enough to cause permanent damage to it
Saturation is a transient effect, not permanent. As long as you don’t overheat the magnets or burn your insulation, a motor can fully recover from being saturated.
Magnets usually start to give around 80C (depending on the grade).
The enamel on the windings is usually good to 120C+, sometimes up to 180C.
Basically a rule of thumb with saturation testing is, if for example you add 10% more current and you get close to 10% more torque, you’re fine. But of you add 10% more current and get like, NOTHING extra for it, roll it back you’re saturated.
And that’s usually measured from the windings, not the magnets.
On outrunner (hub, esk8, DD, most of the motors we use basically) motors the magnets are outside the stator and have better cooling than the stator. Which is good, because the magnets need to stay cooler.
Im new here and I also have the same bike, I have the latest version3 does this still work? I cant find the white cable please help is the controller on the handlebar or in the lower part near the footwell? Thank you all in advanced
please help 
is the controller on the handlebar or in the lower part near the footwell? Thank you all in advanced