how much wattage can a 200w front hub motor really take?

jimmyhackers

10 kW
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May 11, 2015
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600
friends dad dropped off a powabike....200w brushless front hub wheel bike.

esc is caput...so new one needed.

not really much differenence in price between a 200w esc and upto a 500w one.

so just wondering if anyone has overpowered any tiny front brushless hub motors and where the safe limit is?
 
As long as you are replacing the controller, one option is to raise the voltage 30-50%

If it uses 24V, go to 36V, if it uses 36V, go to 48V

Small motors are heat-limited, so raising the amps can quickly kill it.
 
thanks for info.

it was using a 36v battery but it was broken, so i put a new 48v on it 2 years ago.....it's probably why the esc broke finnally.
im suprised it lasted that long tbh. its the size of a postage stamp :lol:

2 years ago, the motor never even got remotely warm when i tested it, the esc got warmish but not hot.
i used a proper tester today and the motor is fine, but again esc was broken.

so a 250w 48v controller would probably be ok?
 
The limit is heat. The more torque a motor outputs the more amps it uses the more heat it produces.

In other words: torque = amps = heat.

This applies to going fast, but also especially climbing hills. Otherwise there isn't really a power limit, besides how much the gears can handle. So if you really want to push the motor the thing to do is to add some sort of thermal monitoring. People have modified BBQ probes to do this sort of thing. Or you can add a proper thermistor.

Otherwise nobody can really be 100% sure how much the motor can take.

However I would expect that a 250w 48v controller would be fine, provided you are willing to pedal and help out on hills. Just don't try to take steep hills at slow speeds with motor-only. That will toast the little guy quite easily.
 
I'd bank on about 500W to 1kW per kg of actual motor.

If it's geared, estimate the weight of the actual motor, the gears and rest of wheel doesn't count.

Think... Qs205 is about 13kg and takes about 10kW. Mxus 3k will take 7 or so... Weight about 9kg

I have a1500W hub motor that weighs about 7kg for the hub and will take 4 or so...
 
If u knew the magnet temp ability and the wire rating and you had a temp sensor you could get a very good idea of the peak power limit snd how long till the magnet wire insulation breaks down. I’ve put huge amounts of current into tiny skate hubs with 200c rated wire and n48sh magnets and they get way too hot but go.
 
Years ago, there was a guy here who purposely killed a 2 Kg. Q100 (call the Cute back then). He got to 18S (70 some Volts) before the windings melted.
As the Volts go up, the motor wants more Amps to sustain higher rpms which raises the total Watts. Kind of a "no-win".
With a Q100H, I found that 14S (54 V nom.) on 20 Amps was the practical limit. More Volts barely boosted the top speed and more Amps caused the motor to start to hammer.
I ran some hot-rod square-wave controllers on 14S for a while;
With a Lynn Mini Monster (22 Amp max), the frt. mounted Q100H was close to spinning the tire on dry pavement and a Grineon 25 Ammper was too much, it really hammered the motor to the point is was audible.
Never killed a motor, but before I learned to stay away from real hills w/ these high-powered mini set-ups, I would melt the phase wires (which usually killed the controller).
52 Volts on a soft-start sine-wave controller makes for a nice mini-motor set-up that will do low to mid 20's mph while climbing decently (22 mph w/ the 201 motor-speed, 24 mph w/ the 260, both in 26" whl.s)
 
I was throwing around 1600w at a 250w geared hub motor (swxk24) and didn't melt it down. Was originally a 24v Hilltopper kit, which got swapped out with 18s lipo and a Nucular 24f. Was averaging 35mph around town, but I didn't make a habit out of climbing hills. When the going got steep and speed slowed, I hopped off and walked. Swapped that pos out for a leaf motor. Very happy with it.
 
Better ck the way you measure speed. The only way a mini hub motor is going to avg. 35 mph is if the bike is thrown off a cliff.
 
There is a 25 mph speed limit in town with multiple radar based speed indicators. Both the Nucular display and those signs are within a 1 mph difference, for both the other motor and the leaf motor.

Voltage will get it spinning. (It might have been closer to 30mph, it's been a while, but definitely out of the 20's)

To be clear, I don't recommend doing this. I considered the motor largely disposable. Now it awaits my kid growing to the point that he can ride a 20" wheel bike at which point it will have some usefulness to me.
 
ive ran geared hub 36v 250 watt motors a few times one was using two 36v 11ah packs in series,that was on an outrunner type motor,went about half a mile,windings shorted and took out the controller fets,next experiment was a front hub inrunner motor,ran that at 48v with a 350 watt controller,after about 3 miles flat out got a horrid noise from the motor then it jammed solid,turns out it had sentrifuged the magnets out of the rotor!,last one was running 65v on a rear geard motor at 1kw,used to go for about 2 months using on a 3.5 mile trip to work and back,then stripped teeth on the mylon gears,tried to find steel replacements so gave up and got a direct drive motor,good and reliable but weight a ton!
 
never saw the point in geared motors.....my gearless hubs sem just as happy on hill climbs

gears can just brake, wear and sap efficency.

id go brushless gearless all the time.....only thing to need replacing should be bearing eventually.
 
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