36V 350W front hub motor

[Kelono]

I’ve googled and searched but to no avail. I can’t find a 36V 350W front hub motor. Seems like it would be a simple thing to find but no! Anyone have a source for this type of thing? Bonus points if the power is coming out on the left side (same side as the disc brake).
Thanks!!

 

[Chalo]

Motors don't have a wattage. That part is up to the controller.

 

[Kelono]

Great! So why does the hub I have installed in my bike have 350W stamped on it? Is it the max capacity or something else? Can I use a hub with 250W stamped on it and expect the same performance? Thanks for the help!!

 

[calab]

This explains it very well.

Click on LEARN then click on HUB MOTOR POWER RATINGS

Futility of Motor Power Ratings

"There's no such thing as a rated watt!" Read here for why we don't advertise a simple power rating for the motors we sell. Also, have a look at our Youtube video where Justin talks about the power to propel bicycles in <a href="https://www.youtube.com/watch?v=ALde6zhLPs0">"School of Watts"</a>.

ebikes.ca

" The reason we don't have a simple power level for each motor or kit is that there is no standard or even consistent way to provide a numeric "watts rating" for a motor system. You can see the exact same motor listed as 250 watts, 500 watts, and 1000 watts by different vendors, and there is a valid justification for all those number. That makes a vendor or manufacturer's watts rating in isolation a fairly pointless figure for choosing or comparing setups, and we're not keen to particiate in that kind of arbitrary numbers game. "

 

[neptronix]

There's plenty of 350w front hub motors out there. Most of them are Chinese.
You could use a 500w motor with a lesser controller and get 350w out of it.

A rear motor is typically better, and more common these days.

 

[rafalg]

Two years ago i got an used front wheel with 250W Bafang motor in it (at least the motor symbol included '250'). Attached it to a bit more powerful controller, like 350W as i remember, and it goes without any problems. Decently powerful and doesn't heat up at all. The whole thing cost me around 45EUR so its really cheap upgrade. And i dont see any disadvantage vs rear wheel - with such kind of power it just works OK, no matter which wheel has the motor. Front drive helps a lot when going thru sand pits - push the throttle and the front wheel will pull you out from any amount of sand (two wheel drive when you pedal too).

 

[2old]

For one, DillengerUS has a 350w. This was my first kit and it's still running on my daughter's cruiser 10 years later.

 

[alan0048]

Motors don't have a wattage. That part is up to the controller.

I know you're talking about semantics but you're still wrong They do have a Wattage (max), the definition is not just about producing (controller) it's also by consuming.

As Wattage is the amount of electrical power expressed in Watts (J/s) the definition includes 2 cases.

1. power, esp electric power, measured in watts
2. the power rating, measured in watts, of an electrical appliance

As for the OP. Wattage is the most important thing for a motorhub, all there is too it are copper windings. You can power a 36V 350W hub with a 48V 7A controller and all will be fine.

 

[Chalo]

I know you're talking about semantics but you're still wrong They do have a Wattage (max), the definition is not just about producing (controller) it's also by consuming.

Sure, but it's approximately 100% incorrect. Anyone here who's tried some things knows that hub motors are notoriously underrated, and inexpensive batteries are notoriously overrated.

At best, I think you could correctly say that the motor's rating is somewhat likely to be proportional to the motor's actual power handling capacity. Proportional, but inaccurate.

 

[neptronix]

As for the OP. Wattage is the most important thing for a motorhub, all there is too it are copper windings. You can power a 36V 350W hub with a 48V 7A controller and all will be fine.

That's not true, the additional voltage will increase the speed of the motor and also the amperage it will want to pull, so we can't just willy nilly chose any volts/amps combination and expect it to just work out.

I always advise people to play with the ebikes.ca motor simulator to see how a given motor would perform on whatever combination of max controller amperage, battery voltage, and winding. The results of this simulator are known to be very accurate.

Anyway you could run a higher than usual turn count of 500W motor or run it on wimpy voltage to get an equivalent of 350W nominal.

 

[neptronix]

OP would probably be happy with this motor:
Bafang G311 Standard Wind

Only 4.9lbs and has the potential to push more power than he's looking for if he catches the speed bug ( most of us will )

 

[neptronix]

Would you look at that, pulls 344w on 36v in a 700c wheel.

 

[alan0048]

Sure, but it's approximately 100% incorrect. Anyone here who's tried some things knows that hub motors are notoriously underrated, and inexpensive batteries are notoriously overrated.

At best, I think you could correctly say that the motor's rating is somewhat likely to be proportional to the motor's actual power handling capacity. Proportional, but inaccurate.

Sure it's approximation, and a motor is typically built for much more than it's rated Wattage to make up for a number of efficiency losses. But to flat out claim "motors does not have Wattage" is 100% wrong from a physics point of view which holds truest as the power of an electric motor is expressed in watts (W). Again, Wattage includes both ratings and a generator's output.

Like if you wanna go down the word mumbo jumbo rabbit hole you can make the same argument to just about everything that has some form of temperature dependency which also includes bandwith / frequency. That's more or less electrical engineering 101, theory and practice don't always go hand in hand but you can't argue against the very definition

 

[alan0048]

Well I was thinking 48V 7A = 336W in theory, meaning a 7A current limitation on the controller would get you close to 350W and it would work equally good. Was just an example ^^

Would you look at that, pulls 344w on 36v in a 700c wheel.

View attachment 352055

Yup that would probably be a good choice if nothing else.

 

[neptronix]

A motor's rating is more based around @ what power level does it maintain natural thermal stasis ( doesn't overheat ) for a very long period of time.

This is why geared motors in particular have such low continuous watt ratings despite the massive amount of power they can take and turn into useful power. Their ability to shed heat ( which is poor ) determines their continuous rating.

The fun part of geared motors is that you can push them extremely hard for short periods of time.

 

[alan0048]

A motor's rating is more based around @ what power level does it maintain natural thermal stasis ( doesn't overheat ) for a very long period of time.

This is why geared motors in particular have such low continuous watt ratings despite the massive amount of power they can take and turn into useful power. Their ability to shed heat ( which is poor ) determines their continuous rating.

Sure, that's exactly why I agreed with it's an approximation. But a 48V 7.29A will produce as much heat as a 36V 9.72A, as it's equal amount of energy being delivered. But you'd have to current limit that shit for it to work in real life as it was more an answer in theory

Naturally that's done with every motor, you'd have to take a number of efficiency losses into account but you'll end up with a baseline for which the company agrees this a "good" value where they can with certainty say it should be capable of delivering for continuous duty.

 

[neptronix]

No, it doesn't work that way, you have to take into account the motor's design, efficiency curve, turn count, wheel size, etc, you're ignoring a ton of factors that can swing the amount of heat a lot.

Even more complicated, from one turn count to another, they will use thicker or narrower gauge wiring, so you change the turn count and one motor overheats at 15 amps but the other 45..

Please play with the ebikes.ca simulator and see. It's just not that simple as X watts = X heat.

 

[alan0048]

No, it doesn't work that way, you have to take into account the motor's design, efficiency curve, turn count, wheel size, etc, you're ignoring a ton of factors that can swing the amount of heat a lot.

Even more complicated, from one turn count to another, they will use thicker or narrower gauge wiring, so you change the turn count and one motor overheats at 15 amps but the other 45..

Please play with the ebikes.ca simulator and see. It's just not that simple as X watts = X heat.

Yes it works but It was never intended to be a practical answer. The motor hub only cares about Wattage that's whats going to be overheating your system and burning your copper windings.

overheats at 15 amps but the other 45

36*9.72 = 48*7.29 = 350 (W), if you had a perfect 48V controller able to deliver 7.29A and nothing more it would work just fine instead of a 36V 350W. I never said anything about using a 48V controller being able to draw more with my example x)

But he absolutley could go with a 48V 250W motor controller for any 36V 350W motor if he already was on a 48V system. Without a doubt the motor hub could manage that, regardless if the torque is going to be demanding more there is enough playground to go around with those margins. You wouldnt necessaryily need to go deep into the specs for that it's a no-brainer.

 

[Chalo]

Sure it's approximation, and a motor is typically built for much more than it's rated Wattage to make up for a number of efficiency losses. But to flat out claim "motors does not have Wattage" is 100% wrong from a physics point of view which holds truest as the power of an electric motor is expressed in watts (W).

Well in the real world, I routinely run "250W" hubs at 1000W, and my usual "1200W" hub at 2500W, and neither kind gets more than slightly warm. So I hope you'll forgive my skepticism about motor ratings.

I suppose if you bog your motors down at sub 30% of their free speed all the time, then maybe the label rating might be more or less true. But that would be rating operator incompetence rather than the motor.

 

[lnanek]

Yeah, I tend to run as 750W geared motor at 1800W most of the time and no issues at all either. Replaced OEM controller with one with more max amps and done.

Changing voltage is a much bigger deal than changing amperage, though. Every motor has a KV rating that determines the max rpm for a given voltage without field weakening (determined by things like the number of turns in the windings). My motor maxes out at 30mph at 48V and I can get a few more mph from field weakening. 36V would be completely useless for me. No matter how many more amps you pump in, the top speed would still be more limited.

Going from 36V to 48V would be good for top speed, bad for torque. That could put you into a situation where you overheat trying to go uphill or not. You can use the motor simulator to find out.