Bafang 750w rear hub motor max Power?

[paulstung]

Hi all, I'm looking at a p rebuilt that comes with a 750w rear bafang hub motor I'm not sure if it's direct or geared at the moment Im waiting for a response from the seller, and a 48v 20ah, 50amp battery.

My question is if I was to upgrade the controller and battery what would be the maximum power that it could handle, would I be expecting to much for 60v at 80 to 100 amps? If so how far of the mark am I? Thanks guys..

 

[amberwolf]

Sounds like you need something like the QSmotors QS205 50H or better.

100A at 60v is 6000w, twice what even those are rated for, but they'll probably take it at least in bursts.

Otherwise, you're looking for motorcycle motors and parts, that are meant for that kind of power. Not ebike/bicycle stuff, that isn't.


You're not likely to find a cheap typical ebike motor that will take that kind of power very well, for very long; it might break the first time it's used if it's a geared hubmotor (either breaking the clutch or gears, or just overheating, etc.

Watt ratings of motors don't "mean" much directly, but they can be a good guide to what a motor might handle. If you want a lot of power, you need a motor designed for that, a controller designed for that, and a battery designed for that.

Whatever part(s) you use that aren't designed for that are the weak links in your system; no point in wasting money on stuff that will not do what you want.

Hi all, I'm looking at a p rebuilt that comes with a 750w rear bafang hub motor I'm not sure if it's direct or geared at the moment Im waiting for a response from the seller, and a 48v 20ah, 50amp battery.

My question is if I was to upgrade the controller and battery what would be the maximum power that it could handle, would I be expecting to much for 60v at 80 to 100 amps? If so how far of the mark am I? Thanks guys..

 

[paulstung]

When I had more of a think about it, I'm thinking that 3000w max would be a better fit, so max 50a.

The bike is very similar to a super 73 only longer and more cafe racer inspired. And as far as components I've got plenty from downhill and enduro builds in the past and a new unopened set of magura quad pot mt7's here. I'm pretty confident that they can handle 3000w. With the appropriate controller and battery do you think the Bafang 750w is capable and would a geared vs direct effect the outcome?

 

[999zip999]

1,800 watts safe 2,200w on a hill till it melts
How about a mxus 3,000 72v @ 50amp. With temp gauge in motor and a C.A V3. Go git more money. And a better bike.

 

[E-HP]

My question is if I was to upgrade the controller and battery what would be the maximum power that it could handle, would I be expecting to much for 60v at 80 to 100 amps? If so how far of the mark am I?

Can't answer this question ^^

Until you answer this one:

rear bafang hub motor I'm not sure if it's direct or geared

 

[AHicks]

My question is if I was to upgrade the controller and battery what would be the maximum power that it could handle, would I be expecting to much for 60v at 80 to 100 amps? If so how far of the mark am I?

Can't answer this question ^^

Until you answer this one:

rear bafang hub motor I'm not sure if it's direct or geared

That's an easy one. Bafang doesn't make a DD

As far as putting big power on a geared hub, even a big one, keep in mind that motor is not getting any kind of cooling buried within that housing. If serious enough to try anyway, filling it with oil is a good plan.

 

[amberwolf]

When I had more of a think about it, I'm thinking that 3000w max would be a better fit, so max 50a.

The bike is very similar to a super 73 only longer and more cafe racer inspired. And as far as components I've got plenty from downhill and enduro builds in the past and a new unopened set of magura quad pot mt7's here. I'm pretty confident that they can handle 3000w. With the appropriate controller and battery do you think the Bafang 750w is capable and would a geared vs direct effect the outcome?

of 3000w? ,no.


my previous post already advised what *would* work.

 

[999zip999]

Ok Ok I get it a 750 w motor with plastic gears .
OH OK 1,800 W OK 2,400W ONLY IF I get off my bike and put my hands on the motor. Or melt you Know I get iti think I explained earlier.or just run with it.
Then report back.m Thank you.

 

[paulstung]

Cheers guys, if the seller answered DD or geared it would of cleared it up instantly. NO..

 

[E-HP]

Cheers guys, if the seller answered DD or geared it would of cleared it up instantly. NO..

For a DD, for a short period of time. For geared, it would break.

 

[AHicks]

Cheers guys, if the seller answered DD or geared it would of cleared it up instantly. NO..

For a DD, for a short period of time. For geared, it would break.

Bafang doesn't make a DD

Big power on a geared hub doesn't break, it melts....

 

[E-HP]

Cheers guys, if the seller answered DD or geared it would of cleared it up instantly. NO..

For a DD, for a short period of time. For geared, it would break.

Bafang doesn't make a DD

Big power on a geared hub doesn't break, it melts....

understood, but op said "if". 100A through a geared hub might be a good experiment though to see what fails, but 280NM is a lot for plastic gears. Just below the melting point on flat ground, but add a little 3% grade and it melts, for a G60:
https://ebikes.ca/tools/simulator.html?motor=MG60_750&batt=cust_60_0.05_24&cont=cust_100_250_0.03_V&hp=0&axis=mph&frame=mountain&autothrot=false&throt=100&grade=0
A dd may heat up fast, but no parts to break.

 

[amberwolf]

Big power on a geared hub doesn't break, it melts....

Sometimes it does:
https://endless-sphere.com/forums/viewtopic.php?t=15570&start=300#p550415
The best pic seems to have disappeared, but this one you can just see the cracked clutch held together with the hose clamp so I could get home (the silver crap all over is aluminum ground off teh inside face of the housing by the just-too-wide hose clamp):

(further down that page, Dogman melted SMT parts' solder on the hall board overheating another one of the same motor, one of those....there's some pics if you're curious..but I fixed it enough to work, and sometime before I broke the clutch on the first one I overheated it enough to make the halls temporarily stop working correctly...somehow I never quite got it hot enough to melt the gears :lol: ).