Grin does it again. Regen 36v hub motor 28mph

[tomjasz]

Amazing motor. Built in torque arm, regen braking, 28mph, neat clean wiring, and all the advantages of the proven MAC gearing. Just when I already am 3 projects behind I have to droll over this.

I’ve learned that my beloved mid drives and their complexities have a solid competitor.

At the top of my to order list is the solid 25mph GMAC with a 10s, 36v, Battery. A 35E cell 17ah pack adds parallel cells instead of more in series and offers great mileage. While everyone around me is dumping more amps in search of higher speeds I’m excited about decent speeds and better efficiency. That and supporting mid drives, I have 4, gets tiring compared to care and feeding of hub drives.
https://www.ebikes.ca/product-info/gmac.html

Having a bike builder adopt this system would excite me. But the wiring scheme of this motor is quite well designed and could be a DIY that doesn’t look like an advertisement for zip tie makers.

 

[GregGritton]

It also looks like they have managed to invent a perpetual motion machine A quote from: https://www.ebikes.ca/product-info/gmac.html

"However, even if you are pedaling the bike without assist, the energy that is expended overcoming this rolling drag in most cases much less than the energy recaptured from regenerative braking. This point is really interesting, since it means that the motor could be run all the time at low powers to overcome the rolling drag using just the energy captured from regen, and still put more energy back than expended "

 

[vincent]

Very cool!

 

[Ravi Kempaiah]

Amazing motor. Built in torque arm, regen braking, 28mph, neat clean wiring, and all the advantages of the proven MAC gearing. Just when I already am 3 projects behind I have to droll over this.

I’ve learned that my beloved mid drives and their complexities have a solid competitor.

At the top of my to order list is the solid 25mph GMAC with a 10s, 36v, Battery. A 35E cell 17ah pack adds parallel cells instead of more in series and offers great mileage. While everyone around me is dumping more amps in search of higher speeds I’m excited about decent speeds and better efficiency. That and supporting mid drives, I have 4, gets tiring compared to care and feeding of hub drives.
https://www.ebikes.ca/product-info/gmac.html

Having a bike builder adopt this system would excite me. But the wiring scheme of this motor is quite well designed and could be a DIY that doesn’t look like an advertisement for zip tie makers.

Very clever piece of engineering!

 

[pnop]

Pretty cool but at 4.5 times what I paid for mine, I guess I will stick with what I have. 23-24 mph is fast enough for me.

 

[tomjasz]

why 36V?

Why not?
Motor Power Range (Watts) 250-500, 500-1000, 600-1200, 1000-2000

 

[J.R.]

I was just curious because 48V or 52V are more common.

More common in the North American DIY market, but there are more 36 volt ebikes than 48 or 52. I'd bet between Europe and Asia there are more 24 volt bikes running around than 48v ebikes worldwide.

 

[AHicks]

It figures. My new MAC 12t shipped earlier today.

Really like the concept of the built in torque arm to relieve a lot of the stress from the axle

 

[tomjasz]

Also 36V bikes are hard to find, especially with hub motor. I would not say 36V hub drive is more common than 48V.

Remember motors are usually capable of multiple voltages. These days better controllers are programmable over a range of voltages. I’m personally moving back to 36v. Lower prices and longer range in some configurations. I have two new 250w mid drives for my new folders. Lighter and appropriate speeds for busy multiple use paths.

 

[tomjasz]

(I am guessing, I don't know)

Correct! Programmable controllers are common. EM3ev, Grin, Lyen, and others.

 

[tomjasz]

How can the controller adjust voltage?

With a programming cable. MAC are very adaptable motors.

 

[Dewey]

Nice splined torque arm! Is this the one Justin was tinkering with and posted an awesome thread on Endless Sphere? The engineering back and forth commentary was truly great, best ebike discussion I've read this year.

 

[tomjasz]

Nice splined torque arm! Is this the one Justin was tinkering with and posted an awesome thread on Endless Sphere? The engineering back and forth commentary was truly great, best ebike discussion I've read this year.

Indeed!

 

[AHicks]

Correct! Programmable controllers are common. EM3ev, Grin, Lyen, and others.

The programmable controllers can be set up to use different voltages I believe. I don't know that they are capable of taking power from a 48v battery and feeding 36v to a 36v motor. More like the same controller can be used/is able to be set up for use on 36/48/52 volts (or more). The voltage they run on is going to depend on what battery you use - your option. Many motors though will run fine on 36, 48, 52 and higher. Again your call.

Point being, the voltage you run on is more about the battery in use than anything else.

 

[Ravi Kempaiah]

The motor can be run at 48V or 52V.
Here is a video explaining all the features from Grin Tech

 

[GregGritton]

It also looks like they have managed to invent a perpetual motion machine A quote from: https://www.ebikes.ca/product-info/gmac.html

"However, even if you are pedaling the bike without assist, the energy that is expended overcoming this rolling drag in most cases much less than the energy recaptured from regenerative braking. This point is really interesting, since it means that the motor could be run all the time at low powers to overcome the rolling drag using just the energy captured from regen, and still put more energy back than expended "

The video is clearer. They run the motor at low power to overcome the drag from not freewheeling, and simply expect to normally regain more energy by regenerative braking. The latter isn't guaranteed. Obviously, if you are pedaling long distances where, with a normal motor, you wouldn't be using power, and using regenerative braking little, then a normal motor would be more efficient.

 

[harryS]

The video is clearer. They run the motor at low power to overcome the drag from not freewheeling, and simply expect to normally regain more energy by regenerative braking. The latter isn't guaranteed. Obviously, if you are pedaling long distances where, with a normal motor, you wouldn't be using power, and using regenerative braking little, then a normal motor would be more efficient.

Not only more efficient, but a normal geared motor is far more fun to ride in my opinion. I don't want regen if it won't let my motor coast freely. I didn't read the latest info, but believe this motor was initially intended for cargo bikes, as opposed to bikes ridden for sport.

 

[AZOldTech]

How can the controller adjust voltage?
So if you have 48V pack, the controller can adjust it down to 36V? or raise it up to 52V??

Anyways, I was just wondering, because it said 36V, but still said 28mph which suggest that the motor was meant for speed.
48V or 52V is becoming more common, if you want to achieve high wattage with 36V or even 24V, I guess you need to boost up the amperage but if you do that, the battery would have to drain a lot harder which may add extra stress on the battery. (I am guessing, I don't know)

FWIW, my wife's Haibike Sduro Yamaha 36V 500W mid drive ebike, can easily do 28mph with twice the range as my 500W 48V hub drive ebike.

 

[AHicks]

Similar to feeding a 500w gear drive 1000+ watts. They'll handle it, but the bigger question is for how long? A 1500w sprint needs to cool how long prior to having another go at it? You need to watch what's going on here to prevent burn out. Best left to experienced riders demanding top performance running equipment able to monitor their motor's temp.

 

[AHicks]

Temp would be the problem alright. For instance, those gears are composite, and that pinion that drives them is metal. If the motor gets hot, that pinion is doing it's best to transfer heat away, which has a tendency to melt the composite gears.....