Setting up a GMAC for "250W nominal power" ?

[E-HP]

At 3.8 kg, I wouldn't classify the GMAC as "heavy". As far as I know it's the lightest hub motor in this power/torque class. Or do you know an equivalent (or better) ?

Is the point of using the GMAC so that you can sell the ebike as legal, and allow easy modification by the buyer to unlock the potential? If so, then limiting via a programmable controller seems like the best route.

No, the idea is to sell a legal bike, not (easily) possible to unlock.

Well in that case, there's no torque advantage going with the GMAC, since you are choking it by limiting it to 250W. The advantage at that point is that it's a bigger motor and can go longer before melting.

 

[afzal]

All the rules (as far as I have seen) refer to either electric drive train power or ebike power, not motor power. So rating of motor is immaterial it seems, if the controller limits to within the allowed power?

Literally based on the rules, using a controller that limits the power to 250W with a 1MW motor is legal :wink: or I am wrong?

 

[docw009]

Seems like the fun of a mountain bike is running it downhill like a regular bike. Don't you need to keep the the GMAC under power, so it doesn't start engine braking, and is the Grin controller smart enough to do that for a tricky mountain bike descent?

 

[Jil]

All the rules (as far as I have seen) refer to either electric drive train power or ebike power, not motor power. So rating of motor is immaterial it seems, if the controller limits to within the allowed power?

Literally based on the rules, using a controller that limits the power to 250W with a 1MW motor is legal :wink: or I am wrong?

The norm says « 250 watts nominal power ». Many manufacturers interprets this quite freely in proposing motors with peak power around 600 or 800 watts. By the way it’s the same with motorbikes. I have tried a Zero branded as equivalent to a 125cc (11 kW nominal power), it had the acceleration of a 100 hp bike

 

[Jil]

Seems like the fun of a mountain bike is running it downhill like a regular bike. Don't you need to keep the the GMAC under power, so it doesn't start engine braking, and is the Grin controller smart enough to do that for a tricky mountain bike descent?

Yes for sure in mountain biking you need to keep as a minimum the « electronic freewheel » of 20-30 watts.

 

[1boris]

The point is that the motor must be marked as an 250w nominal power motor from the manufactor.If not it is not legal,it does not help if you limit power.
There is already a fantastic kit like this.Its a 250 w mac motor with phaserunner and torque sensor.Expensive,but best 250 kit avaliable IMO.

https://www.ebike-solutions.com/en/shop/electric-bike-conversion-kits/pedelec-conversion-kits/puma-rtr-umbausatz-pedelec-oder-schnelles-e-bike.html

https://www.ebike-solutions.com/en/shop/motoren-und-montagezubehoer/motoren/puma-cst-hinterradmotor-250w.html

 

[john61ct]

The point is that the motor must be marked as an 250w nominal power motor from the manufactor.If not it is not legal,it does not help if you limit power.

Is that true as a standard across the EU?

Actual enforcement must vary by location.

Seems very unreasonable.

 

[1boris]

yes most of EU has 250w limit nomial power,but it doesent mean much.The 250 w tq motor on Haibike flyon puts out more than 900w peak power.but you can not use a 500w motor for example with 48volt 15 a controller.The motor must be marked/rated as a 250w motor by the manufactor.But there is not an upper current limit.Only max speed limit at 25 kmh +-10 prosent.Max 27.5 kmh

 

[ebike4healthandfitness]

yes most of EU has 250w limit nomial power,but it doesent mean much.The 250 w tq motor on Haibike flyon puts out more than 900w peak power.but you can not use a 500w motor for example with 48volt 15 a controller.The motor must be marked/rated as a 250w motor by the manufactor.But there is not an upper current limit.Only max speed limit at 25 kmh +-10 prosent.Max 27.5 kmh

According to the following info from MAC, the hub (which the GMAC is based on) is rated 250 watts to 1000 watts:

(Click on specifications in the link below)

http://www.macmotortech.com/product_detail/53621hr-7d-rear-ebike-hub-motor-14645918166445237.html

 

[ebike4healthandfitness]

yes most of EU has 250w limit nomial power,but it doesent mean much.The 250 w tq motor on Haibike flyon puts out more than 900w peak power.but you can not use a 500w motor for example with 48volt 15 a controller.The motor must be marked/rated as a 250w motor by the manufactor.But there is not an upper current limit.Only max speed limit at 25 kmh +-10 prosent.Max 27.5 kmh

According to the following info from MAC, the hub (which the GMAC is based on) is rated 250 watts to 1000 watts:

(Click on specifications in the link below)

http://www.macmotortech.com/product_detail/53621hr-7d-rear-ebike-hub-motor-14645918166445237.html

 

[ebike4healthandfitness]

yes most of EU has 250w limit nomial power,but it doesent mean much.The 250 w tq motor on Haibike flyon puts out more than 900w peak power.but you can not use a 500w motor for example with 48volt 15 a controller.The motor must be marked/rated as a 250w motor by the manufactor.But there is not an upper current limit.Only max speed limit at 25 kmh +-10 prosent.Max 27.5 kmh

According to the following info from MAC, the hub (which the GMAC is based on) is rated 250 watts to 1000 watts:

(Click on specifications in the link below)

http://www.macmotortech.com/product_detail/53621hr-7d-rear-ebike-hub-motor-14645918166445237.html

 

[markz]

Go read about bogus wattage numbers for motor watts.
https://ebikes.ca/learn/power-ratings.html

Or on video the previous warehouse tour
https://youtu.be/IxB2j-egWcQ?t=721
to about 13:25

Holographic 250W sticker
https://www.ebay.ca/itm/144016596542?hash=item21880ede3e:gUEAAOSwHHtfqEQV

Engraver
https://www.ebay.ca/itm/402724135964?_trkparms=ispr%3D1&hash=item5dc43aa41c:g:vLoAAOSwFFxeXojq&amdata=enc%3AAQAGAAACkPYe5NmHp%252B2JMhMi7yxGiTJkPrKr5t53CooMSQt2orsS%252BMKizvpuEDUfX4dvRWfUzRuTWYIDhCRjlCVTuz2%252BCeaxwO3vr6hYC%252FifOvFIQJcSZE9%252F2%252BCdM35ORWh183SPtmYG8lFzC4V54g9rB85FQcg9IfxuSRFpdURckasPejXx5ad0FWGADA4sWeLS28%252Bu6AilTWIJ7BT35bGNYL5nyjYGF0h5WJvnYZq%252BScIBlaQ3ZZXd3BQO4IEbuolyjZs8pw2leDSd7a3%252BIm2E83oeJ8l2X3WNdlxh6x8mU05BtxBcTKjcBEfvyw%252BBJHZwe72wfOc42PW87SsfhlZ9fd8ITzojWDX9N7Y4gGE1eFBbyoXPOP2%252BTQT8Lw%252Fc2jyeW7avLcF5F2dcWOf8SvkAeaTkMCHyiXaSXtFeuxVlz08cvGQ8ep%252FoeXJW0dejeFxDhhIz4%252Bqa2PVVV7INz%252BgEGqdDr4r5LP9rFrgsDzKWBNuDw7MRM8%252Fzfd1ZHziztya1ailNLgtB4743ty9u50F00llujs%252FoBZ338V%252Bi%252BOmWTJCWPpNMsmsQUHorjXZ7eaNu6Qr0zvVT4K8fdbthJwWcS%252BtlUmrfAtmb9Xn9q8xaxUcRNTyhWp1GuqsgJseVEudozsmoxa5uHCx35%252FFXwxlShZ8IjAr8r5%252B2abC21I23Tv5w%252FycIsnqa1njQ7VuJSc38jVBxpYHU0QKsjUJqEzgdohenA%252FCu9rqyDo6fcX7t2%252BMVEttH5BGe46jGOKXsDQAENvFM70sqRtIf1v7vfhg7EGdLRrh%252BgKpYPXgbMBgA%252BtEE1%252BjDzuNJm6di9s223MsbFiM5nlng7nH5el7mF7JWwNbihM%252FlqId5JFREw5Zho75DSv7s%7Campid%3APL_CLK%7Cclp%3A2334524

ABC123 Stencil
https://www.ebay.ca/itm/383512806752?hash=item594b250560:g:xWYAAOSwTm1eBB17

yes most of EU has 250w limit nomial power,but it doesent mean much.The 250 w tq motor on Haibike flyon puts out more than 900w peak power.but you can not use a 500w motor for example with 48volt 15 a controller.The motor must be marked/rated as a 250w motor by the manufactor.But there is not an upper current limit.Only max speed limit at 25 kmh +-10 prosent.Max 27.5 kmh

 

[ebike4healthandfitness]

According to MAC the 12T with 36v does 25 kph with a 26" wheel. The 10T does 32 kph under the same.

So would GRIN make a special GMAC in 12T or do you plan on using 24v and either 8T or 10T with either 26" or 29" wheel? ( 24v with 8T and 26" wheel comes out to 26 kph. 24v with 10T and 29" is 24 kph)

 

[1boris]

yes most of EU has 250w limit nomial power,but it doesent mean much.The 250 w tq motor on Haibike flyon puts out more than 900w peak power.but you can not use a 500w motor for example with 48volt 15 a controller.The motor must be marked/rated as a 250w motor by the manufactor.But there is not an upper current limit.Only max speed limit at 25 kmh +-10 prosent.Max 27.5 kmh

According to the following info from MAC, the hub (which the GMAC is based on) is rated 250 watts to 1000 watts:

(Click on specifications in the link below)

http://www.macmotortech.com/product_detail/53621hr-7d-rear-ebike-hub-motor-14645918166445237.html

Which means there is a 250w version of the Mac motor.What is your point?

 

[afzal]

The point is that the motor must be marked as an 250w nominal power motor from the manufactor.

Is there an authoritative link/document available in public which mentions that motor must be marked as 250W nominal

In my location (far far away from EU), the rule says "Electric vehicles, having maximum power less than 250W and speed less than 25 kmph are exempt from type approval requiremts" - it doesn't refer specifically to motor rating or mentions about marking requirement in motor.

 

[Jil]

Is there an authoritative link/document available in public which mentions that motor must be marked as 250W nominal

I don't think so.
Here is what French regulations say (derived from European regulations) :
"Cycle à pédalage assisté : cycle équipé d'un moteur auxiliaire électrique d'une puissance nominale continue maximale de 0,25 kilowatt, dont l'alimentation est réduite progressivement et finalement interrompue lorsque le véhicule atteint une vitesse de 25 km/h, ou plus tôt si le cycliste arrête de pédaler"
--> "Pedal assisted cycle: cycle equipped with an electric auxiliary motor with a maximum continuous rated power of 0.25 kilowatt, the power of which is gradually reduced and finally interrupted when the vehicle reaches a speed of 25 km/h, or more early if the cyclist stops pedaling"
https://www.legifrance.gouv.fr/codes/article_lc/LEGIARTI000039478722/

 

[donn]

Very likely they would refer to the EU standards pickworthi mentions above, for the basis of their 250W definition, non?

Laws are written in imprecise natural language, perhaps for the benefit of lawyers who need to feed their families, and I wouldn't bet my life that "moteur auxiliaire électrique" in that context, means only the component that here on endless-sphere we call the "motor." If you swap in your own controller & battery and start feeding that motor 40A, they'll say "no, your controller is part of that auxiliary motor system." Or they won't, who knows. Does anyone here even own a France-legal bicycle, is there a sticker somewhere?

The "arrête de pédaler" part is like the law here in my state, in that it requires the pedals to be operated - but doesn't require any sort of correspondence between pedal input force or cadence. I think that's typical of such laws, if only because the common implementation is split between force ("torque") and cadence and the legislators don't care to get into that. So while it's commonly implemented with one of those two proportional pedal assist systems, it doesn't have to be that fancy, just on / off.

 

[Jil]

Instead you could look at something like the SX2 hub motor (from Grin with it's internal temp sensor) combined with the BaseRunner controller. This way you don't have to carry around that extra Kg or so of weight and you get a more efficient setup. You get the same temperature management/protection when used with the CA3 so you're not going to burn it up.

Finally I'm thinking that this Shengyi SX2 motor could be a good and reliable option.
Even it's not "250 watts branded", it has, as per the Grin simulator, an excellent efficiency, better than the G310 and equivalent to the GMAC, for a lower weight and stealther profile.
An option to keep a perfectly legal system is to limit the maximum power to ~300 watts at battery output. Taking into account the maximum efficiency of the motor (~84-85%), it will translate into a ~250 watts mechanical power delivered by the motor.
It will also be adapted for the kind of ebike I'm seeking to create, i.e. an ebike where the motor is just an assist, not more. Any hill should be doable, even loaded, with 100 human watts + 250 mechanical watts. After all, a top-pro climber puts on average 400 watts during 30mn on the ventoux climb : https://www.lefigaro.fr/sciences/2018/07/20/01008-20180720ARTFIG00181-tour-de-france-decrypter-la-puissance-des-coureurs-pour-lutter-contre-le-dopage.php
With this kind of power limit and a thermal rollback, I can envision a very long lifetime for the motor (which is a major point for me).

 

[Jil]

I am currently testing my GMAC in the Pyrénées mountains.
Surly Krampus, 29+ tires, GMAC 8T, 52V battery, Phaserunner. I use it with torque sensor and maximum battery output of 300 watts (i.e. ~250 mechanical watts at the motor).

Finally, for such use, I found that the GMAC is not overkill. I'm 95kg (~120 kg total weight), and I reached 95°C with 300 watts continuous at the end of a long and steep hill (9 km at 9.5% average inclination, with some short parts much steeper).
So I tend to think that a Shengyi SX2 (or worse, a Bafang G310) would be too small for intensive use in mountainous areas. And that the GMAC seems to be the way to go. In addition, during the descent, I took back via regen 35% of the energy spent during the climb. Which I could not do with any other geared motor than the GMAC.

Your thoughts ? Does it make sense to have a GMAC+Baserunner (the Phaserunner is ovekill) on an ebike limited to around 300 watts at battery output ? Or the Shengyi SX2+Baserunner will be enough ?
The idea is to have this motor on bikes dedicated to travel/bikepacking, and then able to climb steep hills fully loaded.

 

[sleepy_tired]

Instead you could look at something like the SX2 hub motor (from Grin with it's internal temp sensor) combined with the BaseRunner controller. This way you don't have to carry around that extra Kg or so of weight and you get a more efficient setup. You get the same temperature management/protection when used with the CA3 so you're not going to burn it up.

Finally I'm thinking that this Shengyi SX2 motor could be a good and reliable option.

I think so as well. It's a safe choice and a robust small motor. If the electronic freewheel feature of the Gmac is attractive then I suppose you could get the same thing done for the SX2 if you are ordering a bunch of motors.

This way you can get your start and see what it's like selling these things. This way you can get a better feel for what it's like to sell these things and deal with the legalities first hand. Then if you feel comfortable go with the Gmac as a option or upgrade or something. I donno.

 

[E-HP]

If the electronic freewheel feature of the Gmac is attractive then I suppose you could get the same thing done for the SX2 if you are ordering a bunch of motors.

Is electronic freewheeling something needed for the SX2? It has a clutch (not locked), and I thought the GMAC would only need it since it has a locked clutch.

 

[Chalo]

Is the point of using the GMAC so that you can sell the ebike as legal, and allow easy modification by the buyer to unlock the potential? If so, then limiting via a programmable controller seems like the best route.

No, the idea is to sell a legal bike, not (easily) possible to unlock.

Grin developed that motor intensively; I'm certain they have power-in versus power-out maps for at least one voltage, perhaps several.

My point is, if you want to be certain a bike is legal while maximizing its performance, program a controller to deliver however many amps at whatever RPM cause the motor to output 250W across its entire speed range.

250W output at 5 RPM would be a lot of torque and a lot of acceleration. Probably the motor won't do that, but at some low RPM it will. Then as RPMs rise, it can taper off the current so it delivers 250W output right up to the maximum speed limit.

This method isn't easy, but nobody can decide it isn't legal. Watts are watts. If you accomplish it, you'll have the best performing EU legal electric bicycle anywhere.

If you can do it reliably, there would be no reason to make the controller programmable by the user.

 

[Jil]

My point is, if you want to be certain a bike is legal while maximizing its performance, program a controller to deliver however many amps at whatever RPM cause the motor to output 250W across its entire speed range.

250W output at 5 RPM would be a lot of torque and a lot of acceleration. Probably the motor won't do that, but at some low RPM it will. Then as RPMs rise, it can taper off the current so it delivers 250W output right up to the maximum speed limit.

The Cycle Analyst allows to set up a maximum power at battery output, whatever the amps. I'm not sure it turns out exactly in real instant power, but in any case it's fully legal as per EU definition : I have set it at 300 watts, which turns into 250 mechanical watts at the motor at the highest efficiency ratio of the GMAC (around 84%, it is less at low speed uphill). With an adapted ratio of the transmission (for human power), I (and my girlfriend also) found this electrical power sufficent to climb more or less anything until now.
A test offroad with very steep climbs (still with this 300 watts limit) is planned for this WE, to confirm this feeling

 

[Jil]

Is electronic freewheeling something needed for the SX2? It has a clutch (not locked), and I thought the GMAC would only need it since it has a locked clutch.

The SX2 has a clutch, so it has no need of electronic freewheel, nor provides regenerative braking.
It's an interesting alternative to the GMAC (I have definitively eleminated the smaller G310) provided that regen is not needed. It is what I need to figure out. For ebike travel, regen braking seems appealing, to extend the range and strongly limit the use of mechanical brakes. But it is at the expenses of a bike more difficult to move if you end up with empty batteries...

On the Grin's trip simulator, with 130kg total load, 100 human watts + 230 electric watts, on hilly terrain, the GMAC with regen (and speed limit at 25 kph) is much more efficient than a central motor (BBS) : 3.4 vs 5.7 Wh/km , despite its lower efficiency uphill.
BBS2 : https://ebikes.ca/tools/trip-simulator.html?m=MBBS02&v=mountain&ms=130&h=100&w=28.5&sp=25&wv=0&b=B36LiGox10&c=cust_pl96_rl96_bl6_cr0.02&rg=false&t=21&ct=21&st=21&i=man&p=16A0285H4OA45U5F89A29E5HBQA6DR3SFN9THM3TJR9V&mo=&md=&x=359.53&y=2161.07&lx=&rx=&rw=
GMAC/regen : https://ebikes.ca/tools/trip-simulator.html?m=GMAC10T&v=mountain&ms=130&h=100&w=28.5&sp=25&wv=0&b=B36LiGox10&c=cust_pl96_rl96_bl6_cr0.02&rg=true&t=21&ct=21&st=21&i=man&p=16A0285H4OA45U5F89A29E5HBQA6DR3SFN9THM3TJR9V&mo=&md=&x=359.53&y=2161.07&lx=&rx=&rw=