Using a geared hub motor with regen?

[mikebikerad]

Hi ES,

I have been playing around internet all morning but can't find good info....

Has anyone ever used a geared hubby with Regen either by disabling the freewheeling or are there any geared motors without freewheeling?

I know this could damage the gears but still interested.

Thanks

 

[cal3thousand]

Hi ES,

I have been playing around internet all morning but can't find good info....

Has anyone ever used a geared hubby with Regen either by disabling the freewheeling or are there any geared motors without freewheeling?

I know this could damage the gears but still interested.

Thanks

Some Sanyo geared motors (iirc) were not clutched so they could perform regen. I also heard some information about a unit that could be controlled remotely, but I don't know exactly.

 

[dogman dan]

One of the fusin motors i tested had regen enabled, by having a clutch permanently locked somehow. Since it was a very small motor, I found the regen braking effect to be quite underwhelming.

I have no idea if it was really just the small motor, or if the controller limited it. 5 amps regen was the max. You could barely tell it was working.

 

[Chalo]

Has anyone ever used a geared hubby with Regen either by disabling the freewheeling or are there any geared motors without freewheeling?

I know this could damage the gears but still interested.

How come? Brakes are better for braking, and coasting extends range far more than regeneration does.

 

[Russell]

Yeah like the guys above mentioned you can do it if you lock the clutch so it doesn't freewheel. After a hall sensor failed on a small Bafang geared motor I locked the clutch mechanism with Cold Weld.

(see here: http://endless-sphere.com/forums/viewtopic.php?f=4&t=10458&hilit=45&start=45#p212576 )

It would have been better to actually weld the clutch since the Cold Weld only held up 932 miles. The motor and gears worked just fine in this configuration though I wasn't using a regen controller. I did get a miniscule amount of regen on significant downgrades when my speed exceeded the no-load speed.

-R

 

[Hillhater]

... Brakes are better for braking, and coasting extends range far more than regeneration does.

+1 .. best advice regarding regen that i have heard for a long time ! :wink:

 

[Russell]

I'd say it depends on the terrain. For me regen braking would be of little use but if someone has a lot of long or steep decents where they need to control their speed then why not recover the energy through regen braking.

-R

 

[mikebikerad]

That is all great info thanks cal3thousand, dogman, and russell. Ill order some motors, get out the welder, and try not to rip apart some gears. Hopefully I can turn the regen amps way up and get some good stopping power without damaging things. Any other data would be awesome, ill post pics and results here.

(chalo&hillhater)I love Regen, I live in a hilly area and don't like to change my brake pads often... I get 6-8% back and I get freewheeling until I hit the regen button, it just makes sense. but.... I am also running a 5404 so the braking is impressive

 

[mikebikerad]

Dogman: Did you have the same experience with that fusin as these people http://fusinmotors.com/distribution/regen-brake-t29.html
No noticeable regen cause freewheel was active on these motors

 

[magic carpet]

Has anyone ever used a geared hubby with Regen either by disabling the freewheeling or are there any geared motors without freewheeling?

I know this could damage the gears but still interested.

How come? Brakes are better for braking, and coasting extends range far more than regeneration does.

True. Plus regen does very little. Best feature is it saves brake pads.

 

[Chalo]

Brakes are better for braking, and coasting extends range far more than regeneration does.

True. Plus regen does very little. Best feature is it saves brake pads.

Brake pads are $4 to $12 a pair at my shop. $6 per brake to have me install them for you. Repairing a frame or hub motor axle damaged by the reversing torque of regen braking is a lot more expensive and time-consuming.

 

[dogman dan]

The fusin prototype they sent me for testing had the freewheel locked. So it did do regen. It just didn't have the stopping power of a 5304 in regen.

 

[Alan B]

The drag of a locked clutch geared motor is probably a lot more annoying than the drag of a DD hub, spinning the motor six times the wheel speed or so (depending on the particular gear ratio).

Make CERTAIN you have good dual torque arms, or better yet clamping dropouts, and NordLock washers, and check nut tightness frequently.

Regen works GREAT on big descents. My dual 160mm front rotors get so hot they turn black, that can't be good for them. How long will they last? How much more will they take before they fade or fail?

Regen would be a LOT more useful if it was truly variable.

 

[hjns]

Brakes are better for braking, and coasting extends range far more than regeneration does.

True. Plus regen does very little. Best feature is it saves brake pads.

Brake pads are $4 to $12 a pair at my shop. $6 per brake to have me install them for you. Repairing a frame or hub motor axle damaged by the reversing torque of regen braking is a lot more expensive and time-consuming.

Hmm. In my area, I would pass by your shop every week. I can buy a whole new cromotor after a year for that money....

 

[Chalo]

Brake pads are $4 to $12 a pair at my shop. $6 per brake to have me install them for you. Repairing a frame or hub motor axle damaged by the reversing torque of regen braking is a lot more expensive and time-consuming.

Hmm. In my area, I would pass by your shop every week. I can buy a whole new cromotor after a year for that money....

You're using the wrong brake pads, then. To be frank, I have never seen a pair of Kool Stop Salmon pads (the $12 kind) completely worn out from street riding (only from mud or improper adjustment). I've been in the bike mechanic game for over 20 years now.

But in a place where you are always on the power or on the brakes, regen does make more sense than it does for most places. You just have to take precautions to immobilize the axle, since it really isn't big enough or the right shape to transmit that much reversing torque routinely.

Chalo

 

[cal3thousand]

Brake pads are $4 to $12 a pair at my shop. $6 per brake to have me install them for you. Repairing a frame or hub motor axle damaged by the reversing torque of regen braking is a lot more expensive and time-consuming.

Hmm. In my area, I would pass by your shop every week. I can buy a whole new cromotor after a year for that money....

You're using the wrong brake pads, then. To be frank, I have never seen a pair of Kool Stop Salmon pads (the $12 kind) completely worn out from street riding (only from mud or improper adjustment). I've been in the bike mechanic game for over 20 years now.

But in a place where you are always on the power or on the brakes, regen does make more sense than it does for most places. You just have to take precautions to immobilize the axle, since it really isn't big enough or the right shape to transmit that much reversing torque routinely.

Chalo

But that's not e-bike speeds and momentums...

 

[hjns]

You're using the wrong brake pads, then. To be frank, I have never seen a pair of Kool Stop Salmon pads (the $12 kind) completely worn out from street riding (only from mud or improper adjustment). I've been in the bike mechanic game for over 20 years now.

But in a place where you are always on the power or on the brakes, regen does make more sense than it does for most places. You just have to take precautions to immobilize the axle, since it really isn't big enough or the right shape to transmit that much reversing torque routinely.

Chalo

Hmm. Could be, but I do not want to find out.

And yes, I did take quite some precautions to immobilize the axle. I think this is a very important point that you make.

On every side, the axle is held by an 8mm steel plate + the DrBass torque arms of approximately 8mm. The torque arms are connected to the steel plate with two M6 bolts, that fit directly into the threaded holes in the steel plate. So on each side there is 16mm of steel holding the axle tight.

The axle is positioned in the corner, and does not move at all. Regen or heavy accelerating since the time I got my cromotor have not yet resulted in even the slightest loosening of the axle nuts. I know, because I check every week.

 

[amberwolf]

One of the fusin motors i tested had regen enabled, by having a clutch permanently locked somehow. Since it was a very small motor, I found the regen braking effect to be quite underwhelming.

I have no idea if it was really just the small motor, or if the controller limited it. 5 amps regen was the max. You could barely tell it was working.

AFAICT without yet having tried that same motor on a different controller, it is the controller itself that limits it (as it was only a 6FET and designed to be pretty strict about it's limiting for motor or braking use).

FWIW the way it is made is that it has no clutch at all, just a 3-fingered "Y" mount for the planet gears, fixed to the axle so that it can never freewheel, essentially making it a geared-down direct-drive (if that makes sense).


Theoretically a geared hub should do *better* regen braking than a true DD hub, as the gears help increase the motor speed...but the heat generated during braking has nowhere to go quickly so it will help heat the hub up internally faster than if it were not being used to brake. If it's already being used heavily as a motor, it may overheat it. This is one of the several tests I need to do with the Fusin above, if I ever get the time.


One thing you must seriously consider, though, is that the torque of a geared hub is much higher than that of an equivalent-power DD hub, and so the regen at similar currents will also be higher torque, requiring stronger dropouts and a tight (perfect) fit in them and/or the torque arms/plates, or you will end up spinning it's axle in the dropouts. I promise you won't like it.


Also consider that as others pointed out, there will be (a lot!) more drag on the wheel when not applying power, trying to just coast (or pedal!).


What would be ideal is to build or modify a geared hub motor so that it uses a clutch you can engage or disengage yourself, from outside the motor. Like an electric clutch on a car's A/C compressor, for instance. If you did that, you could coast when you wanted to, and regen when you brake. Of course, you can do this with a mid-drive easily, by having no freewheel in the chain or belt to the wheel, just a clutch.

 

[Russell]

The drag of a locked clutch geared motor is probably a lot more annoying than the drag of a DD hub, spinning the motor six times the wheel speed or so (depending on the particular gear ratio).

Nah, my 250W Bafang with the clutch locked didn't present much drag, not any more than a 9C DD motor anyway.

-R