Freegen - New Hub Motor Innovation That Is Definitely Worth Watching

[m@Robertson]

The benefits of this go far beyond just adding the feature of regen to a geared hub motor. The benefits of regen variable on the fly to improve performance coming down steep hills would border on being revolutionary. To see that you have to stick with the video for awhile to see the part where they get into the braking performance. Also this softens the stresses put onto torque arms.

 

[Slaphappygamer]

I have lots of hills on my regular commute. I’m thinking of locking my clutch, but this seems very nice. Though, I would need the super harness and a V6 BaseRunner. I just bought the CA3 and BaseRunnerV5. Welding my clutch would make more sense in my scenario.

Here is the Q&A that took place after the announcement.

 

[PCeBiker]

I can't wait to get one, so I'm just going to drill through my motor and mount my brake rotor to the planetary gear.

 

[Slaphappygamer]

I can't wait to get one, so I'm just going to drill through my motor and mount my brake rotor to the planetary gear.

I first thought that’s what they did. That’s the idea. There is a machined part they made that butts against the motor shell and the planetary gears. I’m really curious what others will use to achieve the same effect.

 

[PCeBiker]

It's a bit like this,..

You'd weld the smaller bearing inside the larger bearing, then connect your rotor to the welded races.

It turns like a wheel inside a wheel,..

 

[gromike]

This was posted on another forum by Alon-CargeBike:

"But let me just give a quick clarification -
The controller applies motor braking torque that matches precisely the mechanical braking torque applied by the user, this is done by measuring wheel speed and motor speed and allowing the disc to slip ever so slightly - keeping motor speed a bit below wheel speed.
So that when the user brakes harder the motor speed will increase and the controller will respond by increasing brake torque in order to maintain that wheel motor speed difference.
The opposite accurs when the user brakes lighter.
The result is a totally natural brake feel and enough brake torque to skid the wheel if necessary."

 

[Stefan Mikes]

Is anyone here aware that the rear wheel is only responsible for 30% of the bike stopping power, which would result in meagre regen?
I wonder how safe the concept is.
And whether it will ever get commercialized.

 

[il Munduato]

Is anyone here aware that the rear wheel is only responsible for 30% of the bike stopping power, which would result in meagre regen?
I wonder how safe the concept is.
And whether it will ever get commercialized.

Not if you apply mostly the rear brake and feather the front as needed.
Then add that most braking situations do not require 100% stopping power and your 30% is meaningless.

 

[Chargeride]

Im still trying to conceptualise the mechanics of this, its so complicated even the inventors didnt forsee many outcomes like the torque arm effect.

If youre just riding , will the brake disc be spinning faster than the hub?

 

[Stefan Mikes]

Not if you apply mostly the rear brake and feather the front as needed.
Then add that most braking situations do not require 100% stopping power and your 30% is meaningless.

The rear brake is just 30% effective. Breaking with just the rear wheel is dangerous; ever wondered why cars have brakes in each of four wheels?
If the front brake has to be applied (and it has to), the majority of the braking/slowing down energy will just be dissipated as heat but not regenerated.

 

[m@Robertson]

Nobody is ever saying you apply only rear brakes. You created that part in your head Braking would of course continue as normal. Unless you did an awd bike which is a whole other pablum-spluttering jihad we can set aside for now.

Not if you apply mostly the rear brake and feather the front as needed.
Then add that most braking situations do not require 100% stopping power and your 30% is meaningless.

Correct. Rear-engagement-first stabilizes the bike so that application of the front brakes don't result in nasty consequences, for starters. Try riding down a steep hill at speed and using the front brakes first. You'll get what you deserve with that rookie move.

Breaking with just the rear wheel is dangerous

This is like saying front braking is dangerous because it will send you over the handlebars (which it certainly can). Front braking is unsafe only if you do it wrong. Same goes for rear braking.

 

[PCeBiker]

Im still trying to conceptualise the mechanics of this, its so complicated even the inventors didnt forsee many outcomes like the torque arm effect.

I smoked a Vado, and got to thinking about that.

When the wheel/hub motor is braking, there is very little force on the brake rotor itself, and even that small amount of force is transmitted directly through the brake disk to the frame of the bike leaving the axle spinning freely, so almost no torque affect on the axle.

If youre just riding , will the brake disc be spinning faster than the hub?

I'm guessing that the rotor never spins faster than the "wheel". Only slower but just slightly.
As the brake disc starts to slow down, the regenerative energy is increased which reduces the force on the brake rotor, so equalization can occur.

Almost all of the momentum force is turned into electrical energy with very little energy going into the brake rotor.

 

[m@Robertson]

If youre just riding , will the brake disc be spinning faster than the hub?

Fast-fwd the vid to 4:36 - the Automatic Brake Modulation' link on the video in the description. You have to see the vid on Youtube to see the subject jumps.

 

[m@Robertson]

The rear brake is just 30% effective.

I just noticed their prototype testing was with a front wheel motor. So ...

;-)

 

[PCeBiker]

Its not spinning at all. They show that in the video.

Sure it does. Watch the video again.

It's the rpm of the brake disk relative to the rpm of the motor that regulates the regenerative effect.

It compares hall sensor data to speed sensor data to determine how much regeneration force to apply.

The guys had to make a new speed sensor because 6 magnets weren't enough and they needed something more granular.
Then they realized that 6 magnets is enough.

 

[m@Robertson]

Sure it does. Watch the video again.

You caught that post before I rewrote it SOMEWHERE in there is a pic of the rotor sitting still while coasting. Must have been some kind of test. The link I replaced it with is where I caught my mistake.

 

[PCeBiker]

I do see a potential for failure though.

If you Lock Up the brake rotor, that should send your regeneration to maximum and Lock Up your tire on the road,.. but if the regeneration doesn't kick-in, for whatever reason, then your motor will only brake with the cogging effect of the magnets in a regular motor.

So that wheel will just have a bit of drag on it even with the brake rotor locked up.

However,.. I'd rather have the brake fail and not work, than fail by spontaneously seizing up.


And with that being said,..
I supposed that the system could fail catastrophically if it erroneously goes to maximum regeneration out of nowhere and your wheel locks up.

I think that might be possible even if you didn't have a brake rotor installed?

 

[m@Robertson]

It doesn't look like its possible to actually do that (the lockup). The regen not kicking in seems like a super obvious issue I would have to think is addressed but not immediately obvious. I mean... nobody is going to assume that kind of liability or even that level of personal risk on a prototype-phase product.

 

[PCeBiker]

I mean... nobody is going to assume that kind of liability or even that level of personal risk on a prototype-phase product.

I AM !!

I'll gladly pay Grin up to $1000 CAD for one of those prototypes connected to a BAFANG rear, geared hub G06 series fat motor with a proper 27.5" X 2.8" rim attached.

I am no stranger to failure.

I've gone over my handlebars so many times that I learned to turn my head to the side so I don't land on my face.

It Was FUN learning that trick !!

Remember when Archimedes farted in the bathtub, discovered a new scientific principle, and ran down the street baked yelling Eureka !!!

EDIT: I'm sure that I typed naked not baked, but baked is funnier.

I bet the crazy bastard was stoned and naked, yelling his head off.

Then he weighed the kings crown, and measured its volumetric displacement of water to find out that the goldsmith was stealing gold and replacing it with lead.

 

[PCeBiker]

I supposed that the system could fail catastrophically if it erroneously goes to maximum regeneration out of nowhere and your wheel locks up.

I think that might be possible even if you didn't have a brake rotor installed?

It doesn't look like its possible to actually do that (the lockup).

I think your right?

I'll bet that's why the disconnected torque arm didn't spin?

And I'll bet that a second torque arm is needed in case my scenario plays out as a failure?

Then the braking force goes through to the axle where the reverse torque arm then actively transmits force from the axle to the frame.



I'm really liking this whole idea and still want one, even though I live in an almost Perfectly Flat area, where I almost never need to use the brakes.

I barely need to hold the handlebars at all, let alone use my brakes.