Regen Braking for e-bikes ?

[AHicks]

Timpo - OK finally got your point. I was comparing all else being equal on the regen, you were figuring a gear drive hub w/regen vs. DD. That's not always the case though. This new MAC12t doesn't look an awful lot lighter than a 1000 or 1500w DD hub.....

 

[AHicks]

I don't have any pictures, but since you asked the question I have approx 10 miles on direct drive (Stromer ST2).

Maybe you're right, I don't know.

Maybe Giant, Trek, Yamaha, Specialized, Shimano, Panasonic will all move towards direct drive hub motor with regen.

But my personal opinion is, I doubt it.

I have to agree. I doubt they'll work towards direct drive, but it would be no surprise at all for something like Grin's GMAC or something similar with regen to virtually take over the market. That's an outstanding concept to my way of thinking.

 

[AHicks]

Gear Drive vs. DD - Let's go with a 3 lb weight difference just for the sake of this discussion. Again, IMHO, when you add the weight of a bike and rider (in my case 365 lbs total), in the grand scheme of things, how much difference do you think that 3lbs is going to make in a bikes performance? If there were a cool new toy that weighed 3 lbs that would enhance your motor cycles performance, would that be worth it?

Mid drive taking over? Not a chance. The hub drives are MUCH MUCH simpler and less expensive to build. They aren't going anywhere, but they aren't going to be taking over any time real soon.....

 

[Ravi Kempaiah]

I have a 1500w DD now, and below 15-20mph, and in MHO it would be no contest. A 750w+ gear drive will just smoke it! I don't see 1000w DD motors competing with gear drives. Not at legal speeds anyway. Exception being the DD being fed a diet of 52v+ and 40-50a.

That was sarcasm!

What irks me on social forums like this is: people who have no extensive experience on a product start spreading misinformation.
So, I was being sarcastic.

A 750W DD hub motor running at 48V would be simple, powerful, very robust and provide a long service life. They are still the most wisely used motor systems.
Bosch, Shimano, Yamaha and Brose put together won't touch the number of DD hub motors on the road. The sheer number of motors on Asian roads vastly surpasses any mid-drive manufacturer.

 

[AHicks]

That was sarcasm!

What irks me on social forums like this is: people who have no extensive experience on a product start spreading misinformation.
So, I was being sarcastic.

A 750W DD hub motor running at 48V would be simple, powerful, very robust and provide a long service life. They are still the most wisely used motor systems.
Bosch, Shimano, Yamaha and Brose put together won't touch the number of DD hub motors on the road. The sheer number of motors on Asian roads vastly surpasses any mid-drive manufacturer.

My bad for not picking up on your sarcasm. Truth be told, I was kind of surprised at a statement like that coming from you.... We're good. Let's move on.

 

[Feliz]

Yeah I replace my brake pads about the same frequency, that's why I bought them in bulk from AliExpress.
https://www.aliexpress.com/item/329...chweb0_0,searchweb201602_2,searchweb201603_52

Also if primary benefit of regen is to conserve brake pads, I don't think it's worth the added cost.
In addition, regen can conserve rear brake only, which has a lot less effect anyways.

I don't understand why regen can conserve rear brake only. If it's slows the bike down wouldn't it mean using either or both brakes less? Just asking, I guess I'm missing something.

 

[Feliz]

It can conserve rear brake more but it conserves both brakes. If it slows you down it's conserving your brakes.

 

[Trail Cruiser]

Because regen is on the rear hub motor.

The braking force on the bicycle is much greater at the front than rear.
It can be 90% / 10% or maybe 70% / 30%, whatever the situation, there's no secret about it and that's why bicycles (or motorcycles for that matter) have much greater brakes.

So let's say you're in the situation where you want to stop immediately, and you need to apply something like 90% force at front. Now, the rest of 10% is rear. It doesn't matter that 10% comes from 5% rear pad and 5% regen, or 2% rear pad and 8% regen, it is still 10% rear and 90% front.

Let's say you're coasting downhill and applying both brakes to slow down, maybe 60% front and 40% rear, it doesn't matter if it's 10% regen and 30% rear pad, or 35% regen and 5% pad, it makes no difference.

So yea, in any scenario, it will conserve the rear pad, but not front.

There was a time when brake weight transfer concept was not applied to bicycles and the overwhelming majority of bicycles only have rear brakes. As long as the rear wheel does not lift or lose traction, the rear brakes were adequate during that era.

Taking into account the weight transfer to the front when stopping, many new ebikes have bigger front brakes for optimal stopping.

However, if you are only applying mild to moderate braking, the rear brake is enough to stop the ebike.

 

[JRA]

"Because regen is on the rear hub motor."

Not on my two bikes that have front DD motors. One is the Grin AnyAxle that is the same 4kg weight as a typical geared hub motor.

I use regen all the time, and in fact it is the first braking method I have on board that I activate, then the front lever that I can operate easily while holding down the button, and then the rear. To set up mine all I added was a momentary switch button and hooked up the wires to the pre-existing cable of my CA3. Not even enough weight and certainly cost to speak of.

As far as it feeding back into the battery for the amount of use I get out of it as a brake any extra wh's I get in return are just gravy.

 

[tomjasz]

What irks me on social forums like this is: people who have no extensive experience on a product start spreading misinformation.

THIS.

 

[Trail Cruiser]

Since the GMAC is a geared motor (in contrast to direct hub drives), it has quicker acceleration and deceleration which is very helpful in hilly roads. At the 3:20 mark of the video, it demonstrates the use regen braking alone (without the mechanical brake) to stop from a steep downhill. That is impressive in my book.

 

[Feliz]

Listen, you can't tell me anything about motorcycle or bicycle brakes, you're a complete novice, if your even that. Tom had you pegged correctly when he noted you have no personal experience you're just regurgitating what you've read on a forum somewhere and we all know everything on the forums is spot on.

 

[AHicks]

I watched the video a while ago.
I have been looking at Grin chart (on motor simulator) and Juiced specs and videos on YouTube.

To this day, I still don't understand how Juiced goes a lot faster than what Grin chart claims.

Pretty simple. Most trust that sim way more than they trust what a manf. has to say about their bike specs.

 

[Trail Cruiser]

I watched the video a while ago.
I have been looking at Grin chart (on motor simulator) and Juiced specs and videos on YouTube.

To this day, I still don't understand how Juiced goes a lot faster than what Grin chart claims.

I have also been comparing the simulation vs Juicebike's manufacturer claim, many many times.

Keep in mind that there are a number of factors that are not taken into account in the simulation.
1. Tora is an athletic person (an olympian in fact). A seasoned cyclist can kick out 1,000 watts in short bursts. I assume Tora was putting out 400-500 watts of leg power on those top speed runs.
2. The battery's state of charge is not the same as the rated charge. A 52 volt battery is in fact 56 volts when fully charged and has about 10% more power.
3. Aerodynamics affect top speed significantly.
4. The simulation itself is very conservative to accommodate other unaccounted factors.

 

[tomjasz]

Regenerative braking DOES increase the effectiveness of ANY ebike braking system. I'm referring to available controllers and DD/Grin MAC

It is NOT an expensive addition. A quality built controller will have the capability. ALL my EM3ev and Grin controllers come with regen. I believe my Lyen 6FET does too, but I use it on a wimpy MXUS GD.

Why not used by makers discussed here? It's painfully obvious in this thread. Some of us make decisions on confusing and often VERY VERY bad information gleaned from forums, or an OEM that is actually just protecting themselves from know it all customers.

I've had customers on several occasions that didn't stop and think or didn't have a system with a display like the CA series from Grin. Running regen on a long downhill and overcharging is a distinct possibility. A typical n00b won't use due diligence and learn how to mitigate any issues. DD with a CA give us flexibility in programming effective regen.

I come from the world of building and kits. I stay there because I afforded myself the opportunity to try nearly every style of motor available. I can build a much better bike. I choose components that have parts accessibilities and a range of setting for 36V-52V batteries.

I'd be really disappointed to buy a finished eBike with a DD rear motor, and no regen. Silly, just plain silly to not take advantage of regen. ANYTHING that improves eBike braking is a plus, for me.

I still believe most have NEVER truly tested their braking skills and brakes in a panic stop. We are not using the basic lessons from MSF (Motorcycle Safety Foundation).

I know how far I can push all my bikes and use MSF principle applied to eBike riding. REAR regen makes a substantially improved panic stop more effective. PERIOD.

 

[tomjasz]

@3:10

Okay so I guess the regen saves pads, but I don't know if he meant by front?

Ask him, he typically responds.

 

[Feliz]

I think you're lacking the experience. I'm telling you it decreases braking distances. PERIOD.
That's in real-world use with a CA3 and regen capable controller.

If Ravi and Justin aren't enough proof then hey, stick to the forum blather found elsewhere. We get some of the best and brightest here, me excepted. Yet the choice is to tell them and the forum that something engineers have found to be effective, in your book, isn't.

Now I'm truly done headbanging.

You're not excepted, you're one of the brightest and most informed contributors on here. I've just given up responding to this guy.

 

[tomjasz]

You're not excepted, you're one of the brightest and most informed contributors on here. I've just given up responding to this guy.

Fellows like Ravi leave me in the dust. But thanks Feliz. I'm happy we sorted differences and became pals! Now about that bike you're sending me.. Ravi's new bike is the first ready-built eBike that really got me excited. I am really anxious to have you share more!

 

[AHicks]

Timpo,
First, this is NOT about geared hub vs. direct drive. It's about regen! THAT's the point!

You've managed to twist that into front brake pad wear. I don't think anyone else is arguing that point specifically. Not like you are anyway.

If talking an all out stop made at maximum stopping power, to avoid something for instance, I agree with you. The front WILL provide the maximum amount of braking as compared to the rear brake. I think we all know that.

Other times though, when you have plenty of time/room to slow, a regen equipped bike will slow without the front brake even in use! Just like using your engine braking by downshifting through the gears as you approach a stop - without using your brakes. You should easily be able to get that bike down to just a couple miles an hour. Stopping with the brakes at that point not going to take much is it? Or cause much wear?

And regarding MOST regen equipped DD bikes, the regen is not very effective at speeds below 10mph. The armature just isn't turning fast enough at lower speeds. That's what's so cool about the GMAC. Because of the 5:1 gearing, it's armature is turning 5 times faster, making it MUCH more effective at slower speeds (by a factor of 5!). Same as when a direct drive doing 15+ mph where the armature is turning fast enough to produce significant braking power.

 

[AHicks]

The point of Deleted Member 4210 (OP) was, according to Evelo, an ebike manucture, regen is "it is simply not practical."

Which I totally agree, I don't think regen is practical. I think that was the whole point of thread.

No, as you mentioned, it wasn't about saving the brake pad. However I think people started talking about regen is actually practical or something, which I still disagreed, and for some reason saving a brake pad because one of the possible benefit of regen, and the rest went on.

Anyways, no, simply put, regen is not practical.

You need to ride a regen equipped bike. With your opinion, I doubt seriously that you have. Not while riding in any hills anyway. Sometimes you can't just regurgitate other's opinions, stuff you've read. You need to experience it first hand....