Looking for hub motor for regen purposes

[ebike4healthandfitness]

One thing I wish we could get was a front direct drive hub that deleted the disc brake mount and used that 18mm+ space instead for a wider stator. Then use this with front rim brake (mounted via the hole in the fork used to mount the fender).

18mm extra stator width is going to soak up heat a lot better than any disc brake could. This especially with statorade in the hub.

This, of course, with the appropriate torque arms (e.g. Grin v7) and secured with castle nuts and cotter pins.

 

[E-HP]

I have a mongoose envoy cargo bike with a 52v bbshd. However, I also want to a dd a rear hub motor for regen purposes. Ideally, I want a fully built wheel with something similar to an mtx39 as the rim but the bare essentials I've narrowed it to are a 750w+ dd motor with 142mm dropout. The dropout width is really restricting my options so I'd like some recommendations on compatible motors. The controller I plan to use is some form of vesc.

tl.dr:
- need recommendation on 750w+ dd hub motor with 142mm dropout for regen

I’m sure someone has already mentioned it, but my quick scan didn’t see it, but there’s a recent thread regarding running a bbshd through a dd hub motor and the resulting case failure. The case normally only needs to deal with human leg power, not 1000w, plus leg power. The thread has some pics of cracked/broken cases. Even if it’s rare, you may want to consider that a failure like that could leave you stranded, and maybe without the ability to even push the bike.

 

[Potato011]

I’m sure someone has already mentioned it, but my quick scan didn’t see it, but there’s a recent thread regarding running a bbshd through a dd hub motor and the resulting case failure. The case normally only needs to deal with human leg power, not 1000w, plus leg power. The thread has some pics of cracked/broken cases. Even if it’s rare, you may want to consider that a failure like that could leave you stranded, and maybe without the ability to even push the bike.

Interesting. I will have to look into that. Can I get a link to the thread?

 

[99zip99]

They have freewheel and cassette motors I think a five-speed on some motors is still 135 a 7-speed might be 142 with washers that go inside the free will as the shoulders on the axle could be below the 7th and six gear the frame has to hit the shoulder or the stacked up washers to the shoulder to the frame.
So freewheel or cassette ?

 

[ebike4healthandfitness]

They have freewheel and cassette motors I think a five-speed on some motors is still 135 a 7-speed might be 142 with washers that go inside the free will as the shoulders on the axle could be below the 7th and six gear the frame has to hit the shoulder or the stacked up washers to the shoulder to the frame.
So freewheel or cassette ?

His bike is 8 speed cassette.

 

[PaPaSteve]

Watch this Grin video showing a great idea for a regen hub motor.
" Freegen "

 

[Chalo]

Take note that if your purpose for adding a hub motor is braking, you most definitely should put it in the front wheel. That way you avoid weakening the more heavily loaded rear wheel, you completely sidestep the risk of breaking your motor side cover, and you have your supplementary braking in the wheel that can use more of it.

It's still not a brake, though, and won't work as well as a brake even though it weighs 10-20 times as much as one.

 

[PaPaSteve]

In the car world many of the electric cars have "one pedal" driving mode where the vehicle can be driven completely to a full stop by the accelerator pedal.
The electric propulsion motor does the job as a functional brake.
So much so that there are plenty of examples that due to the non use of the mechanical brakes it results with frozen pistons inside the caliper, rusty discs, glazed pads and other such unintended consequences.
Mostly see this issue in the rust belt areas of the country.
Keeping in mind, car motors, controllers, batteries have cooling systems to absorb the regen braking heat.
For me, the most logical solution is to remove and sell the mid-drive motor in favor of the rear dd hub motor that has built in regen.

 

[ebike4healthandfitness]

There are plenty of examples that due to the non use of the mechanical brakes it results with frozen pistons inside the caliper, rusty discs, glazed pads and other such unintended consequences.
Mostly see this issue in the rust belt areas of the country.

Yep, and that is one reason why drum brakes are making a comeback in electric cars.

 

[99zip99]

I only got 8% on Regen. And when my bike was kicking back 2200 watts to the battery I had two torque arms. The norlock locking washers and it's still wanted to Rock it back and forth if it could it was a wild stallion. Yes I'm talking about the region I had with that power velocity controller I don't think anyone has a working power velocity controller today maybe they're 24 fet one.
What controller are you going to use that has a regen mode that you can vary.
Remember I just have rim brakes. I will plug in my regen on my em3ev 36-72 Infinieon Base controller.
A great controller except it won't saturate my motor and keeps giving 40 amps at 46 miles an hour it probably goes faster. Need quality tires.

 

[ebike4healthandfitness]

Interesting. I will have to look into that. Can I get a link to the thread?

The issue is with multi-speed freewheel designs especially those with an aluminum thread for the freewheel but it can still happen with side panels using steel threads for the freewheel. This because when pedaling in the outer gears a bending force is transmitted to the side panel which causes the big side panel to flex which later develop into cracks.

As far as cassette designs go I haven't found any reports though realize cassette hub motors are a lot more rare. With that noted, realize due to the placement of the bearing on a cassette freehub being more outboard (see diagram below) the bending force on the side panel would be much less.



Major consideration for a freehub hub motor and mid drive should be the the thickness (and porosity) of the side panel, the strength of the freehub, the availability of replacement freehubs and the ease of which the freehub can be replaced should it get damaged. Remember mid drive is going to add stress beyond which a typical freehub was designed and some companies like DT Swiss have had to develop beefed up versions of the freehubs to deal with the extra power.

 

[Potato011]

The issue is with multi-speed freewheel designs especially those with an aluminum thread for the freewheel but it can still happen with side panels using steel threads for the freewheel. This because when pedaling in the outer gears a bending force is transmitted to the side panel which causes the big side panel to flex which later develop into cracks.

As far as cassette designs go I haven't found any reports though realize cassette hub motors are a lot more rare. With that noted, realize due to the placement of the bearing on a cassette freehub being more outboard (see diagram below) the bending force on the side panel would be much less.

View attachment 360774

Major consideration for a freehub hub motor and mid drive should be the the thickness (and porosity) of the side panel, the strength of the freehub, the availability of replacement freehubs and the ease of which the freehub can be replaced should it get damaged. Remember mid drive is going to add stress beyond which a typical freehub was designed and some companies like DT Swiss have had to develop beefed up versions of the freehubs to deal with the extra power.

Interesting info. Given the limited documentation on this, I guess whatever hub i pick will be a nice experiment. The stock rear hub on the envoy has handled the bbshd no problem. Its been around three years with lots of abuse so I guess whatever specs that one has is a good starting point.

 

[E-HP]

Interesting info. Given the limited documentation on this, I guess whatever hub i pick will be a nice experiment. The stock rear hub on the envoy has handled the bbshd no problem. Its been around three years with lots of abuse so I guess whatever specs that one has is a good starting point.

As long as you’re making decisions understanding the risks, then my conscious is clear.
You may want to periodically check the tiny screws used to hold the side cover on to the motor/spoke flanges. They’re main purpose is to hold the side cover on and probably weren’t contemplated to be a component used to transmit power to the rear tire. I don’t think the screws would fail, just the unknown cast metal the flanges are made of might strip out. In any case, that wouldn’t be a catastrophic failure, like sidecover breaking, but worth a routine check.

 

[99zip99]

I bought the newest greatest mid drive 2 years ago. A Cyc pro 1 Gen 2 Bluetooth. 36-72v . It could never be programmed and the 72 volt Samsung 40t pack would just tear up the cassette and maybe the free hub underneath I put another 9-speed cassette in there. After year and a half Cyc admit it thereproblems on their first production line of ASI 855 controller. They sold me a replacement for $60 they're X6 Bluetooth model plus $60 shipping. It now seems to work great with the 52 volt battery. I've had double knee surgery so no peddling for me. As it has a torque base sensor in the bottom bracket. I paid $1,150 for it. I'm back to my muxs 3,000 with the 72v triangle battery. So nevermore than100 miles on that mid drive.
I'm going to put just the complete motor kit up for sale.
But it's hanging now and you can see how it works.
Oh you already have a bafang HD mid-drive ?
I wrote this as a cautionary tale of the newest and the he greatest a lot of times you got to get lucky. Even with batteries, but if I could I'd have a Bluetooth BMS that wait you can see and monitor the regen.
Wow I'm really thinking about this that's good as I'm still doing rehab or downtime.

 

[rudivb]

Any update on this?

I've just ordered Magura MT5s actually to upgrade my Deore M615, mainly hoping less pad wear and just better overall stopping power and modulation. By switching to metallic pads I could increase from 600km to 1000km on pads, but still that's every few weeks for me. If the MT5s aren't good enough I was gonna look at other options like a hub for regen indeed (I also run BBHSD), another option would be proper "motorcycle" type brakes, I believe because of the Surron trend there might be some options out there, although pricy.

 

[Potato011]

Any update on this?

I've just ordered Magura MT5s actually to upgrade my Deore M615, mainly hoping less pad wear and just better overall stopping power and modulation. By switching to metallic pads I could increase from 600km to 1000km on pads, but still that's every few weeks for me. If the MT5s aren't good enough I was gonna look at other options like a hub for regen indeed (I also run BBHSD), another option would be proper "motorcycle" type brakes, I believe because of the Surron trend there might be some options out there, although pricy.

I have switched over to metallics and they are performing better but I still want to experiment with hub regen. The only issue is that for reliability with a middrive, I need a casette hub but high power dd hub motors with casettes are quite pricey. Will hold off for now.

 

[rudivb]

I have switched over to metallics and they are performing better but I still want to experiment with hub regen. The only issue is that for reliability with a middrive, I need a casette hub but high power dd hub motors with casettes are quite pricey. Will hold off for now.

Why don't you do it on the front?
Would be easier to assemble/disassemble, probably better weight balance and "braking" on the front is always more effective.

 

[Potato011]

Why don't you do it on the front?
Would be easier to assemble/disassemble, probably better weight balance and "braking" on the front is always more effective.

I'm not confident my fork can handle the deceleration forces. Will have to think about it but if I do decide on a front hub, the bike needs a stronger fork. Also, I'm in the middle of changing out the rims and already swapped the front rim with a new mtx39.

 

[rudivb]

I'm not confident my fork can handle the deceleration forces. Will have to think about it but if I do decide on a front hub, the bike needs a stronger fork. Also, I'm in the middle of changing out the rims and already swapped the front rim with a new mtx39.

Hmmm yeah I didn't think about that, I thought if it can manage the disc brakes it can manage the regen braking, but I guess the extra weight is the issue? Not an expert in the whole force calculations and I'm already running bigger rotors than my fork and frame are specced for (203mm, specced for 180mm). But I hope the MT5s will be adequate for me, total weight is not as heavy as yours at about 115kg (250lbs) total including myself.

 

[ebike4healthandfitness]

Also, I'm in the middle of changing out the rims and already swapped the front rim with a new mtx39.

Why are you changing out your rims?

From the link below:

"Worth noting: The stock Mongoose wheels never let me down and never took so much as a shimmy; always staying true."

Mongoose Envoy – Chapter 6 (Odds & Ends)

Introduction: The Mongoose Envoy Project Chapter 1: The Raised Rear Deck Chapter 2: Better Brakes Chapter 3: What Kind of Motor? Chapter 4: Motor Choice Chap…

talesontwowheels.com

 

[Potato011]

Why are you changing out your rims?

From the link below:

"Worth noting: The stock Mongoose wheels never let me down and never took so much as a shimmy; always staying true."

Mongoose Envoy – Chapter 6 (Odds & Ends)

Introduction: The Mongoose Envoy Project Chapter 1: The Raised Rear Deck Chapter 2: Better Brakes Chapter 3: What Kind of Motor? Chapter 4: Motor Choice Chap…

talesontwowheels.com

I followed this guys post when constructing this bike. Great guide. However, he swapped out his rims immediately whereas I've been riding on them for 3 years. Here's what happened a few weeks back. I momentarily swerved into the road but luckily no cars. Ig the limit of the stock rims is 3 years of offroad use. Very respectable for the price.

 

[Potato011]

Hmmm yeah I didn't think about that, I thought if it can manage the disc brakes it can manage the regen braking, but I guess the extra weight is the issue? Not an expert in the whole force calculations and I'm already running bigger rotors than my fork and frame are specced for (203mm, specced for 180mm). But I hope the MT5s will be adequate for me, total weight is not as heavy as yours at about 115kg (250lbs) total including myself.

never ridden a 1kw hub so the deceleration force is all speculation. I've already got enough weight on the front with the front panniers so the back is more suitable for my needs.

 

[99zip99]

What battery do you have as your BMS must allow you to regen at how many watts ? What voltage ? What controller ? This is what determines the amount of region you're going to demand plus regen is heat for a motor

 

[Potato011]

What battery do you have as your BMS must allow you to regen at how many watts ? What voltage ? What controller ? This is what determines the amount of region you're going to demand plus regen is heat for a motor

em3ev li ion 52v 11.6ah with common port bms. The rep said it can take in around 10-15A of power. I got another 52v 25ah pack with a larger common port bms. the controller will be a flipsky 75200 vesc.

 

[gromike]

What is the Mongoose Envoy's cargo and rider weight capacity? I can't find it listed on their website, though I did see that the forks are steel. Couldn't find the bikes weight either.