Dual Hub Motor with Reverse Question?

[Peterbylt]

I am in the design phase of an Electric Rickshaw/Golf cart type vehicle.

Must be able to carry two adults, will mostly be used to run around campgrounds and resorts, an auxiliary vehicle for our RV. Should mostly be flat ground occasional hills, mostly paved roads occasionally hard packed dirt or gravel, top speed 10 – 15 mph.

My design, not yet finalized will allow it to be easily disassembled to fit in an RV storage bay underneath.

Currently my design is to use 2, 48v 1500W 20 inch Fat Tire hub motors on the rear of a trike type vehicle.

Currently looking at these: 48V 1500W 20" Hub Motor

My Question, I have done quite a few searches and have not been able to locate the answer, I would like the Vehicle to have reverse, I see where some of the controllers do reverse, will most hub motors do reverse? and this function is applied by the controller? or does the Hub Motor have to be designed specifically to allow reverse?

In the beginning part of my build I will probably use the controllers that come with the hub motors, but have seen this dual motor controller with the reverse function. Dual Motor controller with reverse. Although this controller has the functions it is not up to the power requirements.

I have quite a bit of experience with and would like to use a 48V 100AH LifePO4 battery pack made up of a BMS and 16 cells like these. LifePO4 100AH Cells

Thank You in advance for any info.

I am pretty new at this, but have already built a Mongoose Mtn Bike with a Bafang BBS02 750 middrive that works really good.


Peter

 

[Epithemeus]

Geared hubs almost certainly won't be able to do reverse. Direct drive hubs almost certainly will be able to do reverse. But not if the controller doesn't support reverse. The controller determines the motor direction.

The motors you linked are not geared so they shouldn't have any issues with reverse. But I see no mention of the controllers supporting reverse so they probably don't. If you're sufficiently techy you might be able to rig up some relays or something to switch the hall signals going to the motor around and get reverse that way. But that's a level up in diy skills.

 

[Chalo]

Those motors won't be happy dragging a heavy cart at 10 mph on 48V if they're configured to push a bicycle at 30 mph on the same voltage. You can cut the voltage in half to get the speed range and efficiency in bounds, but you probably can't double the current to get the same gross power without cooking things.

I think you'll be better off looking at something like a Cyclone 2-4kW shafted gearmotor to drive an axle differential. Then you can use chain reduction to set the road speed without handicapping the motor's output. It's a common configuration for pedicabs, at least in Austin where I am. Pedicabs use a 13 or 14 tooth freewheel on the motor output shaft, but for reversing capability you'd have to use a solid sprocket.

It seems to me that if you're happy with a trike, it would be immensely easier and more reliable to just put a single adequately torquey hub motor on the front wheel.

 

[Peterbylt]

Those motors won't be happy dragging a heavy cart at 10 mph on 48V if they're configured to push a bicycle at 30 mph on the same voltage. You can cut the voltage in half to get the speed range and efficiency in bounds, but you probably can't double the current to get the same gross power without cooking things.

Are you saying that these Hub Motors would have some sort of an issue running at slower speeds?

I am not saying that we would not run at higher speeds if the conditions permit, just most of the time it would be safer to drive slower.

Most of the time would probably be one person using the cart, but two would use it occasionally.

I am not concerned with wasted potential as long as there is enough power to move two people.

Reason I want the Hub motors is in my evolving design it would make it much easier to break it down to fit in the RV's storage bay.

Peter

 

[Chalo]

Are you saying that these Hub Motors would have some sort of an issue running at slower speeds?

The issue is that when you run a fast motor slow, you lose power, torque, and efficiency. You want to use a motor that's configured to run at your design speed, not twice that fast or more.

I just did a two hub motor conversion on a four wheeled parade float. I used 18V batteries and controllers to run the 36V, 20 mph motors at half speed. But I was limited to their usual current limits (therefore torque limits), which is why I used two motors.

Reason I want the Hub motors is in my evolving design it would make it much easier to break it down to fit in the RV's storage bay.

Well, understand that it's always much easier to use one more powerful hub motor than two less powerful ones. Both mechanically and electrically. It probably would give you better options for breakdown and stowage too.

 

[glennb]

It’s going to be a big project with the criteria you’ve provided so far.

Absolutely has to be a tandem? And can’t be single track?

If you could compromise on those two, you could buy a couple of scooters with removable seat posts and folding front ends.

 

[keithwins]

KISS? Strap two wheelchairs together. Eliminate the interior wheels and hub-motor the exterior wheels, while not breaking foldability. I would consider adding rear wheelie wheels if I had any doubt about stability on uneven ground.
Good luck! Let me know if you get it done!

 

[Papa]

Specific voltage hub motors usually come in two flavors, (1) for large diameter wheels (26" and 700c), and (2) for smaller diameter 20" (406mm) wheels. To maintain similar road speeds between the two different sized wheels, the winding and/or internal gearing is usually different. Knowing that...

Last summer I converted a relative's delta trike using 26" MTB 36v EV conversion components. I simply re-laced the larger 26" MTB hub motor into the trike's 20" front rim, then finished mounting the remaining EV components. The re-laced MTB hub motor produced about 16 MPH top speed, and exhibited impressive low speed grunt - perfect for a 200lb senior and 65lb trike - ridden exclussively on MUPS.

If you decide on pursuing hub motors, I would encourage using 26/700c designated motors, instead of 20" designated motors.

 

[keithwins]

Specific voltage hub motors usually come in two flavors, (1) for large diameter wheels (26" and 700c), and (2) for smaller diameter 20" (406mm) wheels. To maintain similar road speeds between the two different sized wheels, the winding and/or internal gearing is usually different. Knowing that...

Last summer I converted a relative's delta trike using 26" MTB 36v EV conversion components. I simply re-laced the larger 26" MTB hub motor into the trike's 20" front rim, then finished mounting the remaining EV components. The re-laced MTB hub motor produced about 16 MPH top speed, and exhibited impressive low speed grunt - perfect for a 200lb senior and 65lb trike - ridden exclussively on MUPS.

If you decide on pursuing hub motors, I would encourage using 26/700c designated motors, instead of 20" designated motors.

My experience of hub motors has been of pretty impressive low-speed power, actually, which is part of why I think this can work.

 

[Papa]

Peter,
To be clear, I'm not suggesting you build organically. Just posting examples. I personally prefer 3 wheels (in 4130), Trikes also lend themself wonderfully to electric drives & future upgrades. Also... why reverse? If an 800 pound Milwaukee Vibrator doesn't need reverse, why should a 75-85 pound EV need one? ... just asking

The DateTrikE goes Electric

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[Chalo]

My experience of hub motors has been of pretty impressive low-speed power, actually, which is part of why I think this can work.

That's entirely dependent on the specifics of the motors. Geared motors are best for that, but don't reverse (except those from Grin Technologies). For low speed power from direct drive hub motors, you need either big amps or slow windings, or both.

In any case, the maximum torque you can get from a given motor is the product of its design and construction-- not volts or amps by themselves. Those you can exchange one for the other, but the motor only has one amount of max torque to give.

 

[Peterbylt]

Guess I will be finding out if those Hub motors will work.

After I registered on AliExpress, I guess I looked at them enough, and they are keeping track, that they sent me an email at a price I couldn’t refuse, downside projected delivery date end of January.

I will be using the controllers that come with the Hub Motors to start with and will determine if reverse is necessary and change controllers or fabricate a reverse if deemed necessary.

I had gone through the thought process of using a single front drive motor or even a single drive on one of the rear tires, the reason for dual rear drive and the Fat Tires is where we live in Florida some of the campgrounds we frequent have quite a bit of sand, I believe multiple wide drive tires would work better in such an environment. Plus I think the two drive motors will be needed for decent performance when two people are on board (one of them (me) oversized) and will make for a fun ride when driving alone.

I choose the 20 inch tires over the 26 for size and the storage capabilities, I also looked at 16 and 10 inch, the 20 inch looked to have the most benefits, size, availability and price wise.

As the plans take shape I will share, some of the goals are to have it at least appear to be a Golfcart and be easy to get on/off.

Papa, I really like the DateTrikE, a lot to take in there, thoughts for a future build, also has a Flintstone esque, reverse built into it. Would definitely serve my purposes, does not have the collapsible abilities I am hoping to achieve.

Thank you everyone for the responses, keep them coming.

Peter

 

[Chalo]

I will be using the controllers that come with the Hub Motors to start with and will determine if reverse is necessary and change controllers or fabricate a reverse if deemed necessary.

If those are gear reduced hub motors, they won't reverse even if driven in reverse. They contain one way clutches that prevent that function.