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Off-road EV idea... need lots of help

Posted: Apr 10, 2018 2:54 am
by ClodHopper
I want to start by saying this is my first time ever post to a forum, and I have no experience with ev's. Most of the posts I have gone through have looked like a different language...

That being said I have been a fruit-booter for years. Roller-blades, skates, skiing, water skiing. I feel most comfortable with my feet at my sides. I have seen e-blades and and motor blades, but they're all made for road or dirt conditions. I want something to take me up a trail, a mountain side, or rock climbing. Since I can't find anything remotely close, I want to make my own.

I have an idea for a pair of "roller-blades?" "Skates?" Drivin by one wheel each. Designed for off-road, trail, and hiking conditions. My first thought for power was electric bike hubs. Sizes between 16" and 20" rims. After some research I realized I have no idea what to look for.

Basic design.
2 units would attach to your calfs and feet. 1 wheel mounted to the outside of your foot. A back pack would be carried to hold the battery and other components. A handheld (controller?) would contain a break handle, throttle, and display.

My main concern is the side mounted wheels. My weight being held by only one side of the wheel. Is there a high possibility of breaking the hubs? I plan on putting these through rigorous terrain, even rock climbing eventually. What motors / batteries etc. should I be shopping for? I would like to use "fat" tires but I'm concerned how much weight that would add to each foot. I want to be able to hop from rock to rock if possible.

I was going to post in the electric bike section, because of the larger wheels but this sections seemed more appropriate with the lack of a seat or handlebars. Should I post in electric bikes as well?

I apologize if I'm rambling or incoherent, I have been awake well over 24 hours since this idea took root. I made a (prototype? Model?) That I'm going to attempt to attach a picture of, and some simple sketches.

Im open to any idea, or though but please pretend you're speaking to a child about anything electric. Again I apologize for my lack of knowledge but that's what lead my to this site, and for that I'm thankful.


Image
(Cardboard legs and wheels... and my sacrificed boots)

Image
(Salvaged stroller parts simulate suspension...)

Image
(The most basic drawing I could muster)

Re: Off-road EV idea... need lots of help

Posted: Apr 10, 2018 10:31 am
by SlowCo
I'm intrigued but please upload the photo's directly to this forum as PhotoBucket doesn't seem to work. Make sure to resize them to <500kb before uploading.

Re: Off-road EV idea... need lots of help

Posted: Apr 10, 2018 11:36 am
by billvon
ClodHopper wrote:
Apr 10, 2018 2:54 am
My main concern is the side mounted wheels. My weight being held by only one side of the wheel. Is there a high possibility of breaking the hubs?
Nope. Plenty of stub axle designs are way more durable than your tibia. (i.e. your leg will break before the axle.)
I plan on putting these through rigorous terrain, even rock climbing eventually. What motors / batteries etc. should I be shopping for? I would like to use "fat" tires but I'm concerned how much weight that would add to each foot. I want to be able to hop from rock to rock if possible.
You are not going to be able to "hop" much with 16 inch wheels on your feet. Also even a light hub is going to weigh 3-4 lbs. For example, the NSM hub would work, be good for ~500 watts and weigh 6 lbs. I don't know if it's available with a stub axle tho.

Will you want to put the wheels on the inside or outside of your feet?

Some other thoughts -

There are several hubs that will do this for you. You'll need a direct drive hub since you will need both forward and reverse to balance yourself. You will likely also need accelerometers to be able to provide some stability to the system, along with a fairly custom controller. There are plenty of batteries available. Ebikes.ca has some neat modular packs that you can build into a backpack or belt.

Re: Off-road EV idea... need lots of help

Posted: Apr 10, 2018 3:48 pm
by amberwolf
There have been electric skate projects here on ES previously. I don't know if they will do the job you want, but you could look them up (most are in this section) and at least get some ideas.

Unfortunately a simple search doesn't work because too many people use the word "skate" by itself to mean "skateboard", so you'd have to look thru the threads manually.

Example search
https://endless-sphere.com/forums/searc ... mit=Search
so you can see what I mean.

another search for just skates (plural) probably has more relevant stuff
https://endless-sphere.com/forums/searc ... mit=Search
but it likely doesnt' find all of the stuf you could use.

Can't see your pics at all, but if you attach them directly to the post (see Attachments tab when you're posting or editing) then anyone that can read your post can see your pics.

Re: Off-road EV idea... need lots of help

Posted: Apr 10, 2018 5:51 pm
by efMX Trials Electric Freeride
amberwolf wrote:
Apr 10, 2018 3:48 pm
There have been electric skate projects here on ES previously. I don't know if they will do the job you want, but you could look them up (most are in this section) and at least get some ideas.

Unfortunately a simple search doesn't work because too many people use the word "skate" by itself to mean "skateboard", so you'd have to look thru the threads manually.

Example search
https://endless-sphere.com/forums/searc ... mit=Search
so you can see what I mean.

another search for just skates (plural) probably has more relevant stuff
https://endless-sphere.com/forums/searc ... mit=Search
but it likely doesnt' find all of the stuf you could use.

Can't see your pics at all, but if you attach them directly to the post (see Attachments tab when you're posting or editing) then anyone that can read your post can see your pics.
OP could do a google search of the forum then switch to image view for pics of relevance.. also try inline, etc for a search term(s).. not sure why the google search function was removed from the forum with the recent forum upgrade/ update, it was pretty handy and not everyone may know how to do that..

example :

https://www.google.com/search?q=skate+s ... sphere.com

top result :

https://endless-sphere.com/forums/viewtopic.php?t=46503

Re: Off-road EV idea... need lots of help

Posted: Apr 10, 2018 5:55 pm
by spinningmagnets
Image

Image

Re: Off-road EV idea... need lots of help

Posted: Apr 10, 2018 6:40 pm
by ClodHopper
Still learning the functions. This is my attempt to attach the files. Had to compress from 2mb to 500kb for the form... can't rotate for some reason...
20180409_235033.jpg
Sketch
20180409_234937.jpg
Model zoom
20180409_234915.jpg
Model

Re: Off-road EV idea... need lots of help

Posted: Apr 10, 2018 6:48 pm
by ClodHopper
billvon wrote:
Apr 10, 2018 11:36 am
ClodHopper wrote:
Apr 10, 2018 2:54 am
My main concern is the side mounted wheels. My weight being held by only one side of the wheel. Is there a high possibility of breaking the hubs?
Nope. Plenty of stub axle designs are way more durable than your tibia. (i.e. your leg will break before the axle.)
I plan on putting these through rigorous terrain, even rock climbing eventually. What motors / batteries etc. should I be shopping for? I would like to use "fat" tires but I'm concerned how much weight that would add to each foot. I want to be able to hop from rock to rock if possible.
You are not going to be able to "hop" much with 16 inch wheels on your feet. Also even a light hub is going to weigh 3-4 lbs. For example, the NSM hub would work, be good for ~500 watts and weigh 6 lbs. I don't know if it's available with a stub axle tho.

Will you want to put the wheels on the inside or outside of your feet?

Some other thoughts -

There are several hubs that will do this for you. You'll need a direct drive hub since you will need both forward and reverse to balance yourself. You will likely also need accelerometers to be able to provide some stability to the system, along with a fairly custom controller. There are plenty of batteries available. Ebikes.ca has some neat modular packs that you can build into a backpack or belt.
I hope the pictures work. My plan is to have the wheel on the outside. My current model is very crude but might work for a base model. In my sketch the boot strap holds the foot an undecided distance above the stub. With the stub attached to "jumping stilts" assembly. To assist with hopping and give suspension when traveling quickly over gravel / uneven terrain. Speed is important to me but torque as well for pushing up hill.

(This was my first quote, I apologize if I messed up)

Re: Off-road EV idea... need lots of help

Posted: Apr 10, 2018 11:43 pm
by billvon
ClodHopper wrote:
Apr 10, 2018 6:48 pm
I hope the pictures work. My plan is to have the wheel on the outside. My current model is very crude but might work for a base model. In my sketch the boot strap holds the foot an undecided distance above the stub. With the stub attached to "jumping stilts" assembly. To assist with hopping and give suspension when traveling quickly over gravel / uneven terrain.
To make that work you are either going to need a brake to keep the wheel stationary for hopping or a VERY good resolver/controller combination (to servo the wheel stationary.)
Speed is important to me but torque as well for pushing up hill.
You'll have to decide what your steepest slope will be (also what the biggest rock you will want to roll over is) and then figure out how much torque you need. Top speed is easier to figure out. Once you know that you can run some numbers to see what kind of a hub you will need.

Re: Off-road EV idea... need lots of help

Posted: Apr 11, 2018 3:49 am
by ClodHopper
billvon wrote:
Apr 10, 2018 11:43 pm
ClodHopper wrote:
Apr 10, 2018 6:48 pm
I hope the pictures work. My plan is to have the wheel on the outside. My current model is very crude but might work for a base model. In my sketch the boot strap holds the foot an undecided distance above the stub. With the stub attached to "jumping stilts" assembly. To assist with hopping and give suspension when traveling quickly over gravel / uneven terrain.
To make that work you are either going to need a brake to keep the wheel stationary for hopping or a VERY good resolver/controller combination (to servo the wheel stationary.)
Speed is important to me but torque as well for pushing up hill.
You'll have to decide what your steepest slope will be (also what the biggest rock you will want to roll over is) and then figure out how much torque you need. Top speed is easier to figure out. Once you know that you can run some numbers to see what kind of a hub you will need.
I think 15 mph would be good. As far as rocks I'm not thinking anything huge mainly what you might find on a trail as far as rolling over. And for steepest slope between 15% and 20% grade to tackle the more difficult climbs.

Am I going to need an electrician or programmer for the controller, battery, and motor set up? Can 2 powered wheels be controlled with one controller? Or even without controller? I was thinking an accelerometer attatched to the dominant leg, boot or boot mount that accelerates when leaned forward and breaks when leaning back. Can that be done to control both wheels?

Re: Off-road EV idea... need lots of help

Posted: Apr 11, 2018 6:26 am
by SlowCo
For the low speed and climbing you'll need a geared hub motor with the clutch disabled/welded. A low rpm (201) Q128 front wheel motor laced in a 16" or 20" rim would probably do the trick. Maybe even a Q100 would do as there will be 2 of them.
https://bmsbattery.com/ebike-kit/301-q1 ... e-kit.html

https://bmsbattery.com/ebike-kit/630-q1 ... e-kit.html

But your idea sure seems an ankle breaker when each wheel will steer another way... :shock:

Re: Off-road EV idea... need lots of help

Posted: Apr 11, 2018 10:16 am
by billvon
ClodHopper wrote:
Apr 11, 2018 3:49 am
I think 15 mph would be good. As far as rocks I'm not thinking anything huge mainly what you might find on a trail as far as rolling over. And for steepest slope between 15% and 20% grade to tackle the more difficult climbs.
Sounds like you want a geared hub without a clutch then. They are not readily available, so you might need to get some machine work done.
Am I going to need an electrician or programmer for the controller, battery, and motor set up?
Depends on how you want to lock the wheels. If you use a mechanical brake it would be a lot simpler.
Can 2 powered wheels be controlled with one controller? Or even without controller?
No and no. Pretty much every hub out there needs a controller.
I was thinking an accelerometer attatched to the dominant leg, boot or boot mount that accelerates when leaned forward and breaks when leaning back. Can that be done to control both wheels?
Yes. You'll need a little custom hardware to do that.

Re: Off-road EV idea... need lots of help

Posted: Apr 16, 2018 9:13 am
by Vanarian
Hi, this is a nice project (and a bit complicated one if I may) !

I'm hooked into e-inlines so I got you there :lol: Off-road with inlines or similar makes corner a bit difficult when you got your wheels in the gravel / rocks / dirt / grass. There's also question of how much weight you'll be able to cary on your legs.

You might want to limit yourself to 4Kg total / leg absolute max if possible, because past 3kg it is already heavy and tiresome to handle.

May I suggest that you salvage the electronics and motors from a Segway or a sturdy Hoverboard first ? You could try to build from there and not worry about the electronics themselves. This or a pair of unicycles (solowheel) which will be kinda "attached" to your boots. You might need to add front and rear wheels on both for balancing safety (and limit the front and rear angles of inclination).

This should allow you to experiment quickly on the terrain and improve from there (motors choice, wheels size, etc).

Do you have more pictures ?