Quad motor setup and general design questions

mlemczyk

mlemczyk

1 µW
Joined
Apr 10, 2015
Messages
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Hi there!

Does anyone have any experience with running a quad-motor longboard setup (dual mounts on each truck)?
I haven't seen any setup like that in my searches?
I would think that:

Pros:
- more traction (All wheel drive!)
- better symmetry/balance/distribution of power?
- less strain on each motor?

Cons:
- higher cost
- more weight
- more parts
- more things that could break

Related to that, is there a particular reason why most motor mount kits place the motors "in-board" (towards the center of the board) as opposed to outboard?
I can see that an outboard setup would protrude outside of the deck (higher risk of damage?), but it would open the possibility of using a dropped deck (with the electronics and batteries mounted between your feet?).
The DIY and Alien mounts both seem to be inboard, does anyone know of any prefabricated kits that allow for outboard mounting?

Thanks in advance for any input and comments, I'm currently doing my research and planning before I start buying parts :D
 
I've been thinking of a quad motor board lately but it's literally just complete overkill. Lol :) You'll need 4 escs in total + a bunch of wires.

More traction but you don't actually need 4WD.

Placing it inboard allows you to have a useable kicktail and/or pop your deck up. I'm currently riding on a Hoopty 34" with no kicktail and I want my kicktail back. Just haven't made a new board yet.

It also does protect your components a bit.

I've thought about putting components in the middle of your foot stance but that's the difference between an MBS and Longboard. One being strapped to the deck and another simply standing on it with grip tape. You could do that and add an enclosure in the center of the board but if your not strapped to the deck it's a bit difficult IMO.

I personally prefer it underneath the board.

LaGrange L1 offers a outbound motor bracket. Not sure if they are still in business though.
 
Traction and balance just aren't an issue, even with only 1 motor. Only reason would be if you wanted to climb a hill that went up 45 degrees =P
 
Thanks for the insight!

Overkill is fun, and I do have some nasty hills around me :D

I personally prefer dropped/downhill boards, so I would love to be able to make an outboard mounted motor - top mounted electronics enclosure board; I guess a hybrid between a longboard and an MBS; low, stable, and still be able to push/foot brake easily if required.

I guess I could still pick up a standalone motor mount ( http://diyelectricskateboard.com/product/welded-motor-mount-63mm-motor ) and get it welded on to make an outboard setup (rotate it 180deg around the truck)?
Maybe I'll put together a rear-dual-drive this way to start with.

Final theoretical question; assuming you do have four independent motors, would you be able to use higher kV motors as the torque required to get you moving/up to speed would be shared by them?
I guess the same question applies for a dual setup? Can you use smaller / higher rpm motors if you use more of them?

Thanks again!
 
Haha funny you mention. A lot of people have been wanting overkill. Guess we'll see some 14S/16S Eboards shortly! lol It's also not bad if you current limit it and it simply just adds more distance/range to the board + the added power on start up is nice too.

You'll want some 195mm trucks too. 195mm Paris Trucks would work nice and you can possibly use 50/63mm motors that are about 65mm in length.

Yes, you can use higher RPM motors if the load is less. However, IMO higher KV isn't always that great and I prefer not to use them. I wouldn't personally use any motors less than 280KV. Even at 280KV I would only use it on a dual motor board unless you actually change your gearing for higher torque.

I've been enjoying the 12S setups and they aren't too bad at $40/each for a 6S 5ah pack. Considering 4S $23 and 5S $32/$35 or so.

If you use 12S, you don't really need a high RPM/KV motor and can use a lower KV motor for more power 200KV and under.
 
You pretty much nailed the major pros and cons.......4 wheel drive is hands down the most fun you can have on an e-board in my opinion. Power delivery, traction, and performance is just insane if you do it all right. I built my first one 2 wheel drive with two SK3 outrunners in the back and it was nice and lightweight but if you want power and performance there is nothing like 4wd. 1WD is bad from my experience unless you are only on flat pavement, otherwise go for two wheel drive for decent traction/performance/reliability or opt for 4wd if you want raw awesomeness.
 
you could go the hubmotor route. that'll get rid of the space that the motors and motor mounts take up.
 
With 4 wheel drive the torque issue with hub motors would be a thing of the past.
I wonder if Vedder could be convinced to make a 4-wheel vesc? It would need 12 fets instead of 3 but he did say the processor has a lot of unused cycles so it could likely drive four motors. I'm imagining a 4-wheel vesc would cost only twice as much as the current 1-wheel one.
Having all wheels running on one esc gives you some cool options for traction control, stability control and ABS too.
 
agraham said:
With 4 wheel drive the torque issue with hub motors would be a thing of the past.
I wonder if Vedder could be convinced to make a 4-wheel vesc? It would need 12 fets instead of 3 but he did say the processor has a lot of unused cycles so it could likely drive four motors. I'm imagining a 4-wheel vesc would cost only twice as much as the current 1-wheel one.
Having all wheels running on one esc gives you some cool options for traction control, stability control and ABS too.
Click to expand...

That's actually not a bad idea for a 4 motor VESC. 4WD Hub Motors would make up for the motors being hub motors as well.

Would be a pretty expensive board though.
 
It's been discussed before but my brain didn't absorb the subject matter concerning...

In a turn, wheels rotate at different speeds. Don't you get steering issues if your going AWD?
 
@melodius that is a good point but it actually improves turning since each wheel is independently controlled so when your loading up one side in a turn outside will travel farther than inside wheel it will just pull more power than the other or vise versa so it manages itself and makes steering feel awesomely grippy. The problems arise if you have a single axle for both wheels with no diff and the wheels are really far apart you will get wheel hop like a 4wd truck with lockers.
 
melodious said:
It's been discussed before but my brain didn't absorb the subject matter concerning...

In a turn, wheels rotate at different speeds. Don't you get steering issues if your going AWD?
Click to expand...

That's exactly the CAN bus protocol Vedder programmed into making the VESC. In short summary for those not engineers or automotive geeks, its automotive technology that allows communication between multiple devices without the need for a central processor like a home computer. Vedder has already implemented it on the VESC and you shouldn't have much of a problem to daisy chain a bunch of VESC if you so wish thought I do not know what the limit is if you wish to do so.
 
If I was going to do this, I would probably still use a separate, central control cpu to interface each of the escs over the CAN bus. Just by adding a gyroscope to the center of the board you could read the angle it's turned at and add a speed multiplier to both the inner and outer esc sets. You could actually set your board up to have incredible characteristics this way just through minor programming changes.
 
Check out Gnarboards - don't need 4 esc's, just one with correct programming on, say, a Kelly controller...lots of torque and little slippage when off road and great for hill climbs/power...
 
scoot-e said:
Check out Gnarboards - don't need 4 esc's, just one with correct programming on, say, a Kelly controller...lots of torque and little slippage when off road and great for hill climbs/power...
Click to expand...
I'm not sure as I cant find detailed specs but it looks like (and sounds like) those motors are brushed DC motors, rather than brushless which is what the majority of people want to ride
 
He has pretty detailed specs on his fb and kickstarter and regular stand alone website, there are several other skateboard projects that are similar too but yes they are brushed motors and chain driven. However, he has hundreds of miles on them without any burnout motor issues and they are very powerful (and cheap) but that is just one style of course - I think the small "RC" style brushless motors are expensive relatively speaking still for high quality ones that won't have the glued magnets melt off mid ride or other issues including bent motor shafts, etc. Plus the electronics are a bit more complicated as well. Check out the belt drive 4wd bajaboards (kickstarter, fb and standalone website) just now available (for over $3,700usd +shipping out of Australia) for reference as well...

http://gnarboards.com/
https://www.facebook.com/Gnarboards
https://www.kickstarter.com/projects/898206173/gnarboards-gnarly-electric-skateboards

https://www.kickstarter.com/projects/bajaboard/bajaboard-electric-skateboard-extreme-makeover
http://www.bajaboard.com.au/
https://www.facebook.com/BajaBoard
 
torqueboards said:
Baja board is 4 escs. Or 2x aps escs.
Click to expand...

Right but it's brushless small rc style motors like he asked about and a 4wd setup that is pretty state of the art among all the boards I've seen available thus far, definitely the tesla of e-skateboards
 
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