# Electric Longboard (need some help)



## Braedon (Sep 18, 2012)

Hello all, I am new to this forum, and have been browsing here and a few other sites looking for ideas and solutions to my problems.

I am designing an electric longboard on a budget, and would appreciate any help I can receive on the subject.

I am currently looking the right pair of motors, batteries, and controllers

Due to the budget, I am looking at using a pair of identical drill motors, taken from new drills. Why new if I am on a budget? I can get them at 50-60% off. I am looking at this one or this one if I need more power. My big problem is that I cannot have the motors be over 8cm in length. Does anyone know where I can find the dimensions of the motors inside? I have been searching and have found nothing. 

As for batteries, I believe that I can take apart the drill batteries, find some cells with the same voltage, but higher a higher amp-hour rating, and hook them up the same (cells of battery in series, with the 2 batteries in parallel like the motors). Any corrections here?

And I would like to build a regenerative controller, rather than buying one, but if it absolutely necessary, I will buy one. However, I do not understand how to make a controller regenerative, and how to go about building one. Could I just start with an RC controller and modify it?


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## Ziggythewiz (May 16, 2010)

Have a look at headway cells for great power in a small package.

You'll likely have a very tough time making a drill motor regen. If you can get it to work it sounds like a great way to face plant.


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## Caps18 (Jun 8, 2008)

Yeah, you don't need the regen. Imagine going down a steep hill and your body wants to go down, but the board has it's 'brakes' on.

You will want a foot switch or something to apply power and maybe a second one that if you fall off the board that will stop the wheels.


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## Braedon (Sep 18, 2012)

Ziggythewiz said:


> Have a look at headway cells for great power in a small package.
> 
> You'll likely have a very tough time making a drill motor regen. If you can get it to work it sounds like a great way to face plant.


How expensive/ what are headway cells?


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## Woodsmith (Jun 5, 2008)

I have moved your post to the non road going forum.

Have you thought about using drill batteries as they come?
Convenient lithium packages that can be plugged into the board and charged with the 1 hour quick charger that comes with the drill.

You can put a number of packs in series to get the voltage you want and/or in parallel to get the Ah capacity.

There are some very big drill batteries now.


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## Braedon (Sep 18, 2012)

Woodsmith said:


> I have moved your post to the non road going forum.
> 
> Have you thought about using drill batteries as they come?
> Convenient lithium packages that can be plugged into the board and charged with the 1 hour quick charger that comes with the drill.
> ...


Thank you, I didn't realize that was the subsection to put it in. My plan is to use the batteries that come with the drill until I can afford better ones, but not as is. They come in a case shaped horribly for the bottom of a board. So I will split the case open and build one that will fit better. They won't fit the charger any more, but I'll built an adapter out of the old casing


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## Ziggythewiz (May 16, 2010)

Headways are cyllindrical cells similar to the original drill cells, but have higher capacity and can dish more current. 8-15 ah each at $15-$22.


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## Braedon (Sep 18, 2012)

3 things I still need help with as of now.

1) out of the 2 motors I was looking at, it seems both have a max rpm of 500. one makes 200 in-lb, the other makes 350. So they are rated to 1180 and 2065 watts respectively? They both seem like potential overkill if so, or am I just bad at math and simple formulas? Looks like I only need 1 then!

2) Still designing the rear live axle truck. I think I have it, but I can only fit in 2 bearings, whereas a longboard usually has 4 per truck. Does anyone know if this would be a problem?

3) Still have no idea where to go with the controller. Everything I have found on this site involves large scale (car, etc) application, where I do not believe that I need that. Could I try to find a worn out racing rc car and use the controller in that? I would very much prefer it to use a wireless rather than wired remote


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## ttw (Sep 22, 2012)

I recently had about the same idea and im also struggling finding valuable information.
For now i'm planning to use brushless rc motors but i don't know how to calculate the rpm or power ill need.
I' want it to have good acceleration and just few miles of autonomy (5-7). 
Maybe i should create my own topic too ^^?


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## Ziggythewiz (May 16, 2010)

A good RC controller(s) could definitely work. We used some of those when I did robotics, so they were hauling quite a load.

Have you been over to endless-sphere? Their forum focuses on lighter things like e-bikes so they likely have more applicable experience.


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## ttw (Sep 22, 2012)

Oh i didn't know that one ill take a look
thanks


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## Salty9 (Jul 13, 2009)

Endless Sphere http://endless-sphere.com/forums/index.php?sid=f118e9ce37923b3b7ce2e570468844ae
You will probably find some board builds there.

For what it is worth, I autopsied a 18V Ryobi drill today (dead switch/controller, needed brushes) and would not use a new motor like it for anything I would want to use over a couple of weeks. It is designed not to be repaired but to die early and be thrown away.


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## EVEngineeer (Apr 11, 2012)

Caps18 said:


> Yeah, you don't need the regen. Imagine going down a steep hill and your body wants to go down, but the board has it's 'brakes' on.
> 
> You will want a foot switch or something to apply power and maybe a second one that if you fall off the board that will stop the wheels.




In response to this, check out Sole Skate. It has an automatic brake to stop the board from moving without you on it.


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