Electrically-Powered Mountain Board

[Mario]

Unlike my personal helicopter idea, this one is actually gonna materialize (sometime soon, anyway. ).

I am taking a mountain board (like an oversized skateboard, here's a picture: link) and adding an electric motor and batteries for propulsion.

The motor I have already received and is .5HP (about 400 watts) at 24v. It draws 1.7A unloaded at its top speed of 3000rpm. It is brushless and has a built-in motor controller, so all I have to do is apply power and a pot to get it going.

For the battery I am getting a LiFePO4, 10Ah, 24v battery pack. They're lighter than Ni-Mh and cheaper than Li-ion while still having a good power-to-weight ratio.

The mountain board I am getting is used and cost me $35. It is being shipped as you read this.

I will need to learn how to weld for this, so that'll be a fun experience.

And just to prove this isn't all just a bunch of talk, here are some pictures.

I am using a 10A ammeter which will hopefully give me an idea of how much ride time I would have left at that moment. And look cool.
Kinda blurry, but you can see about 1A being drawn from the motor.

The crazy setup I used with some terrible lead-acid batteries for testing.

The meter came from a battery charger and had the needle centered in the middle. I turned it all the way to the bottom and added a new decal.
Before:

After. For some reason, my printer is freaking out and printed blue and pink instead of green and red. 0_o But, it's still fine. (I will explain the LED in a moment.)

I am making a box to hold the connectors, fuse holder and ammeter. I decided to build a key-start system because I had the stuff lying around. Here is the inside of the box with the key disengaged:

Engaged:

Front of the box. The ammeter has a UV LED in it for coolness and to make the needle glow.
Also a green LED for power indication.

IN THE DARK OH YEAH

Here is a nice shot of the motor I'm using:

And here is what will control the movement. An Atari paddle controller. The fire button (taken out in this picture) will have to be held to activate the motor (so it's also a dead man's switch) and the knob will control the throttle. I might add in some kind of spring return on it, but we'll see.

Once I get the board I can measure the tire size and figure out a proper gear ratio to get a top speed of about 15-20 mph.

 

[βeta]

This seems very dangerous. I like it.

 

[bud]

Mountain Boards are AWESOME.


I really like the throttle control idea.

 

[Antome]

Make sure you don't explode something, and you'll be fine .

Having said that, things should explode for good reasons. Bah.

This seems very dangerous. I like it.

 

[Mako321]

Make it turn with external controls too.

 

[ToastBucket]

Also hotglue some cardboard wings on it. Then tack on a particle accelerator. That should give you enough speed to achieve warp speed.

 

[ShockSlayer]

I could build you a mini flamethrower, you could put it on the back, then you'd look like a badass when your moving. Can be activated by a single tact switch or any switch of choice.

SS

 

[Mario]

You guys are all silly.

I should be getting the board soon, but the battery will take 2 months to get here. Stupid Hong-Kong.

 

[Mako321]

I have an idea, have a pressure sensitive button as the paddle button to have variable speed somehow, and have the paddle controller itself turn the thing
Oh, and have a built in seat.

 

[jleemero]

I have an idea, build a scooter instead!

Fix'd.

 

[samjc3]

I have an idea, build a scooter instead!

Fix'd.

Segaes

Man, Jlee, you are slipping.


So, Mario. how much is this massive lifepo4 pack costing you?

 

[jleemero]

Sam, wtf?

Mako DESCRIBED A *Can'tSayThisOnTV*ING SCOOTER.

 

[samjc3]

I know he did. all i am pointing out, is that you forgot to add, "Segaes" at the end of your post. i wasnt contradicting your analysis of the situation.

 

[Mario]

Sam, it costs $251. $40 extra if I wanted it to get here in 7-14 business days, but I'm cheap and can wait, anyway.

I'll build it like normal and just drop in the battery pack when it comes.

 

[Mario]

I stopped being cheap and started being impatient and added the $40 for quick shipping. I got the battery today, pictures later or probably tomorrow. It smells like cigarette smoke for some reason.

EDIT: The guy I was gonna get a board from sent my money back saying his kids broke the board. Guess I'm looking for another board now.

 

[Mako321]

Dang kids and their board breaking shenanigans

 

[Mario]

Got another board, used only three times. It's in great shape and came with brakes. Cost $100. It's a lot of fun to ride, but it gets speed wobbles at about 15 mph. I'll need to ride it more to practice keeping those from occurring.

Ordered a 10-tooth sprocket to fit the motor and a 30-tooth one for the wheel. I'll use the brake pad as a template to cut the holes and then replace the brake pad with the sprocket.

The motor is .5hp. With a 3:1 gear reduction, that's 1.5hp (ideally) and 20mph at 3000 rpm. The weed whacker on my bike is about 1.8 hp and propels me at 30 mph. I think I'll have enough power.

 

[Mako321]

If it wobbles, replace the thing.

 

[Mario]

lolno

Speed wobbles aren't caused by a bad board. It's basically your balancing reflexes that causes it.

It starts by hitting a small bump or something. Let's say it makes you tip backwards and lose your balance. You press on your heels as a natural reflex to keep from falling over. Problem is, this makes the board turn really sharply. To compensate, you lean the other way and now you're imbalanced in the other direction. The cycle repeats until you fly off the board.

You can stop these by keeping your knees and ankles loose and consciously overcoming the balancing reflex. Turning helps too.

Photos, woohoo.

Got these strong-ties at a yard sale for a buck. They might become the motor mount.

Motor and battery with soda can for size reference.

Mountain board:

With me on it:

 

[bud]

My mountain board was wider.

But I never thought to motorize it