4WD Electric Skateboard Questions
I've been researching a whole lot of different ways for me to go about making a gnarly 4wd skateboard.
4WD: 4 x 350-400 watt motors (one on each wheel)
24V system: 2 x 12V SLA 24Ah Batteries (seems to be the best "bang for the buck when it comes to batteries)
35MPH top speed
6-8 mile range
The issue I am running into now is that I can not find the correct motor-controller(s).
I'm looking for a motor controller that offers Variable Regenerative Braking.
The closest thing I have found that is what I am looking for is this:
The only problem w/ the above is that I would need Brushless motors if I wanted to use the 350 watt brushed motors that I can get a killer deal on.
1. Is there a 24V motor controller rated for (50A or 100A continuous) that offers variable regenerative braking for Brushed motors. (Basically I think what I am looking for is the above linked controller but for Brushed motors)
2. Is there an inexpensive 350-400 watt brushless motor that can be direction reversed (2 of the 4 motors would need to spin in the opposite direction) and can also be externally controllable via the above linked controller?
Thanks a bunch for any help. This school project is turning into a nightmare of back and forth research, so any help is appreciated.
I wouldnt get too hung up about regenerative breaking - you really dont get that much back (maybe 2 or 3% and thats on a bike), and it Really wouldnt be worth it on a skateboard.
Brushless motors are great, model plane out-runners can produce in the range of 500w, two of those (not 4) would be enough, and also they run off around 11volts so a 3 cell Lipo can be used which saves loads of weight.
Wow, looks fantasticly made.
And where did you take the photos, it looks like studio quality photography?
So how does it perform, can you make a Youtube video of you demonstrating it!!?
And the big question is Will you now be selling these? Lol!
Awesome video, that kind of action with dust and gravel flying you drift round those coners is something Ive never seen from a skateboard before!
If Visforvoltage had awards I think you ought to get 'innovation of the year' award!
One thing Ive been wondering about ...
Because 2 of the motors must be effectively 'running in Reverse'
Did you have any issues with this?
Many motors have their brushes adjusted with a timing offeset (the brush positions are advanced slightly to take account of inductive delays)- this makes them more efficient in one direction. The downside of this is that they are less efficient in Reverse. Im not sure if your motors were set at midpoint so they were equally fast in both directions?
Yes, maybe these cheaper motors dont come with any 'Offset' and they are equally bi directional.
More expensive motors do come with an offset, you gain about 10% in the forward direction, but lose 10% (in power and top speed) in the reverse.
Maybe someone else can comment on whether the Chinese motors come non-directional as standard?
It would be good for someone else to comment on this thread, Im a little suprised at how few comments this topic has attracted given how exciting this invention is, and with the good video and clear pics etc. ....
Perhaps they're all to busy with their broken Vectix's to watch u burning rubber! Haha!
No cant do it with Brushless motors because the controller uses feedback from the motor (either Hall sensors or back EMF) to phase the supply.
Interesting point parallel vs series.
The controller delivers the volts (lets say full speed 24v) and then the current will be divided in inverse ratios to the resistance of the motors. Faster turning gives more back EMF and equivalence of resistance - so as you point out the slower motors take a bigger share.
Josh i think the skateboard is really cool but i was wondering what motors, batteries and the controller did you use and where you brought as i would like to build something similiar.
Wanting to try something much less ambitious. Was wondering if a brushless motor and controller for a larger RC truck might work? Thought to use a belt drive transmission line as seen in many commercially available skateboards.
The systems I have been looking at seem to have impressive specifications. Controllers capable of handling large currents in tiny form factor. Motors designed to to work in hostile environments. Is there some obvious flaw in my thinking here?
Would really appreciate some input.
where did you buy the batteries?
and where did you get the saw hub cap + wheels