Battery connections for serial to parallel are done, VESCs powered up and configured for master/slave mode over CANBUS, motors with sensors are connected, detected and setup, and Winning controller is working, and spinning the motors nicely!
All that is left is to stick everything to the board somehow. I’m so eager to get going that it’ll be all velcro and duct tape to start with. I’m so super excited, even just getting the motors spinning finally was an awesome moment.
I do have one concern - your motor mounts. Considering they are so long, are you going to put some sort of bracing between them so they don’t flex?
To fix this, I reckon you could get away with a length of all thread bolt between the middle of your mounts to keep them 90 degrees to the rear axle, secured with nuts like shown in the diagram below. Will probably need to locktite the nuts.
I agree with @baxter. Add a long bolt or grid style plate will to hold either side parrellel and also give extra support. Other than that I think your setup is pretty rad!
Thanks, I was concerned about the flex, and was thinking about using some brackets and a plate to connect the two, but a threaded rod is a much better idea. I’ll definitely give that a try!
First ride was a huge success! Was super impressed with how it handles gravel, both up and down fairly steep gradients.
I just had a couple of failures. I had hot glued the canbus connectors in place, but one of them was glued in place disconnected already! So that was a quick fix. Then at the end one of my batteries fell off, so I can say that Velcro alone is not enough to hold your batteries! Will strap em in for next time.
So, really good fun, still lots to learn and tweaks to make, but I’m super stoked.
Definitely on gravel, without the connector initially it was effectively a single motor setup, and one wheel just span in the gravel even with no load.
I went dual for extra torque as well as traction, and it feels like the right choice. We have a steep gravel drive I want to be able to ride up and down.
No belt skipping, though everything was pretty low speed. I didn’t see any issues at all really, but yeah, need to head out and find some more space to push the acceleration/braking a bit more. It was able to accelerate me up a fairly steep hill from near stand still though, so that’s not bad!
These trucks feel super firm, making it hard to turn. Not sure if that’s just me expecting to be able to carve it up like a surf board or perhaps something particular to mountainboard trucks. I’ve ordered some of the softer yellow shock blocks to mellow them out a bit, hopefully that helps loosen up the turns.
I guess it’s also possible I need to mount the trucks to the board at more of an angle.
Thanks man! Yeah, hoping that this will be of some help for some people, there haven’t been all that many non-mountainboard builds aiming for AT, so it seems worth sharing.
I just remembered that the Matrix trucks have adjustment screws, so gave them a twist to reduce the stiffness a bunch, sweet! Looking forward to giving that a go tomorrow.
A couple more pics, I’ve added a strap for the batteries, took the buckle off a quadcopter battery velcro strap, and secured it and the other side with some bits of bracket I got at the hardware store and bent into shape:
And finally a tiny little 3 second clip of my first ride looking all uncoordinated and slow. The kids love it, and I feel confident enough that it won’t fire off at them, but I think it will be quite a while before I trust it enough for them to try riding.
Another option (that i’ve used) is to secure the velcro strap under the sticky velcro pad the batteries secure to. I’d also recommend the uber strong velcro (3m Dual lock is my preferred) vs the fuzzy kind which just can’t hold as well.
Here’s a decent’ish picture of the smaller velcro straps as backup to the dual lock velcro under batteries:
Cool thanks I did think of the under the sticky Velcro thing, but didn’t have any straps long enough. I think I will order some of that 3M stuff, looks like quality, thanks.
You have the exact same batteries, how are you finding them? What sort of range are you getting?
Cool - glad to steer you towards another solution that may work for you. You are obviously figuring it out on your own! Necessity is the mother of invention!
Range on those - tough to say since my GF rides it 95% of the time. And she goes about 8mph tops… So i run mine down doing circles (or laps) around her and she’s always got most left… After i re-gear (12 or 15mm wide) i’ll do a distance run and let you know. It won’t even be close since you are using those big ass AT wheels though…
I’d guestimate on her setup the usual 10Wh = 1km. So (V x AH =Wh) 29.6v x 8Ah = 236.8Ah/10 = 23.7km/14.7mi
It’s a single motor 63mm 200kv - xx/36t gear (not sure of motor gear - been a over a year). on 83mm fly clones. She loves it and doesn’t want me to change it at all. I’m still going to. So i can ride it and not skip (on 9mm belt now w/ printed wheel gear).
Took it to the park today, had a go around some grassy fields and concrete paths. Was good fun but unfortunately didn’t last long, as I’d loosened the grub screws too much and the shock blocks were falling out! Doh!
Then fixed that and went up and down my terribly potholed and corrugated gravel drive. Not the best place to learn. Found it easier going up than down, as I could stop without the wheels sliding out.
So the 2x 9mm wide XL 5.08mm pitch belts have never skipped, that worked out great
Also, I haven’t yet added the threaded rod to connect the mounts, and I’m not sure if it’s needed. The mounts definitely flex, but that feels OK somehow. I think it makes the drive train a bit more forgiving of things like my slightly off center motor pulley holes.
This is feeling like a great success. Looking forward to the softer shocks so I can turn easier, but this is pretty much exceeding all my expectations.
Nah, I don’t really see the point. Those Lipos are pretty robust, and the ESCs are relatively protected from dust/splashes with the heat shrink. Should be sweet!
I did think of the under the sticky Velcro thing, but didn’t have any straps long enough. I think I will order some of that 3M stuff, looks like quality, thanks.