I built a 4wd Raceboard. Stooge v5 frame(SN 28), 4x Reacher 7490 motors, and 4x MakerX G300s. Scratch built wiring harness. Sparkly blue colors.
(Is this the most powerful VESC board ever? Math says I should be able to hit 40kW…)
I’ve been working on this project for months. With AVS Riderfest around the corner, I’ve been in a sprint to get this board into raceable condition. Nothing like a deadline to hasten up a project.
Here’s a glorified picture thread instead! Strap in for a long winded one…
The first earliest photos of this project, from @MoeStooge announcing the frame was ready for pickup
It’s somewhere in the realm of 60~70lbs now… way to heavy to do this again.
@MrDrunkenMobster at CarvePDX explaining to me why I should avoid breaking physics with my battery layout
Printed a Blue puck(puck puck bruce shell) and spent way too long sanding
Low-power/Data wiring harness
“All the wires that don’t carry motor power”
If you’re not familiar, the MakerX G300 using a DB25 Connector instead of the JST-PH connectors that you normally see on VESCs. It comes with an adaptor to the standard JST-PH, but that’d be boring
I leveraged my professional experience(spaceship engineer) to fabricate my own harness from scratch. Took way longer then you’d think
I built the harness “from the middle out”, starting with the shielded TSP wire running from the front to rear of the board, and working my way outward. This was taken in the middle of the process before I started adding on the connectors and end terminations, after I got the TSP wires cut and the required single-conductor wires spliced onto the end;
A couple days later, after finishing the terminating with connectors. There’s still a couple left unterminated, that I terminated after it was installed in the board and I know how long I want them to be.
Terminating into a DB25 consists of crimping on a pin to a wire, then inserting this crimped pin to the housing. (Mango Pepsi slaps, btw)
When finished, you put a “backshell” onto the connector to protect the rear of the connector and provide strain relief. I could only find one 90 degree backshell that had the low profile that I needed, seen below
But alas! A problem.
The face of the DB25 connector sits flush with the G300 when fully seated, but the backshell I bought has little tabs that stick out the front face of the connector
So I designed a custom backshell
Nothing special here, nothing ya’ll haven’t seen before on a 3-link setup.
Thanks Jack @HAIRYMANJACK for your help with this.
Mounting the Rear G300s
“The easy side”
The v5 has a spot in the rear for exactly for this purpose, and the G300 just barely fits (Notice the ~5mm of clearance of the terminal block on the left)
The G300’s are much larger then the Mamba XLX2’s that the v5 was designed for… the bottom mounting holes are floating in midair.
Easy fix, just a custom bracket with threaded inserts (it was like 2am and I forgot to get a beauty shot of the bracket with the inserts)
Mounting the Front G300s
“The hard side”
There’s no convenient spot to mount them like the rear, and the belly pan isn’t large enough.
Before I bought everything for the board, the only idea I had was a 5 minutes tinkercad sketch
I live a couple miles down the road from an Industrial metals supply, so I went there to see what they had that could make this possible.
I found exactly what I wanted, but they only sold it in 10 foot lengths.
I ended up riding home with a 10ft piece of steel.
I 3D printed the profile of the steel channel that I bought, so I could easily cut, drill, and manipulate it to find a shape that would clear the 3-links, without taking up too much deck space.
Now to duplicate the plastic parts with the metal
insert grinder montage
The bends weren’t very 90 degree’s from IMS, so I made a quick and dirty metal break to fix that. (before and after)
Now, holes. This took a lot of time, as it was a lot of mounting and re-mounting.
I put tape on the deck, and sketched out the location of everything before I drilled a single hole.
Informal shake test
Shoutout to @janpom for promptly providing a 3D model for the unreleased Megan. It became a structural element on my board. Can’t wait to have a display there!
Paint to match the powder coat!
Interesting tidbit; I used this same paint a couple years ago on a rocket I built (That project is a story for another time)
Compression does not like the sparkles
Drilling a 1" holes in the deck to pass cables through.
Doing this was my least favorite part of this whole build, as it had to be above the center tube of the frame. A little too far, and I’d chip my pretty paint.
It’ll work! Still needs to be wired.
High power wiring
“The wires that DO carry motor power”
Pretty straightforward, just took a lot of time. I used some high-strand count 6 ga wire. I might be pulling 500A though this wire, so better overkill then underkill. nbd, this stuff is as flexible as rope.
The batteries were given AS150 connectors, everything else was given spade terminals. The terminals on the G300’s were treated as terminal blocks, which had the wonderful benefit that I didn’t need to splice any 6 ga (thank god)
The High power wires that went front to rear were routed on the opposite side of the frame from the low power harness, to help avoid EMI noise issues.
The batteries were secured with double sided Gorilla tape
Many hours of cable management and wire tying later, every wire is secured to the frame.
Here’s the money shot:
With thousands of dollars of electronics connected and homebuilt wiring, I was a little stressed. After pacing for an hour trying to figure out what I could possible be missing, I powered on the board.
Connect to bluetooth, and YEEEEESSSSSSSS. IT WORKS. FIRST TRY. ASANFDJKSSA
An hour or so of vesc programming later, Wheels spinning!
A little griptape, and it’s ready to ride.
And that’s the end (for now)!
Thanks for making it all way through.
This is definitely still an ongoing project. Did a small bit of shakedown riding tonight before my batteries died, and I’m already in love.
Right now I’ve only got the motor amps at 100A per motor. I’ll be increasing it as I get used to the board, as well as rear-biasing the power and forward-biasing the brakes. I should be able to put 160A through each reacher 7490’s with ease, so I’ve got LOTS of headroom before I start being limited by my hardware
There’s a lot more I plan on doing with this board, like a charging harness and power button, so I’ll be updating this thread as that stuff happens.
But, it’s raceable enough! If you’re going to AVS Riderfest, I’ll see you there