Ditto what Jagman says. I desperately wanted to do this, but was already overextended for this summer. Please offer this again!
Watched the power up on the bench, but I missed the test run in the parking lot. Dammit!
Looking good!
@Brandon_Green Is this with the plastic coupler?
Yeah the plastic coupler is working great, we measured 30 foot pounds at the drive axle using the digital torque gauge (through the clutch slippage), at the 4.75 to 1 reduction that means there was at least 6 foot pounds going through the coupler with no problem
That looked dangerous as hell…hehehehe
We ran a number of very successful tests and gained a lot good info. Had a ridiculous/insane amount of fun in the process. Improving on the fly w/what’s available. Enjoy the picts.
Resolving minor alignment issues.
Held together w/clamps.
This could get interesting…
Final adjustments and checks before the launch.
How do I ride/stay on this thing!?
Hold on…
Surfing the pallet jack kart.
More clamps to adjust/retain chain tension and a seat for the driver.
Wind in the hair…oh yaaa!
After spending way too much time machining on $5 wheels, we can now bolt them directly to standard american bolt pattern gokart hubs (3 holes on 2.5" diameter, but 2.56" diameter seemed to work better for the hubs we have). Of course no sane person would attempt to use non speed rated hand dolly wheels on a 30 mph gokart, but it has been done before in the power racing series, we shall see what happens…
Them guys are some crazy pallet jack drivers!
So turns out we have not gone down the cheapest path and will spend about double what we wanted to in order to afford 2 karts. I just put together the bill of materials so far, and we probably have another hundred to go at least for the chassis materials. A lot of the mechanical parts could have been sourced cheaper, but I went with what was the quickest and easiest to find (defaulting to amazon). But in the end we will have a unique completely custom built wooden brushless electric kart.
So far we have spent $1,148.72, not including shipping / tax, charger, powersupply, discharge box, (The ESC was donated, so we have actually spent 200 less than that, thanks @David_Walker !)
~700 for motor, batteries, controller, wire, switches
~400 for mechanical parts (shafts, wheels, sprockets, bearings, hubs, spindle)
Brandon,
If you only spent double was was planned for a kick ass result as seen in the videos, I am still impressed all to hell by the efforts of everyone involved.
Great documentation of the process, BTW. This is newsworthy and original material. Now if you can “bulletproof” it for Burning Man and add a flamethrower, you are galactically good to go.
Which gives me an idea for a new topic… but let me think about it first.
JAG “Kermit The Frog Reporting Live From DMS” MAN
It’s an electric kart - tesla coil or something thematically appropriate…
I just Googled ‘Space Kart’ to see what came up, and this image was the 1st on the list…
I started working on the next test mule, In addition to having 4 actual wheels, we will be evaluating just how strong are wood screws? Here it is about half done
There are just 3 screws holding the front spindle on to some sandwhiched 2x4s (which are each just screwed into each other), it at least didn’t immediately splinter when I stood on it
Pretty sure you’re now qualified for frame production on Morgan Motorcars…
Is the front fork getting flipped, so you can drop the handlebars nice’n’low for a low CG of rider?
So that turned out to be the case, within 30 seconds of around 1/3 throttle the motor fried and I saw a small puff of smoke, then we kept the system energized and tried the throttle again to see what was going on and blew up the ESC. Then we plugged in the spare ESC without diagnosing the issue and suprise, that blew up also.
The cheap electric goal is out the window anyway, so I’m going with awesome electric, and purchased an off the shelf 8hp brushed motor kit to put on the kart, so we can try again next saturday. The equivalent brushless kit would be double the cost, and efficiency and longevity aren’t big requirements for this use case.
Awesome. Do you have a link to that 8hp motor kit you ordered? I’m curious for my own projects.
And most importantly, is the 3d printed coupler going to be used…
breath bated…
It’s the Motoenergy ME0708, apparently it’s the equivalent to an etek motor that several famous spinner battlebots used to power their spinners in the past. We will be running at 36 instead of 48 volts (since we are using a 4 10s lipos instead of building a 6 6s lipo pack which would be more cost for same capacity) so it will be less powerful than the max sustained 8hp at 48v. Will be going from a 26 tooth sprocket directly on 7/8" motor output shaft to the 57 tooth main axle sprocket for a 2.2 gear reduction to get our target 1,000 rpm axle speed at top speed of 30mph.
Is anyone familiar with a motor performance curve like the following? It’s not immediately obvious what the horizontal axis means, do they run it up to full speed and then just steadily increase the load?
Will be using an Alltrax AXE 4834 controller, which we can program to limit it to less than its 300 amp max output, seems prudent to start at 50-100 amps.
The voltage stays at ~24v, so I’m guessing they keep voltage steady, vary load, and those are the other numbers gathered at that voltage and load…
But I suck at graphs, so hopefully someone else will chime in…
Those types of graph are usually speed vs. torque, but I admit to being a bit confused by that one.
http://www.vexforum.com/attachment.php?attachmentid=6043&d=1336704320
