Finally here is the buildlog of my 4WD heavy duty offroad monster board.
As always, all 3D-data is available at Thingiverse: Heavy Duty 4WD Offroad Electric Mountainboard by Peter210780 - Thingiverse
This is what I’m talking about:
The current setup is:
Next Redux Deck
MBS Matrix Trucks
MBS F5 Bindings + FX Pro II Heel Straps
4x Mefo Ice Slider 11x4,50-5 on 125mm Gokart rims
4x VESC 4.7 modified with heatsinks, 0,5mOhm shunts, extra TVS diodes and lots of caps
4x c6364 with internal hall sensors
2-stage 8:1 - ISO-04 chain reduction
32W LED headlight
12s30Ah lipo (10Ah+10Ah+10Ah packs)
3D-Printed NRF Hand Controller (VESC NRF Hand Controller - ESK8 Electronics - Electric Skateboard Builders Forum | Learn How to Build your own E-board)
Just the right toy if you want to have fun when you want to go really offroad:
But let’s go back to 2015 when everything started:
I imagine people on mars getting around on these things. Its funny how the board makes those motors look small.
Infected by the eSk8-Virus I wanted to build my own unique board.
When I started this project, the first designs of the VESC were released but not commercially available.
So I had to order the PCBs somewhere in Hong Kong and a bunch of electronic parts from mouser and to assemble my VESCs by myself:
I bought a cheap, used MBS Pro90 board of ebay and some MBS Matrix trucks. Unfortunately the board has only 20 degree tip angle so I had to use angled wedges to get good steering capabilities.
As my intend was to go really off road, the ‘normal’ mountainboard tires seemed too small and I decided to use 10" mini quad tires:
Because I tried to build this beast as light as possible I started with quite small Hobbyking NTM-5060 motors. Of the box they have way too high 270kv so i had to reconnect them to WYE resulting in 155kv. To get the desired 40kmh with those big tires I needed a reduction of 8:1 which was easier to archive with a 2-stage chain reduction held together by laser cut aluminium sheets.
@lrdesigns: It has been called Lunar Rover before… http://www.elektro-skateboard.de/forum/showpost.php?p=34922&postcount=51
To connect 6x 4s5Ah lipos to 12s10Ah I made a power distribution board with included lipo alarms and loop key:
That is what you get if you let your friends ride…
This was the first rideable version in 2015:
Took it to the German eSK8 Championship https://www.esk8b-dtm.de/?language=en but even if the track looks like a desert and the board looks like escaped from Mad Max the smaller boards were better to handle on this course:
Always wear a helmet!!! (at least the guy behind the camera did…)
One of the first improvements was to get rid of those crappy voltage based battery meters. Instead I’m using this coulometer until now without any issues:
It can be programmed to any battery capacity and to different shunt resistors to match almost any setup. It sits together with a bicycle speedometer in a 3d printed case on top of the VESC enclosure:
The next big improvement was to switch to sensored. Therefore I used 3d printed housings for the hall sensors:
The holders sit on the motor holding plate and can be adjusted to the optimal position:
After two sets of tires in maybe 5 months, I had to look for a new type of tires because those mini quad tires are really CRAP:
I tried to find something in a similar size but had no success and had to go for the bigger and heavier Mefo 11-4.5-5 - gocart snow tire:
To fit these tires on my Matrix trucks I had to machine some custom rim adapters out of aluminium:
After this mod the board started looking like a monster:
@Duffman Wanted to comment ‘‘Destroyer of tires’’ … but then I saw the picture with the crappy tire, so yeh, they were probably not of the highest quality… too bad you had to remake the rims for the new tires to fit.
Congrats on the amazing build, You are seriously a fucking legend brother! this is an amazing build! Made my day
Thank you! But this was only the beginning. I have made a lot more optimizations which I will share as soon as I find the time…
its amazing what those little ntm 5060 prop drives can do
Yes, the power output of 4 NTM5060 was already impressive, but if you were drawing high power for a longer time, like riding in snow or loose sand, they got veeery hot.
Later I switched to c6364 motors and beefed up my VESCs. This almost doubled the power output…
Is it possible to show some pictures of your vesc’s after modification?
Luckily (for you) I had to open my VESC enclosure yesterday, because I had some connection issues with one of my hall sensor plugs.
Cable tension relive:
NRF Transceiver & BT Module and 14 ultra low ESR caps:
6mm bullet connectors for the VESCs:
Microswitches to add the possibility to disconnect every single VESC in case of a fault from the CAN bus:
20µF on GVDD, 0,0005 Ohm shunts for up to 240A current measuring ability, NRF extension and BT directly soldered to the PCB:
VESC with heatspreader soldered to the common positive FET connections, 54V TVS diode on top of of the big ceramic cap. Hard to see under the heatspreader:
@Duffman Thanks for those. Your build is a beast.
@Duffman You should estimate the value of your build… im sure it would grab the first places and would be the king of emtb’s
Your capacitor ‘‘booster pack’’ also looks incredible…
So how many micro farads of caps do you have per one vesc?
Jeesus, this beast is the stuff of dreams. I never thought I would want a mountain e-board. After riding one for 5 minutes and seeing your stuff my bank accaunt is going do die (after its alive in the first place )
I’d like to officially cast my vote for @duffman for Build Overkill Of The Year (BOOTY award) in 2017, based on posting date, at least. I know this build is actually much older, but who cares? BEEFCAKE!!
@Okami The total cost of this build was somewhere between 4-5k€. Hard to tell with this constant rebuilding and improving, don’t really want to know exactly…
I have a total of 28x 680µF caps. 7 per VESC, so 4760µF instead of 2040µF. But much more important is that each of them has less then the half esr than the stock caps, in common 5 times better. So hopefully less voltage spikes from switching at high currents.
@Mobutusan BOOTY sounds good
But back to the buildlog, I still have a lot of things to show you in detail:
The first testride with the new big tires was a lot of fun, but they were throwing so much dirt at me that I had to build fenders. Therefore I had the mounting plates cut from 4mm Alu and the fenders from 2mm Alu and bent to shape:
The two parts were riveted together and bolted to the gear housing:
Spray painted and mounted:
Additionally I finally printed the cover pieces for the gear housing: