So this is my first post here, but not my first build. My previous build was a longboard I bought somewhere for cheap and the goal was to design/build/print/solder almost everything by myself. So the motor mount, the battery case, the gears, the VESC and the battery were made by hand. This was really nice to get in touch with e-boarding, but after a while i was dissatisfied with the board since it was build poorly (good enough to drive, but not maintainable) and the only terrain that was usable was fresh asphalt.
Hence the motivation to start building a mountainboard. But this time… build it properly, make it maintainable and as always, try and keep the cost low. The base for this board is the MBS Colt 90 deck combined with Flipsky trucks, motormounts and two 6354 140kv motors. As can be seen here, all put together next to the old build. The bindings have yet to arrive.
For the VESC modules, I can solder them myself in office. It was difficult to get my hands on some of the chips (global shortage and what not), but in the end they are soldered and tested. I’m still waiting on the internal NTC’s to arrive so they are note completely done yet.
Powering the complete build are 12 Headway 38120HP 8Ah LiFePO4 Cells. They can deliver 120A continuous or 240A in a burst for 30 seconds. They are big and bulky, so the range to size ratio won’t be that good. But i am curious to the behavior of these cells in general, so in the build they go.
The BMS for the battery is a Daly 12s 100A bought from the one and only Aliexpress. It was delivered last week, but I’m waiting on the crimp contacts for the balancing wires so the battery testing has to wait too.
The batteries and BMS are going to be placed inside a simple box with transparent lid. This will catch the eye and allows me to place a current sensor and temperature sensor inside the box that i can check while driving.
The last parts will probably be delivered in the coming week, so stay tuned!
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Interesting design. I’m curious to see how far 8ah takes you. I’ve got a 14s headway pack but with the 10ah blue cells for an ebike build.
Those lifepo4 cells are something else. You probably know this already but top balancing them in parallel at least once before use is a must.
Also it might be worth it to check if the low temp cutoff for that BMS works. I’ve seen youtubers test that function on Daly BMS only to find it sometimes doesnt cut off at low temps.
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Thanks for the heads up! I was planning on placing a voltage meter in the plastic case anyway, but i’ll keep a close eye on it during my first drive.
In office we have an electronic load and other test equipment, so the battery is going to be tested thoroughly before being mounted on the board. However high amperage can only be done on the board so I’m really curious to the peak current of these cells.
I’m just curious, how far can you drive with 14s 10ah on the bike? About 35 to 40 kilometers?
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Havent tried it yet. I’m doing a custom build and its taking forever.
Know the feeling from my previous board, took me over a year and a halve before everything was up and running. I’ll keep this thread updated with results from the batteries!
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So after some delays I finally received all components to get the board built for a first test run. The Battery was build and I monitored it closely during it’s first charge cycle. All seemed to be OK with 5A charge current and the battery didn’t heat up in any way, so that was that.
The last components for the VESC’s also came in the mail and could be completed.
Everything was mounted on the board with tiewraps and a strap. First impression of the build was that it is nothing compared to a simple longboard. This has way more torque, braking power and handles worse. The handling may be due to the springs being too lose, but that is something for later. Besides that it is a thrill to ride and I’m curious to what it’s limits are.
Some numbers that sum up the testbuild:
- Motor Spec: 64A, 140kv
- Battery Spec: 120A discharge, 38.4V nominal
- VESC Motor Config: 64A with -64A braking
- VESC Battery Config: 30A (for each VESC, 60A total)
So far so good. The next thing is to design a case for the VESC’s, improve the wiring and apply some finishing touches.
On a side note, I’m currently using a simple remote that is a bit trigger happy and doesn’t give any feedback or includes safety functions for that matter. So my next project is going to be a remote with built in display that can connect to both VESC’s and read all it’s information. More on that in the future.
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That looks really good. I was looking into a similar build. If you don’t mind me asking, how much did it cost you?
Also, what did you mean when you say it ‘handles worse?’ Are those L-Faster/Flipsky ATB trucks?
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So i’m guesstimating here, but in total the build was (all numbers are in Euro):
- About 300 for the board without electronics (deck, trucks, motor mount, bindings)
- About 100 for the motors and 180 for the VESC’s
- About 200 for the batteries and BMS
- And then some lose stuff like cables, connectors, and case
So in total more than 600 euro. More than I thought it would cost, but yeah… it’s a project right?
These are the Flipsky ATB trucks indeed. I haven’t really taken it around many corners so I can’t judge it yet to be honest, but compared to the longboard the turning radius is very big and the springs feel lose when it gets up to speed (speed wobbles).
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