Top Speed : 35+ mph
Peak Power: 7000 watts /
Range: 25+ miles
Build cost: £750
A word on power. When cruising at a leisurely 15-20mph you only use around 500 watts on flat terrain, and approx 1000w up a decent gradient. 7000 watts is peak, and although the battery could sustain it it all day long with its active cooling, the motors and escs would get very hot. You only really see huge power consumption when accelerating hard from stationary on a steep gradient. I think the most ive seen is 3000w, so although its nice to have, it really isn’t necessary.
My board is largely 3D printed, always 100% infill. The pulley, enclosures, motor mount and controller are all 3d printed. A combination of PETG and ABS. A full detailed build thread will be added soon. Its very much a function over form design, maximum power, reliability, range and ground clearance are the primary goals.
Motors – Dual SK3 6374 192KV, these were chosen as they are reliable and have a decent power capability.
Hall sensors – DIY setup, externally mounted hall sensors. You can probably get away by them though, the key is to increase you startup boost. https://danielz.uk/hall-sensors/
Pulleys – 15 to 80, 15mm width, 525mm belts, with bearing as idler pulley. HTD 5 profile. Large pulley, designed and created with openscad https://www.thingiverse.com/thing:16627 Small pulley from rs components.
Battery – 12s7p Samsung 30Q, air cooled, no BMS. Verion 1 of the board used 2 x 6s 5000mah lipo, with was fairly powerly but very limited range of 6-8 miles. Visit the dedicated a battery build page https://danielz.uk/18650-battery-build/
Escs – Dual Vesc 4s. Vesc 6 wasnt a think when i started building. Ive added higher voltage lower esr panasonic caps and a tvs diodes . I did add heatsinks but at 12s they really weren’t needed, the enclosure is actively cooled and keeps the temperatures under control https://danielz.uk/vesc-mods/
Controller – GT2B Simple cheap, it took a lot of design work to create a smaller controller. There is a huge potentially dangerous flaw with the receiver which you must sort out to prevent runaway boards. The problem stems from the fact that the gt2b seems to have two fail safes. One for controller disconnects which can be changed, and one for failing to pair which is 1500ms and cant be changed. If these two arent identical, all hell will break lose if you switch on your board and dont pair within 30 secs! The only solution to this is make sure your custom failsafe is 1500ms, you may need to adjust your trims nob on ur controller to get this value. More on this in my post here https://www.electric-skateboard.builders/t/gt2b-failsafe-question/53017/6?u=danielz
Board -Generic RKB, R2dragon. This was the very first thing purchased for £40 locally on ebay.
Wheels – Rockstar PRO aluminium (Poor Quality) These were a pain in the arse with undersized bearing seats. I wouldn’t recommend them, the bearings binded but have since worn in. Balance beads help with vibration
Tyres – Lord i went through some tyres, tampa treads didn’t last 5 minutes. The stock RKBs were out of round. I settled on a very specific variant of this tyre, be careful with the model numbers.
Charger – 750w atx psu, 2 x 250w hobby chargers. I was initially going to make a 2000w charger using PC server PSUs. However i realised it wouldn’t be portable, and im in no hurry home charging. I cannibalized my PC for the PSU. and settles on a 500w multiple charger design. You can simply use a 500w and parallel charge if you wish. Charge time is 2 hours. You need to modify the ATX so it has a minimum load. More about this here….
Buck converter. – I could only find one that accepted the full 12s voltage. However is has substantial rating and has both 5v and 12v rails. I dont use the vesc 5v power supply at all. The 12 rail powers all the fans and will power LED lights for winter.
Fans – Never skimp on fans, they are all Sunon meglevs, quiet and reliable
Bushings – You want double barrel as stiff as you can find for the rear. Do them up nice and tight. My front are super soft.
Vibration dampening – 8x Anti vobration bobbins from RS.
Steering dampening – I need to get round to fitting the steering damper to the rear at some point. To stop the death wobbles after hitting bumps in the road.
vesc settings – https://danielz.uk/vesc-settings/
Telemetry – Before i made my own uart interface I used to use https://play.google.com/store/apps/details?id=ackmaniac.vescmonitor&hl=en_GB