Friday, September 15, 2017

Advanced Ebike Building Tips

List of cool tips and tricks to make a rear-hub MTB ebike as tough as a tank. 

My Ebike: 25kg, 1700 Watts, 1900 W/hr battery, Full Suspension, 26x2.00 Tyres. What a laugh!!!

My home is in a steep gorge with cliffs and crazy mountains climbing high all around. I chose a full suspension bike frame with a lot of battery space, It will take you over most terrains of mountains on boulders, forests and tarmac. here's a guide:

where to get free battery box armor plating?

1/ The Toughest lightest armor, except for carbon fiber, is FR4 standard circuit board plate. It is an oven baked stratified fiberglass sheet, which you get for free in motherboards and everywhere. Once you chisel off the integrated circuits, held by silver flux, using an old chisel, its 2mm thick with flecks of welding through it. Get two ATX PC's that are outpaced by your smartphone. Use them as armor.

2/ It's fine to just put it in a battery box nylon bag, with some armor FR4 layers taped on.

3/ You can find sealed Pre-Preg epoxy pre-impregnated fiber which is stronger than steel called Fiber Fix, you can literally tape up a box shape in 10 minutes. it's a bit expensive. Same as epoxy impregnated carbon fiber, except faster. Use it for the edges of your box and FR4 for the plates. to make a rigid armored battery box.

- What Spokes? get 14g spokes minimum, dip the nipples and ends in sticky stuff like linseed oil to stop them changing place on the wheel.

- Robust Sliding Sheathes? All the cables must run free beside, not under, electric add-ons, else braking and gear cables and derailler hangers wear out faster.

- Regeneration is easy these days. ebrake and proportional regen controller means you can break for 20pc regen and twist throttle to increase regen with brakes engaged, it;'s a 2 pin connector.

- Avoid a poltergeist throttle: I was lost in ravines and cow fields one day, and the motor became stuck at full throttle. I could have landed my head up a cow's butt that day, lucky it wasn't at the traffic lights! Cheap throttles are designed with that in mind, it's a techincal flaw. Don't ride with an uprotected throttle wire. Dremel and polish the exit of the throttle wire sensibly so it is a silouhette of the handlebars, same as a motorbike would be, rather than a kids crawly toy.

- The Steel torque-arm exists on all motor-bikes:  Torque arm is so that the hub-wheel can't fall out even if the bolts get loosened by 1000W of counter-clockwise torque and you are climbing steep hills and even jumping curbs. An aluminium fork is plastic for a 1000W motor axle. To slot in and take off the back wheel off  without undoing a torque arm bolt, the torque-arm axle-slot-length must be long! 3/4+ cm, so when your bike is uside down, you can change the wheel just like a normal bike, but with a 4cm steel recess.Use 5mm of carbon steel torquarm metal for a 1000W motor, and 7mm for a 1500W motor.

- carbon fiber epoxy can fix fatigued welds, if you love your ebike or you are in Karnataka and your garage is in Kentucky. It bonds to aluminium like a boat mooring and it's stronger than steel.

- You can use a Standard Silicone Diode (not LED) in single and parralel to reduce any circuit by .7v, including chargers and lights. i.e. a 5v adapter can be set to 3.3v using two little diodes very safely and then you can run USB map-phone port and any white diodes at cold temps (white leds are from 2.8 to 4v).

- Integrate a 5v converter (DC-DC) and a USB female slot from a thrown out computer, cut around the USB fem slots using a hacksaw, short the two middle USB plug wires as per ISO definition so your phone detects it's on an AC supply, join just the 5v +- wires.

- Buy low temperature solder 500g sn42bi68 alloy for $30, it melts at 130, for soldering large plugs and 1500w cables fast and easy with a small solder iron. it will last a long time.

- leave 20-50 percent extra rating on all your electronics hardware, i.e. a 40A controller lives longer on 30A max.

- How to protect inner tubes? You need a polyethylene shield lining ribbon directly under the tyre and over the tube to reduce punctures by 90%. It handles anything except paths of mowed thorn trees, don't ride on mowed prunus. I found goo filled inner tubes to be unrepairable for pinch and big holes, the goo makes the patches fall off.



- How to chose tyres? semi road flat knobbed 2.0 inch tyres are great for all round MTB ebikes rear wheel, 1.7-1.9 is fine at the front.

- Color animation of hub motor: know 3 phase motor logic: https://www.youtube.com/watch?v=ec0TjyE3Vpo

- How to cool a  hub?
The lighter the hub, the faster it gets too hot, especially at low 36/48 voltages. 72-88V is cooler.

1/ If you go to mountains and arid hot regions, you can keep a flat 0.5mm wire mesh handy, rolled up like a bandanna, which you can wrap around the hub to act simultaneously as a heatsink and/or sponge.

2/ You can thermal adhesive a bandanna of rolled up aluminium mesh (0.5 mm) to the hub between the spokes. Perhaps mix aluminium or copper shavings with vibration proof metal glue.

3/ You can glue aluminium mesh disks to the hub's sides too if you need it cooler.  In future, hubs full of fins and thermal adhesive would be 3x times cool.

4/ For reference, non-conductive thermal adhesive can be mixed up with A/all purpose tile/metal silicone solvent-less glue B/boron nitride C/aluminium oxide, judge rations yourself!



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