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My second electric bike

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My second electric bike

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Old 04-29-16, 08:00 PM
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Badzilla
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My second homemade electric bike

Please see...
https://www.flickr.com/photos/[email protected]/
or lo-res pictures at bottom of this post.

August 6, 2016

Ordered a Triad CounterMeasure drift trike. Looks like it will make a great land ski. No need to make sprockets or use a chain. Directly driving the 18" front wheel at 450 RPM (no-load) should be a maximum of about 20 mph. I will sell the axle and wheels. So it will become a motor assisted kick scooter. Might use a small rear wheel with a skid in front of it (maybe using very small wheels).

July 13, 2016

Added a picture of the bottom bracket spindle to drill connection (below). It's a simple matter of removing the drill chuck and adding a 1/2 inch 20 TPI nut in place of it (use a spacer on the inside and slice off the excess from the outside). Then connect as shown. The only real work is spinning the socket and using a rotary tool to slice off about 1/4 inch from the drive side of the 1/2 inch drive 3/4 inch socket. That's so the bottom bracket spindle bolt will reach the spindle when stuck in through the socket. Should be a piece of cake to power a drift trike.

July 12, 2016

This looks like an ultra-easy way to motorize a drift trike. On a 20 inch wheel, no need for sprockets with Dewalt's most recent drills (820 UWO at 450 RPM is just over 20 mph). The only sticking point I see is the small amount of space between the fork and the spokes. But if the bracket doesn't fit, surely it can be modified. I'm counting on the bottom bracket spindle to be square tapered like a typical bike. That's how it looks in the manual.

July 2, 2016

It rides like an ultralight motorcycle (at a max 20 mph). The gear case gets hot but I don't know if that's significant. Time will tell. I used a slightly banged up gear case instead of a new one.

Ordered a Dewalt DCD991 kit. The drill is 26% more powerful and shorter than the 995 hammerdrill. The kit includes two 5 amp hour batteries that will increase travel distance to about 20 miles. It will replace the current bike's DCD995 or it will be installed on another bike.

June 10, 2016

Added a bunch of pictures and a description.
Acceleration is good. Top speed is at least 18 mph, 20 would be plenty. Still no clunking when the chain catches up to the wheel speed. I guess that's because of using a derailer as the chain tensioner. When it starts pushing the bike, all I hear is gear noise. Still need to measure miles per amp hour.

May 4, 2016

Pictures have been added. So far, so so. Have taken it around the block a few times, and taken it about 2 miles to and from the store. The DCD995 gearcase makes more noise than the DCD780. It's more powerful and top speed is higher. The gearcase seems to get warm easily. I'm using Park Tool grease in the gearcase. Strangely, there seems to be no slapping/banging against the freewheel pawls when throttle is applied. This time I'm using a derailer for the chain tensioner instead of using a homemade semi-rigid chain tensioner. But I don't understand how that stops the banging when the sprocket catches up to the wheel speed. Maybe it has something to do with the brushless motor. Whatever, if it is as it seems to be, that's great. Still to be determined is top speed, miles per amp hour, and durability.

Original post...

Scroll down [the above-mentioned page] and you will see the "bottom bracket to drill connection". A standard cartridge was used, but the tightening is the same into the socket. Being a bolt instead of a nut doesn't change the method.

That's the most difficult part when designing a cordless drill powered electric bike. The next most difficult part is the bracket for holding and aligning the drill with the bottom bracket connector. This iteration is light years better, assuming it's sturdy enough. It can't be any easier and simpler, using two sturdy pieces of aluminum flatbar with eight holes drilled through it for 1/4 inch bolts. Also, a long mountain bike seat post was used that is 2/10 of a millimeter wider in diameter than the stock seatpost, so that it's a deep and snug fit. That to reinforce the seat tube in case much pressure is needed.

Besides the simplicity, aligning the drill with the bottom bracket is miraculously easy compared to my first underpowered bike that's been running well for ten months. I do expect some wrenching since it's a powerful drill (Dewalt DCD995), and there is a plan B, but time will tell.

The trigger controller also turned out very well. A cheap Shimano shifter can be converted into a simple no-click spooler by taking it apart and removing a plastic piece. The wire connection to the drill trigger is easy. Just connect the cable housing to the trigger button and connect the wire to the side of the drill using a lot of hot melt glue. When the shifter is rotated and the wire is pulled into the cable housing, the cable housing moves the trigger button inwards.

The only difficult part is cutting a 1/2 inch square hole through the 3/8 inch-thick aluminum disk. That for holding the front sprocket to the bottom bracket. I consulted lots of metalworkers for advice on the issue. It's a difficult task without an expensive tool(s). The back of the socket (drill to bottom bracket connector) presses against that 3/8 inch thick aluminum disk, giving it stability. A tool (called a "broach") for cutting a square hole through aluminum cost $200+ (US). Appropriately sized square files are in order. Perhaps they can be used similar to that expensive dedicated tool, or just the way they are normally used to square a hole. This time I used a cheap 1/4 inch square file that crudely got the job done.

I have found that modifying a derailer is not too difficult. I might make a chain tensioner that also provides some spring in the drivetrain. So that power doesn't need to be applied gently. With my current bike, applying power is sort of like the gentleness required in shifting a manual transmission.
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Last edited by Badzilla; 08-06-16 at 07:59 AM. Reason: upgrade
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