Test of high performance jury rig-impressive results.

[creativeadapter1990]

My test ebike has gone thru three major iterations.
It serves as a test bed and as my means of transportation.

Take 3:
The Bike
Frame: Chinese rigid diamond frame steel mountain bike, no front shocks, cheap rim brakes, freebee, relative got it at a yardsale and didn't want it so gave it to me.
Controller: Infineon 12 mosfet board, professionally modded, plugin cycle analyst compatible, solid copper bus bars, 12 x AOT 460 mosfets, toggle on off switch, Anerson Powerpole connectors.
Motor: Huge @$$ Chinese geared rear hub motor presently running 48 volts.

Results:
Handling actually improved greatly with the added weight of the battery bank and motor.
It loves to lean in tight turns and responds wonderfully but with a slight delay to conscious countersteering, in this respect it is more like a motorcycle than most other stuff I have ridden.
Off road ability is ok, confirmed by zipping around Lowell South Common. Works well but will stalls on 60% slope of the retaining embankment next to summer street.

Very fast.
My personal top speed has yet to be measured but my electrical engineering prof visually guesstimated me at 30 mph.
I never came near full speed, a small parking lot with sidewalks full of pedestrians at the end.
At actual full speed: "a little more and you could of caught up to me on my yamaha", Jason Thibodeau, speaking of his gas powered cvt equipped bike.

The above results were early tries on 36 volts with a horrible 25 amp controller. The new setup, also interim, is much faster and more powerful.

Range:
Not yet precisely measured.
A friend of mine has motorcycle with a very similar capacity battery, and a motor almost twice the wattage of mine, pushes his motor very hard, and he very easily gets 40+ miles per charge.
Once spent over an hour and a half riding around my (hilly) hometown of bedford MA mostly at or near full speed doing numerous errands. The same day I went to Lowell by state highway 3A, a bit over 10 miles, then wandered around Lowell (at speed in the lovely lowell traffic) for a good 20+ minutes, stayed in lowell overnight the next day went to north chelmsford via route 110 (another 10 miles), and attempted to go back to bedford via 3A again, finally running out of battery stopping within walking (and walking the motorbike) distance of home.
All of this was on a single charge because I have only one charger, a Mastech stationary industrial charger that doesn't fit on my bike.

One nice battery:
The battery was recharged overnight and seems good as new since.
The battery pack is not a featherweight but is under 24 kg, considering the hungry motor and driving habits not actually all that bad for the range imho.
Family members unacquainted with electric vehicles complained about me spending too much on the battery.
The thing was on sale for $230 !

Problems:
Wire losses are atrocious and the smallest cable I am using is 600 V 50A 250 degree rated. Once after less than 10 minutes of riding my leg touched a bit of the main wire briefly and at first thought I was stung by a bee or wasp. The preexisting cable coming out of the motor is thinner than many sub 500 w motors use and there isn't room for thicker to enter the motor because the designer is an imbecile. This is why the current electricals are TEMPORARY.

Consumer grade bicycle rim brakes really aren't meant for this sort of service and the frame has nowhere to mount disc brakes.
The brakes broke off from metal fatigue in two separate incidents, both at low speed, one at about 15 km/h. Rare enough nonstandard 3 separate bike shops didn't have it and would take over 2 weeks to get and cost as much as a big box store bicycle. Just my luck.
The present homemade battery housing is lightweight but very ugly and moves about unacceptably.

The next bike will keep the same battery and controller but use a new frame and motor, wiring will be redone from square one and the new vehicle will be used for a UMass Lowell study.

 

[amberwolf]

Handling actually improved greatly with the added weight of the battery bank and motor.

Where is the battery?

Wire losses are atrocious and the smallest cable I am using is 600 V 50A 250 degree rated. Once after less than 10 minutes of riding my leg touched a bit of the main wire briefly and at first thought I was stung by a bee or wasp.

Battery wiring should never get hot if it is large enough gauge. Phase wiring for the motor can be required to carry much higher currents, and so should generally be even larger. So it seems like you are using far too small a gauge wire. What gauge is it for battery, and what gauge for phase?

The preexisting cable coming out of the motor is thinner than many sub 500 w motors use and there isn't room for thicker to enter the motor because the designer is an imbecile. This is why the current electricals are TEMPORARY.

But you can always put higher gauge wire right up to the axle end, at the least.

However, most often if things are getting that hot, it's drawing too much current becuase it is not setup optimally--gearing (motor "winding type" or wheel size, for hubmotors) could be too tall for the uses you have for it. Not every hubmotor is the same, and just because it is large doesn't mean it is correctly set up for your use, just that it might be capable of dissipating more heat before it melts down.

Consumer grade bicycle rim brakes really aren't meant for this sort of service and the frame has nowhere to mount disc brakes.

There's a bunch of threads and posts about disc vs rim. What it boils down to is that you can spend less than $50 (probably less than $20) per wheel for good rim brakes that are very adequate even for stupidly heavy bikes like my CrazyBike2, or you can spend hundreds of dollars per wheel for good disc brakes that are similarly adequate. If you go cheap on disc brakes you usually get garbage, or at best poor results.

I've got "YUS" disc brake caliper and disc with Shimano lever and generic new cable and sheath that probably cost the same as my low-end Avid rim brake arms/pads with Shimano lever and god-knows-what recycled cable and sheath, and the rim brakes work FAR FAR better--they are both mounted on the same wheel at the same time. I don't even bother using the disc anymore except when the rim is too wet in the extremely rare rains here.

When properly setup, with the right pads and even half-decent arms/levers (of matching types, which is VERY important!), most rim brakes will work just fine for most ebike uses and speeds. From the threads I've read on here and on regular bike forums, if even good rim brakes are not good enough, you might spend more on disc brakes than on the rest of the bike, including electrics, and still only get the same performance out of them (or have other problems that make them just as unusable for a particular situation).

The brakes broke off from metal fatigue in two separate incidents, both at low speed, one at about 15 km/h. Rare enough nonstandard 3 separate bike shops didn't have it and would take over 2 weeks to get and cost as much as a big box store bicycle. Just my luck.

Sounds like pretty crappy department store potmetal brake arms, if they actually broke off--or perhaps not installed properly, causing a wiggle?. Even the crappiest old recycled stuff I have used never broke off, even on my CrazyBike2 under the most ridiculous loads and stuff. Failed to stop me, sure, but never broke off, evne when I'd put them on wrong (whch Ive done a lot of while I learned bicycles).

 

[NeilP]

Pics would be nice :lol: