XiongDa Two-Speed Motor

[drsolly]

I've installed the motor to the rim. But when I put it in the front forks, although they were wide enough to take the motor at the axle end, they fouled the motor a few inches further up. It took me a while to realise that this was why the wheel wouldn't turn!

I fixed it by using a screw jack to widen the (steel) forks by a couple of centimeters.

http://blog.drsolly.com/

 

[drsolly]

Today I finished off. Installed the LCD meter/control panel, installed the controller and a throttle and tidied up the wires. Some comments.

First of all, let me say it's very nice, it's really all I hoped.

It is quiet, except at high speed there's a sort of buzz, nothing that sounds bad.

I'm running it from 12s Lipo. At low speed, I get 12mph, and it climbs the very gentle hill I tested it on like it wasn't there. At high speed, with a very slight downhill, it can get to 20 mph. I'm happy with that; this is a 250 watt motor.

The autochange doesn't work very well; I'm not bothered, I wasn't planning to use it anyway. It has trouble deciding to change gear, I think.

When you change gear, there's a delay of maybe a second before you get power again. Since the motor is reversing it's direction of motion, that's not too surprising.

The LCD thing is a bit complicated to learn how to use, but I guess you'd get used to it. It tells you that it's going to give you motor temperature, but it doesn't - as far as I can tell, all it gives you is the outside temperature. I don't really understand that; there's six control wires going into the motor, surely one of those is the temperature sensor? Maybe I haven't understood the LCD thing. It does give you battery voltage, and speed, which are the main two things I want. The voltage is in volts, hurrah, not some arbitrary number of blobs on a blobmeter. You also get an odometer. I plan to add a clock, because I like knowing the time.

Something to watch out for; there's a "walk the bike" mode, which is nice (2.5 mph in low speed, 4mph in high) but if you invoke it while you've got the bike in your garage, you'd better be ready for the bike to start going forward! But as soon as you take your finger off the LCD's control, the bike stops, which is very good.

The wheel does freewheel forward, but there's more resistance than in an unmotored wheel. Not so much that you couldn't pedal the bike, though. There's a lot more resistance if you try to go backwards, but I doubt if that would matter much to most people. You can wheel the bike backwards, it's just not as easy as forward.

 

[1boris]

Drsolly,I would like to know more about hill climbing.Have you done any more hill climbing.Do you get this mechanical sound D8veh had in his motor when climbing steep hills?

 

[drsolly]

So far, I've not heard any bad noises from the motor.

I'm planning to do some hill climbing trials tomorrow.

 

[drsolly]

Also, I've installed a thermometer on the torque arm, so I can keep an eye on the motor's temperature. It won't be as good as an internal thermocouple, but it should tell me if it starts to get really hot, then I can stop and measure the temp of the outside of the motor.

 

[1boris]

please give some feedback when you have done some steep hill climbing

 

[drsolly]

I took the bike out for a test run. It's powered by 12s of Lipo. The summary of my testing, is that it's the bike I plan to take out when I next go out geocaching. Which means I'm happy with it.

In low gear, the top speed was 12mph, in top gear it was 20 on the level. That's pretty good for a 250 watt motor.

I took it to my local steep hill test road. It climbed it at 7 or 8 mph, with only a very slight encouragement of pedalling; most of the hill it could climb without any help.

The voltage display is nice; the watts display is good, but I have my own wattmeter, which revealed that the max amps was 15 (not surprising, that's set by the controller) and the max watts was 750 (which is because I was pulling 50 volts x 15 amps). It's also nice that there's a speedometer. You can choose units of miles or kilometers.

There's 5 levels of PAS; I haven't tried that out as I prefer throttle. There's also a level which is "walking speed", which is about 4mph, and the bike keeps on going as long as you have your finger pressed on the display's button (which means that if it runs away from you, it'll cut power).

The thermometer on the bike display is useless. I think it's displaying the temperature of the air, it certainly isn't showing the motor or controller temperature. My own thermometer (an aquarium thermometer, cost me about a pound) turned out to be excellent. I checked its display with an infra-red thermometer, and by feeling the motor. The axle is hotter than the casing, and it peaked at 36 degrees C, feeling really quite warm (but remember my blood heat is about 40, so not really hot). It might be possible to put a few more amps through the motor.

The autoshift does work; when the speed falls to around 7 or 8, it changes to low gear, and at 12 or so it changes to high. But, obviously, it has no anticipation. When it changes gear, you lose power for about a second. My feeling is that I'll prefer to make my own choice when to be in low and when to be in high, based not only on my current speed, but also on what I can see coming up ahead of me. So I think that for me, the autoshift won't be very useful.

Which means that I could replace the controller with any controller that will let the motor go in reverse at full speed.

Anyone got any recommendations?

 

[drsolly]

I took the bike out again today, mostly on roads. 12s Lipo. I noticed something. At 12 mph in low gear on the level, it's pulling about 250 watts. In high gear at the same speed, it's pulling 500 watts or more. I know that motors are more efficient when they spin faster, does that explain it?

I'm still very happy with this motor.

 

[Deleted member 4366]

When a motor spins it generates voltage which opposes that coming from the battery, so as the speed goes up, the voltage goes down, and therefore the current goes down with it. At 12mph in low gear, the motor is spinning very fast, so the back emf is high enough to cut the current right down. When you change to top gear, the motor spins at half the speed, so the back emf isn't so high, which allows more current to flow.

This is the reason why you get the highest torque when the motor spins slowly, and why you burn out the motor if you stall it.

 

[nabidana]

So I'm going to go with the same approach as drsolly which may or may not work for me with my more limited experience. It appears that my bike has an alloy fork though, which might be a pain and dangerous to stretch, if I understand you correctly - so I am beginning to wonder about selling off the old bike (as d8veh had suggested in another thread) and picking up a donor bike which would work better.

 

[drsolly]

I agree, everything I've read says don't try to spead alloy forks. The xiongda motor does need more width than I expected, though. I had a geared motor before, and that fit fine in the Haro, but the Xiongda needed an extra inch or so. You can look on the xiongda web site and see the dimensions of the motor, and check it on your bike. Or you could try it on the rear wheel. Or you could get the front motor, and if it's too wide, get a secondhand bike off ebay for £20-£30.

If you just get the motor, remember you'll need to put it into a rim with spokes. If you're interested, I can tell you the rim and spokes I used.

What are you going to use for batteries?

 

[nabidana]

I'm going to check the widths and construction of the front fork, and if it's not suitable, I'm going to sell the bike and replace it with one which will work for this.

I would like to know the rim and spokes you used so I can make a start on the process. This could be great fun...

 

[drsolly]

The rim was this:

http://www.ebay.co.uk/itm/BARGAIN-2-X-EXAL-SUPER-LIGHT-SL19-RIMS-559-19-26-MTB-36H-SPOKE-OFFER-NEW-/331241507234?pt=UK_sportsleisure_cycling_bikeparts_SR&var=&hash=item4d1f8849a2

Two rims for £18. I only used one, but I might build another bike, or replace a worn rim.

Spokes were 213mm from http://www.tillercycles.co.uk/, I got the 13/14 Sapim Strong, 36 of them for £34.20 (there were two extras when it arrived, nice).

I also treated myself to a Park Tool spoke key, which is a bit nicer than the El Cheapo spoke tool I've used in the past.

Yes, it is great fun making an ebike, and it's very satisfying riding something you've built. I say built, I mean assembled out of assorted components. You can read my blog on the process.

http://blog.drsolly.com/2014/07/new-motor.html
http://blog.drsolly.com/2014/08/bought-on-ebay.html
http://blog.drsolly.com/2014/08/stuff-arrives.html
http://blog.drsolly.com/2014/08/rebuilding-bike2.html
http://blog.drsolly.com/2014/08/finishing-off-bike2.html
http://blog.drsolly.com/2014/08/testing-bike2.html

 

[nabidana]

Xiongda motor ordered.

Ordering rims and spokes tomorrow. Speaking to a bike shop to replace the front fork on my existing bike with a steel one. Considering these rims. Will order battery next week. Excited!

http://www.ebay.co.uk/itm/MACH1-MONSTRO-26-559-X-19-AERO-PROFILE-DUAL-WALL-ALLOY-BLACK-RIMS-/390906952514?pt=UK_sportsleisure_cycling_bikeparts_SR&hash=item5b03debb42

 

[Deleted member 4366]

I think I've got a set of spokes for one of these rims. They came from Cattsnapper - he was a forum member that did wheels and spokes, but he's stopped now. I must have been his last order:
http://www.ebay.co.uk/itm/PAIR-26-MTB-Mountain-Bike-Bicycle-Disc-V-Brake-Rigida-Alloy-Rims-Wheels-/111181184811?pt=UK_sportsleisure_cycling_bikeparts_SR&hash=item19e2ea3f2b

 

[drsolly]

What battery will you be getting, and what charger?

 

[drsolly]

I went out on the bike with the Xiongda motor today, and had a very good day out, mostly over rough terrain at about 8mph in low gear, but some on tarmac (including an excessively exciting section on the A14 and A1) at up to 18 mph.

I wonder why articulated lorries feel that they have to blast you with their horn as they whoosh by? I know I'm only a bike and I'm only pootling along at 18 mph, but this isn't a motorway, I'm entitled to be here.

I got my revenge by dinging my bell at them.

 

[nabidana]

So I made a few modifications. Have ordered a Ryde Sputnik rim and spokes to fit (same ERD as the rim you ordered, so same spokes ordered!). I have ordered spokes and rim from same place.

Haven't decided on a battery yet - but it will be a pre-packaged job with a BMS and it will be something tidy enough. Any recommendations in that regard?

 

[Deleted member 4366]

I haven't tried one yet, but this is what I'd get, assuming that you have the bottle holder mounting studs in your frame:

http://www.bmsbattery.com/36v/682-bottle-ebike-battery.html

 

[trex]

why do you want to import battery? get the complete 36V 15AH battery kit from Woosh for £315 including interlink next day courier. Samsung 2900mAH cells.
High discharge, full warranty with charger, UK plug etc.
http://wooshbikes.co.uk/?batteries#batkit