learn as you go

deacon · #1 (**permalink**) 06-23-2009, 06:11 PM

Yes this is a thread about learning as you go. I'm not an electrical engineer or anything even close so I learn from my mistakes and from my successes if there ever are any.

Today I took the new Pat out for a ride. It didn't seem quite right so after the first ride that got me less than two miles and much less speed than I remembered from the first time I rode it, I checked and found the chain too tight. Who would have thought that the chain tension would make that much difference.

I charged the batteries and took it out again. I got two miles with the motor still running but running very slowly. However I ran the bike wide open the whole time. I wanted to see how fast it would go. I wasn't worried about range at all.

Tomorrow I am going to ride it for range. Just enough power to climb the hills and the rest of the time coast and pedal.

One more thing I learned about the two speed part of the bike. Not to use the lower speed except to start it. Since it uses just one of the batteries it pulls it down well below the other one. When one battery goes down it effects the overall performance of the bike.

I am going to have to be very careful how I use that feature. I need to use it on hills when pulling up from a dead stop, but not on flats when pulling off I can pedal it enough to prevent the chain jerk.

I got about two miles running it wide open throttle, so tomorrow I will see how I do with power management. I would expect about 3 miles range.

Also the more powerful motor on this Pat is pulling more from the battery I'm sure.I guess I am going to look at better batteries after all.

Also I think I want to know what is the optimum size motor for an assist bike. I may have over reached with the 450 watt. The 350 had pretty good power and on the 26" mountain bike I had pretty good pedal assist going.

What I need to do is to run the 450 with the two speed control power management tomorrow. then recharge the batteries and hook them to the 350 with controller and throttle and see how that compares. That should tell me a little about two things the motor and or the controller throttle vs two speed switch. Not to mention the different wheel sizes.

I do love a good experiment.

deacon · #2 (**permalink**) 06-24-2009, 08:36 AM

Well test one of the new motor bike is disturbing. The motor went out at the same place two miles. Whether I ran it wide open throttle and just pedaled to keep the speed up or if I goosed it the mileage was pretty close to the same. Now I am running a 7ah battery pack so I expected it to be small but not that small.

Those batteries are charging now. I will put them on a bike with a controller and throttle next. It has a smaller wheel so that might make a difference it also has a smaller motor which might also make a difference. I will let you know what if any difference there is.

I also never expected the pedal assist to be the same as the w.o.t. test. That was the biggest surprise. Maybe the controller and smaller wheel and motor will make a difference.

deacon · #3 (**permalink**) 06-24-2009, 10:56 AM

The bike test is complete the 350 with the small wheel and controller wins the range test but it isn't quite that simple. It never is.

On the hills I had to pedal sooner and harder. The top end speed is significantly lower. But it did get about 35% better range. I honestly do not think the controller had anything to do with it. I ran the bike at wot all the time. It is a bit easier to start but I didn't throttle back any so the mid ranges were really unnecessary.

I would have had to pedal less if the bike had more speed heading into the hills. I am beginning to wonder if the best compromise wouldn't be a 350 watt motor on the 16" wheel.

The speed difference in the two bikes is really significant. I'm pretty sure the range difference is in the motor size and maybe a little in the wheel size. The question is do I really need the speed.

deacon · #4 (**permalink**) 06-24-2009, 12:12 PM

I have one more test in mind. I want to switch the drive wheels. I want to try the bigger wheel on the 350watt motor. I also want to try the 450 motor with the 12" wheel again. That will answer two questions for me. What difference the wheels makes in the speed of the bike and the range of it.

If the 450 gets better range, then the wheel has an effect. If the wheel give me more speed and better on the hill performance then that also is something I need to know. I would love for the 350 with the big wheel to be the best compromise solution.

If that proves to be the case, I can use that configuration for all the pushers I ever need to build.

deacon · #5 (**permalink**) 06-24-2009, 05:35 PM

Well it took all afternoon but I got the bike wheel on the 350 motor. I had to take the controller off. The chain kept jumping off. After half dozen attempts I put the pusher up on blocks and found the problem. The motor wouldn't start at first I checked the controller and never could find the problem. I just took it and the throttle off. It is easier to just run it with an on off switch. I have some three ways on order so I'll put one of them on just to start it in a really bad situation.

I did it once today but I would feel better with it on a three way.

Now for the test results:

Higher speeds on the flats for sure. Better speed to bleed off on the hills means better pulling there. Not quite so much work to keep up on the incline. There seems to be a compromise on the range. It did a little better than the pure 450 with the bike wheel but not as well as it did with the small wheel.

My feeling now is that the bigger motor draws more amps and the range is decreased. But also the bigger wheel causes the motor to draw more amps as well. I think that when I get the 450 set up on the smaller wheel, it will draw about the same as the 350 on the larger wheel and the speed will be about the same as well. Which will give me two bikes
with similar performance.

To get really good performance I would need the bike wheel on a 700 watt motor at least. That would give me terrible range.

deacon · #6 (**permalink**) 06-26-2009, 03:23 PM

I spent the day trouble shooting my chain troubles. Did I ever tell you that I hate chain driven bikes. Anyway its a #25 chain and electric motor of course. The same setup worked on a different bike. I moved it and the troubles began. chain flying off into space. After changing everything a dozen times I finally figured it out. When the motor kicked it it moved slightly. I know I didn't double tie it. I was counting on the floating bracket to hold it. Bad move. Now I have it fixed along with adjusting the front brake cable and tightening the handlebars. I could not get the bars to hold. So I used a little elctrical tape over the locking area. I hope that will be enough to tighten the grip,

I am using a 20" bike, with a 26" suspension fork and a 20" wheel. I had to lower the brake caliper a couple of inches but I think I have it now. Grand daughter's Drama Camp (of all things) ends today with a play, I have to go of course so no more testing till tomorrow.

deacon · #7 (**permalink**) 06-26-2009, 07:32 PM

I did slip in a ride and it looks as thought I was right. The motor did just fine. The chains stayed in place so the bike works good. The small bike is a lot less stable than even the 24in one. I want to continue trying it but I may have to go to the 24 at least. I'm going to keep trying to work with the 20" because it is so much easier for me to get on and off.

By the way the 500 watt pusher trailer with the 16" bike wheel will not let me pedal at all. It is too fast for the coaster wheel to catch up. So I guess it is pretty stable. I might have some more things that need doing to it but it's a pretty good ride. Too bad the bike isnt more stable.

deacon · #8 (**permalink**) 06-27-2009, 04:39 PM

okay I got the 16 bike wheel with welded on scooter sprocket to run last night and it ran really well. It ran so well that I decided to try to weld on the sprocket I got for the motor. That sprocket converts the electric scooter motor to a bicycle sprocket and chain. With it I can use a bike wheel with the sprocket that is on it.

I picked up a rusty old 16" bike to use as a donor but found it was too rusty. The rust had invaded the interior of the rear coaster wheel so I abandoned it. Moved to a twenty inch 6 sprocket rear wheel instead. It is attached to the 24" mountain bike. It looks like a tandem bike without the second seat. In effect that is exactly what it is. The second rider always pedals when called upon.

I haven't had a chance to wire or test it but that is tomorrow's project. The 350 watt motor is what I had handy. It should do the trick. If not I will just have to decide about what wheel motor combo to use next.

deacon · #9 (**permalink**) 06-28-2009, 06:31 PM

Today's learn as you go moment. I rode the 500 watt 16" pusher motor and it just ate up the power. After four miles the 12 ah batteries were drained. The upside of that motor is that it runs so strong that it is impossible for me to catch up to it so that I can pedal assist. It is so good that it runs on it's own up all the test track hills. The downside is the power use. It just eats up the power.

I I have decided that I want a bike that runs farther on the batteries. To do that it has to run slower. I have a 350 watt motor with a bike sprocket married to the scooter sprocket on the motor itself. I am going to buy another 16" wheel tomorrow. I can't just switch the one I have because I married a scooter sprocket to the rear sprocket of that bike wheel.

I need a 16" wheel to get a feeling for what motor to buy next. The 500 watt runs out very strong downhill, actually nice and fast. The 350 did as well if I remember correctly. I am going to run it to see how it does. If it climbs the test hills without help, I will consider going down some more. I think I want a bike that requires some medium pedal assist on the test hills. About 10 to 12 mph on the flats would be just fine with me. I think the 500 watt is going nearly twenty so I can give up a little of that speed.

The 250 hub is better on power drain, but I'm not sure that the pusher wouldn't be volt for volt a better choice. I'm just going to have to check it out. I would like to get it down to 2 ah per mile or even better. That is the next challenge since I have met the challenge of putting together a bike that will climb the hills around here without pedal assist.

So that is the next challenge. How to make the most efficient diy Ebike I possibly can with my limited amount of knowledge.

deacon · #10 (**permalink**) 06-29-2009, 06:46 AM

I bought this rust bucket 16 bike at the thrift store for a dollar. I hoped that the rear wheel could be salvaged. I was wrong of course. The rust had invaded the rear wheel INSIDE. Pretty bad shape. Everything is rust frost so I'm going to trash it. I was going to make a small scooter from it for my grandson but Becky(my wife) vetoed that idea. Heck he is five years old he needs an e-scooter.

So I'm about to trash it when something struck me. The most expensive (by the pound at least) thing I am buying these days is the motor mount. I can cut the rear wheel hangers from the bike and weld them to a flat piece of metal from the hardware store and make my own hang on motor mount. That's one of the buying the one from the scooter store. You buy it, adapt it, then steal the design sorta.... The best inventions are not brand new, just an improvement on someone's idea. So today it's "Mr. Roto zip meets rust bucket" sounds like a bad drive in movie. I wonder if I should make a movie like the great Texas chainsaw massacre and do it with a roto zip. The great North Carolina Roto Zip massacre, sounds like an great idea. Of course getting the victims to stand still long enough might be a problem.