learn as you go
- Thread starter deacon
- Start date
Way out of my range... I can build my trailer for about fifty at the very most. Pick up a 16 bike for five bucks at a yard sale and couple of pieces of scrap metal and you are there. Course it won't be as purdy... Heck I can buy a real trike for 250
My newest pusher turned out to be a bust. I was using the kid's bike wheel and somehow the bearings were bad. The wheel locked up.
I tried to reuse the sprocket which I had welded to the bike sprocket and it got warped. So the second version wasn't any better than the others. That time the chain wouldn't stay on. So now I have decided to look at friction drive again. This time with an electric motor and a scooter wheel or maybe a lawnmower wheel with a sprocket attached.
I know I promised that I was not going to build a new bike but technically I'm not. I am just repairing the last one. Or I'm still working on the last one.
I tried to reuse the sprocket which I had welded to the bike sprocket and it got warped. So the second version wasn't any better than the others. That time the chain wouldn't stay on. So now I have decided to look at friction drive again. This time with an electric motor and a scooter wheel or maybe a lawnmower wheel with a sprocket attached.
I know I promised that I was not going to build a new bike but technically I'm not. I am just repairing the last one. Or I'm still working on the last one.
I have always pushed out the pin on a bike chain and then reset it when I resized the chain. However I have also spent about a hundred bucks of chain breakers. Two bike shop parks and a half dozen bell. So I have just begun grinding them down and using master links.
I also general turn a junker mountain bike into a single speed. I was doing that today when I used a coaster master link on it. I got some serious chain noise on the first test run. I think I have figured out how to get rid of the noise. I'll probably have to adjust the chain again. If the master link clip faces away from the gear nest it should be okay. I Think the safest way to do it is clip on the outside of the bike. Biggest sprocket in front and match it to the straightest chain run in the rear. If you have a better idea let me know..
I also general turn a junker mountain bike into a single speed. I was doing that today when I used a coaster master link on it. I got some serious chain noise on the first test run. I think I have figured out how to get rid of the noise. I'll probably have to adjust the chain again. If the master link clip faces away from the gear nest it should be okay. I Think the safest way to do it is clip on the outside of the bike. Biggest sprocket in front and match it to the straightest chain run in the rear. If you have a better idea let me know..
Learn as you go does pay off...
I made a friction drive bike complete in one day. Lessons from the old ww bikes and from the pusher made it possible. Most of the developmental work was done. It was just a matter of adapting it. I do have to finish wiring it and finish the trailer for the batteries to test it with but that's all there is left. I could do it tonight but I'm tired.
I made a friction drive bike complete in one day. Lessons from the old ww bikes and from the pusher made it possible. Most of the developmental work was done. It was just a matter of adapting it. I do have to finish wiring it and finish the trailer for the batteries to test it with but that's all there is left. I could do it tonight but I'm tired.
But it looked so good...
The friction drive was just way way too slow. That had to do with me trying to run it with the sprocket from a scooter instead of direct drive from the drive shaft of the motor. Oh well another lesson learned. I had a feeling last night that it was going to run very slowly. Sometimes I hate to be right.
I went from 11 teeth on the motor to 44 teeth on the drive wheel. Probably cut the rpms at least by 75%... I am going to change the whole thing to a ride to the park bike. That's tomorrows project today is family day. I have to shower and play grandpa...
The friction drive was just way way too slow. That had to do with me trying to run it with the sprocket from a scooter instead of direct drive from the drive shaft of the motor. Oh well another lesson learned. I had a feeling last night that it was going to run very slowly. Sometimes I hate to be right.
I went from 11 teeth on the motor to 44 teeth on the drive wheel. Probably cut the rpms at least by 75%... I am going to change the whole thing to a ride to the park bike. That's tomorrows project today is family day. I have to shower and play grandpa...
I have no idea what I did or how long it will work but I have managed to build a really nice little bike. I went back to the pusher design after the friction drive fiasco. I managed to attach a sprocket to the front wheel of a 16 inch kids bike. It doesn't have a freewheel so I expect it to wear the motor out pretty fast. There might be an unexpected advantage but I'll have to check to see. I am told that if you run a brushed motor and the motor turns faster than your demand for power, ie downhill coasting, that the motor becomes a generator. I'm not sure if this controller will allow the current to back flow to the batteries or not.
I am using 1 350 watt motor with a #25 chain drive. I think there are 11 teeth in the motor sprocket and 67 in the wheel sprocket. It isn't as fast as the 44tooth rear sprocket with the 500 watt motor but it is respectable. With the combination I have, it will not allow me to pedal 90% of the time. It has to be a really long or steep hill to wind down slow enough for me to catch up to the bike freewheel.
I put it on a small 20" frame with a suspension front end. It rides good and it pedals good. I have a coaster rear wheel and I like those. I think from now on I will try to use coaster rear wheels when ever I can find one. Actually the old three speed wheels would be good except for the size of the tires.
My one big learning experience this time is to bolt and WELD all the joints.
I am using 1 350 watt motor with a #25 chain drive. I think there are 11 teeth in the motor sprocket and 67 in the wheel sprocket. It isn't as fast as the 44tooth rear sprocket with the 500 watt motor but it is respectable. With the combination I have, it will not allow me to pedal 90% of the time. It has to be a really long or steep hill to wind down slow enough for me to catch up to the bike freewheel.
I put it on a small 20" frame with a suspension front end. It rides good and it pedals good. I have a coaster rear wheel and I like those. I think from now on I will try to use coaster rear wheels when ever I can find one. Actually the old three speed wheels would be good except for the size of the tires.
My one big learning experience this time is to bolt and WELD all the joints.
I have known this for sometime but it is much easier to build it right the first time than try to patch it together. That said seldom do I know the right thing to do till I have done it at least ten times wrong.....
Deacon, may I ask the specifics of what you're running on this build? if not...
What voltage are your motors?
What size batteries (amp-hours), how many and in what configuration(parallel or series) are they?
What size wire are you running, and how long?
What kind of switch or motor controller are you using?
What's the range on your latest configuration?
Let me know...2 miles might be a good or poor range, depending on how many batteries of what size are being used.
What voltage are your motors?
What size batteries (amp-hours), how many and in what configuration(parallel or series) are they?
What size wire are you running, and how long?
What kind of switch or motor controller are you using?
What's the range on your latest configuration?
Let me know...2 miles might be a good or poor range, depending on how many batteries of what size are being used.
Ah the configuration that gets me to the park for my walk(two miles with less than half the battery left) is a pusher trailer with a 16" bicycle wheel and a 67 tooth rear sprocket. It is powered by a 350 watt 24v currie motor. The batteries are (2) 7.5 ah 12 volt in series. I left the house with 13.25v on them and come in with 12.4 volt per battery. They are probably good for another mile, maybe more, but the performance goes down at about that level usually. Ie more and harder pedal assist. The bigger bikes have more ah and bigger motors.
The controller is 24v 350 watts...... The wiring is 14guage with a house type wall switch as the kill switch. Real ghetto stuff...
The controller is 24v 350 watts...... The wiring is 14guage with a house type wall switch as the kill switch. Real ghetto stuff...
Is that 14 gauge solid wire (the kind you put in the walls of your house) or normal (flexible) wire? Low voltage electricity doesn't work well with solid-core wire; it's the same effect as running a noticeably smaller gauge wire. I wouldn't have even thought you might be using household wire if you hadn't mentioned using a light switch as your power switch. For similar reasons, I would think the switch isn't going to be the most efficient, either.
In theory, you're pulling about 15 amps (350w / 24v = 14.583a). Depending on how long the wire is, I'd recommend 12 or better yet, 10 gauge automotive-type(or something similar) wire. The longer the wire, the bigger it should be, so if your switch is at your handlebars and your motor and batteries are at the back of the bike, go for the 10 gauge. Better yet, use an automotive relay, so the wire between the batteries and the motor is only inches long, and use a remote switch to turn the relay on and off. That would be the most efficient way of doing it. You could use a tiny/discreet wire running to the switch then, if aesthetics matter.
There are reasons behind my recommendations(no, really, there is!). Efficiency being one of them. Drawing more current than a given wire can comfortable handle will make the wire hot, and said heat is wasted electricity. The other being that your motor won't get the power it's demanding (especially under load) - the voltage at the motor will be less and therefore so will the amps. Your motor now has to work harder than it should, running less efficiently and wasting more power as heat. More pwoer as heat makes your motor burn out much sooner.
Well, that's the first half of my lecture on electric basics done, now to throw chemistry into the mix. For all I know, I'm wasting my breath and just annoying you and everyone else, so feel free to tell me to shut up if I'm not providing any useful information.
So...batteries. You're running 2x7.5amp-hour, 12-volt batteries. And pulling up to 15 amps out of them. So, in theory, at full draw, they should last half an hour...but they won't last half an hour under that load. They'll last 15 minutes, most likely. The faster you draw said amps out of the battery (lead-acid/SLA at least), the fewer amp-hours you actually get. In other words, the greater the draw, the less efficient the batteries. It's also hard on the batteries, draining them too fast, and they will have a much shorter life span.
In other words, I think the batteries are rather undersized for the job. Not so much because you need twice as many amp-hours but more because you're losing half of said amp-hours to the inefficiency of the batteries. Larger batteries can put out more amps with less efficiency loss. If you switch to 12 amp-hour batteries, you won't get 1.6 times as much range, you'll probably get 2 times or even more. The next size up from that would be optimal, they come in 15/18/20 amp-hour, depending on the manufacturer/quality. And rather than 2 to 2.7 times as far as your current batteries take you, you'd be looking at more like 3 to 4 times the range. And the batteries would have a much longer life span too. Or a second bank of 7.5ah batteries in parallel would have the same effect. (aiming for the batteries to last 1 to 2 hours under full load is an easy way to decide what size batteries to go for)
Sheesh. That was a long way of pointing out that your wiring might be inefficient, and that your batteries are (almost certainly) undersized for the job. I'll shut up now.
In theory, you're pulling about 15 amps (350w / 24v = 14.583a). Depending on how long the wire is, I'd recommend 12 or better yet, 10 gauge automotive-type(or something similar) wire. The longer the wire, the bigger it should be, so if your switch is at your handlebars and your motor and batteries are at the back of the bike, go for the 10 gauge. Better yet, use an automotive relay, so the wire between the batteries and the motor is only inches long, and use a remote switch to turn the relay on and off. That would be the most efficient way of doing it. You could use a tiny/discreet wire running to the switch then, if aesthetics matter.
There are reasons behind my recommendations(no, really, there is!). Efficiency being one of them. Drawing more current than a given wire can comfortable handle will make the wire hot, and said heat is wasted electricity. The other being that your motor won't get the power it's demanding (especially under load) - the voltage at the motor will be less and therefore so will the amps. Your motor now has to work harder than it should, running less efficiently and wasting more power as heat. More pwoer as heat makes your motor burn out much sooner.
Well, that's the first half of my lecture on electric basics done, now to throw chemistry into the mix. For all I know, I'm wasting my breath and just annoying you and everyone else, so feel free to tell me to shut up if I'm not providing any useful information.
So...batteries. You're running 2x7.5amp-hour, 12-volt batteries. And pulling up to 15 amps out of them. So, in theory, at full draw, they should last half an hour...but they won't last half an hour under that load. They'll last 15 minutes, most likely. The faster you draw said amps out of the battery (lead-acid/SLA at least), the fewer amp-hours you actually get. In other words, the greater the draw, the less efficient the batteries. It's also hard on the batteries, draining them too fast, and they will have a much shorter life span.
In other words, I think the batteries are rather undersized for the job. Not so much because you need twice as many amp-hours but more because you're losing half of said amp-hours to the inefficiency of the batteries. Larger batteries can put out more amps with less efficiency loss. If you switch to 12 amp-hour batteries, you won't get 1.6 times as much range, you'll probably get 2 times or even more. The next size up from that would be optimal, they come in 15/18/20 amp-hour, depending on the manufacturer/quality. And rather than 2 to 2.7 times as far as your current batteries take you, you'd be looking at more like 3 to 4 times the range. And the batteries would have a much longer life span too. Or a second bank of 7.5ah batteries in parallel would have the same effect. (aiming for the batteries to last 1 to 2 hours under full load is an easy way to decide what size batteries to go for)
Sheesh. That was a long way of pointing out that your wiring might be inefficient, and that your batteries are (almost certainly) undersized for the job. I'll shut up now.
No I always appreciate the advice. I live in a town called High Point North Carolina. The reason is that its on the west side of the Piedmont plateau. Lots of up and down hill. The bike coasts a lot of that two miles I was talking about.
Wiring: the wire is 14 gauge multi strand wire, heavy duty Lamp cord actually. It only overheated when I ran the motor without a fuse or controller. It might be too small so I'll keep an eye on it. The switch I use is not the 15amp but the twenty amp one. The kind used in heavy duty circuits. I tried the 15amp but they had a tendency to melt together lol... Remember the title of the thread 'learn as you go'. I have been a while now, long enough to have had most of the things you mention happen thereby teaching me the hard way. Not that I don't appreciate the advice I really do.
The seven amp hour batteries were bought to supplement my 12ah batteries to extend the range some in a parallel application. I found that they will hold up for the two mile ride to the park. They may die early as you suggested. I will keep an eye on them.
I do run 12ah on my 500 watt pusher bike. I will also be running them on the hub motor it I can make it work. I have the batteries sitting on the charging table now.
The bike with the 7ah batteries is a small lightweight bike actually a twenty inch bike frame with the 16" pusher trailer. The biggest problem with it right now is that the coaster rear wheel lacks the gearing to allow for early pedal pickup. If I could pick up the pedal earlier on the hills I could take a lot of strain off the motor I think. I have a twenty inch geared rear wheel I will have to consider putting back on there.
Again please feel free to give me any advice you have. I can use all the help I can get. If nothing else I will be prepared when things go wrong.
Wiring: the wire is 14 gauge multi strand wire, heavy duty Lamp cord actually. It only overheated when I ran the motor without a fuse or controller. It might be too small so I'll keep an eye on it. The switch I use is not the 15amp but the twenty amp one. The kind used in heavy duty circuits. I tried the 15amp but they had a tendency to melt together lol... Remember the title of the thread 'learn as you go'. I have been a while now, long enough to have had most of the things you mention happen thereby teaching me the hard way. Not that I don't appreciate the advice I really do.
The seven amp hour batteries were bought to supplement my 12ah batteries to extend the range some in a parallel application. I found that they will hold up for the two mile ride to the park. They may die early as you suggested. I will keep an eye on them.
I do run 12ah on my 500 watt pusher bike. I will also be running them on the hub motor it I can make it work. I have the batteries sitting on the charging table now.
The bike with the 7ah batteries is a small lightweight bike actually a twenty inch bike frame with the 16" pusher trailer. The biggest problem with it right now is that the coaster rear wheel lacks the gearing to allow for early pedal pickup. If I could pick up the pedal earlier on the hills I could take a lot of strain off the motor I think. I have a twenty inch geared rear wheel I will have to consider putting back on there.
Again please feel free to give me any advice you have. I can use all the help I can get. If nothing else I will be prepared when things go wrong.
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Today's experiment was to run the same bike with a 500 watt motor on 24volts and 36volts. Of course there was a difference but how much. It was noticeable for sure but it wasn't enough for me to leave the bike at 36v. Why you ask? because the extra pedaling I did was minimal and very easy to do. In other words, "She weren't no trouble atall."
What I did was to mix and match my batteries. I put two 7ah 12 v and one 12v 12ah battery on the bike. I can configure them either or 24v or 36v with no trouble at all. I figure that is the best of both worlds. If I find a place that I really need 36v I will consider setting it up for 36v... If not I'll leave the 7ah in parallel for the extra range.
Where I do need the 36v is on the 250 watt hub motor. On some of the long hills here I get winded. That should help with it. The new 36v controller should be here this week I hope. I have already put the wheel back on the bike and added a new throttle, I also have the battery trailer finished. I am going to add a lid to it so that I can put a basket on top to carry things. You can never have too much storage space on a bike.
What I did was to mix and match my batteries. I put two 7ah 12 v and one 12v 12ah battery on the bike. I can configure them either or 24v or 36v with no trouble at all. I figure that is the best of both worlds. If I find a place that I really need 36v I will consider setting it up for 36v... If not I'll leave the 7ah in parallel for the extra range.
Where I do need the 36v is on the 250 watt hub motor. On some of the long hills here I get winded. That should help with it. The new 36v controller should be here this week I hope. I have already put the wheel back on the bike and added a new throttle, I also have the battery trailer finished. I am going to add a lid to it so that I can put a basket on top to carry things. You can never have too much storage space on a bike.
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I was having so much trouble with the 350watt on the small bike that I had to park it and go with the 500 watt on the 24" bike today. It works so much better on the ride to the park. I can run the 350 at 36volts on a bigger bike and get pretty close to the same performance. I don't need to do that just now but at least I'm pretty sure I can. I won't have to buy a different setup if the 24" dies. I can just replace components from the smaller bike.
I will soon hopefully have the hub motor up and going as my second bike. I like having a lower power bike as well as the 500 watt pusher. I think pretty much as I did before that a 600 watt 24 or 36 volt hub motor would be a good all around bike. I would personally rather have brushes. I'm not sure that I could find a brushed hub motor these days.
I will soon hopefully have the hub motor up and going as my second bike. I like having a lower power bike as well as the 500 watt pusher. I think pretty much as I did before that a 600 watt 24 or 36 volt hub motor would be a good all around bike. I would personally rather have brushes. I'm not sure that I could find a brushed hub motor these days.
Is that 350 watt motor that you were running at 36 volts originally a 24 volt motor? and if so were yo using a speed controller of some kind?
At the moment I'm not running it at all. I have run my 500 watt at 36 volts with a 24v heavy duty controller from tnc. I just ran it a couple of miles then put it back to 24v.
The 350 I am going to run at 36 next. I am running a cheapo 24v controller on it but I expect it to blow. When it does, I will go with a 36v from tnc. I think I am going to get the 800watt so I can use it on even larger motors should one show up. Things change often in my building.
The 350 I am going to run at 36 next. I am running a cheapo 24v controller on it but I expect it to blow. When it does, I will go with a 36v from tnc. I think I am going to get the 800watt so I can use it on even larger motors should one show up. Things change often in my building.
make sure you know where your reading glass fell before moving the bike being worked on. I just ran over yet another pair. It's a darn good think I know where to get them cheap.
Since I had some time today, I began to rebuild the 350watt pusher. What I did was make a complete unit of the motor and drive wheel. I cut the rails down and made cross bars at the front and rear of the wheel. I also mounted a sorta harp on the bicycle. I have to attach the two pieces together tomorrow. I think it will give me a more secure mount. If it does I will be converting the 500 watt as well. If not it was a good try and I'll just keep trying things till something works.
Okay today I did a sort of almost scientific experiment. I used one 12v 12ah battery plus two 12v 7ah batteries in parallel to make a 24v circuit. I rode the bike about 2 miles more or less then read the battery voltage on each of the three batteries.
first the results... 12v 12ah =12.4 volts................. 12v 7ah 12.9 volts each............
I was more than a little surprised by the difference. I expected it to be a couple of tenths of a volt difference but not that much. all of them started at 13.25v before I left home I did read them to be sure.
Now I realize that I made a 14ah battery with the parallel circuit but still I wouldn't have expected that much difference. It doesn't look like much but percentage wise it is a lot.
first the results... 12v 12ah =12.4 volts................. 12v 7ah 12.9 volts each............
I was more than a little surprised by the difference. I expected it to be a couple of tenths of a volt difference but not that much. all of them started at 13.25v before I left home I did read them to be sure.
Now I realize that I made a 14ah battery with the parallel circuit but still I wouldn't have expected that much difference. It doesn't look like much but percentage wise it is a lot.
