Please give me advice on my electric bicycle pusher concept? Drawing included.
March 20, 2011 5:50 PM Subscribe
I would like to build an electric bike pusher. Having never done this before, I'm seeking advice from those who build bikes, know motors, or maybe have built electric bike pushers before (best scenario. Link to my concept after the...
Concept here
My questions and considerations:
- Are geared 24v motors all they are cracked up to be? I see 36v and 48v motors for sale, but that would mean more batteries, more weight, longer stretch for the pusher. I have seen a lot for sale with bicycle chain sprocket attached, but don't know if they are any good.
- Do they make geared motors with clutch or single-direction power? I'd like to be able to pedal if I have to (and potentially save battery life).
- Is a solidly attached pusher going to cause serious problems on corners? FWIW, almost all of my commute is straight quiet highway travel, 15km.
- Thoughts on throttle/controller? I have no idea how to proceed on this portion.
- I intend this to be a welder-less design, with threaded "ready-rod" bolted (and double-nutted) across.
- Wheel for pusher standard 4/5/6 sprocket bicycle wheels (basically, whatever I can scrounge up.
- What's the most reasonable and small 12v battery charger that I could bring along to charge this at work?
Thanks for your advice!
Concept here
My questions and considerations:
- Are geared 24v motors all they are cracked up to be? I see 36v and 48v motors for sale, but that would mean more batteries, more weight, longer stretch for the pusher. I have seen a lot for sale with bicycle chain sprocket attached, but don't know if they are any good.
- Do they make geared motors with clutch or single-direction power? I'd like to be able to pedal if I have to (and potentially save battery life).
- Is a solidly attached pusher going to cause serious problems on corners? FWIW, almost all of my commute is straight quiet highway travel, 15km.
- Thoughts on throttle/controller? I have no idea how to proceed on this portion.
- I intend this to be a welder-less design, with threaded "ready-rod" bolted (and double-nutted) across.
- Wheel for pusher standard 4/5/6 sprocket bicycle wheels (basically, whatever I can scrounge up.
- What's the most reasonable and small 12v battery charger that I could bring along to charge this at work?
Thanks for your advice!
Response by poster: hattifattener: Nope, I'm willing, but am concerned about cost. Another area I don't know much about, I'm afraid.
posted by swimming naked when the tide goes out at 6:09 PM on March 20, 2011
posted by swimming naked when the tide goes out at 6:09 PM on March 20, 2011
I'm confused. Why an electric bike pusher, as opposed to an electric bike? This seems unnecessarily ungainly, heavy, and like reinventing the wheel. What is the purpose here?
posted by PareidoliaticBoy at 6:46 PM on March 20, 2011
posted by PareidoliaticBoy at 6:46 PM on March 20, 2011
Are their any hills or slopes in your area, if so;
1. You should put a regenerative braking switch on your handlebars (so that the motor charges up the batteries as you're going downhill while at the same time providing braking that is safer than using your regular brakes while the weight of the pusher bears down on you from behind). This could be done crudely with a relay and reversed diodes on the motor which the relay connects to the charge or directly to the battery.
2. You should use lighter batteries than lead acid. NiMH batteries give the same amount of watt-hours in less than half the weight. AA's might seem tiny, but in bulk they're cheap, and are commonly used in things like segways, bike motors, and even sometimes, electric cars.
Throttle/controller - I'd probably look into giant SCRs if you want to build a variable throttle. A cheaper cruder simpler system would probably be a huge on/off relay, controlled by a switch on your handlebars. Be careful your relay can take the ampage - other you might weld the relay into the ON position and have your own version of the Toyota uncontrolled acceleration issue! :-)
Single direction power - just use a regular bike rear wheel, (and possibly also consider not having the extra chain connecting the rear pusher wheel to the middle wheel), it has a ratchet built into the hub so you can coast. Switch off the motor and it will allow the bike to coast (ie allow you to pedal). If you connect the motor to the middle wheel which is also connected to your pedals, then it depends on whether you add a second ratchet to that hub.
posted by -harlequin- at 6:59 PM on March 20, 2011
1. You should put a regenerative braking switch on your handlebars (so that the motor charges up the batteries as you're going downhill while at the same time providing braking that is safer than using your regular brakes while the weight of the pusher bears down on you from behind). This could be done crudely with a relay and reversed diodes on the motor which the relay connects to the charge or directly to the battery.
2. You should use lighter batteries than lead acid. NiMH batteries give the same amount of watt-hours in less than half the weight. AA's might seem tiny, but in bulk they're cheap, and are commonly used in things like segways, bike motors, and even sometimes, electric cars.
Throttle/controller - I'd probably look into giant SCRs if you want to build a variable throttle. A cheaper cruder simpler system would probably be a huge on/off relay, controlled by a switch on your handlebars. Be careful your relay can take the ampage - other you might weld the relay into the ON position and have your own version of the Toyota uncontrolled acceleration issue! :-)
Single direction power - just use a regular bike rear wheel, (and possibly also consider not having the extra chain connecting the rear pusher wheel to the middle wheel), it has a ratchet built into the hub so you can coast. Switch off the motor and it will allow the bike to coast (ie allow you to pedal). If you connect the motor to the middle wheel which is also connected to your pedals, then it depends on whether you add a second ratchet to that hub.
posted by -harlequin- at 6:59 PM on March 20, 2011
Having the pusher unit absolutely rigidly attached may make regular riding hard. Even when you think you're going in a straight line, you're actually executing a series of very shallow S-bends.
posted by scruss at 7:20 PM on March 20, 2011
posted by scruss at 7:20 PM on March 20, 2011
Seconding scruss. Putting a rigid bar on the frame at the back with power at the end of it is going to make the bike hard to handle and it's going to put a lot of sideways stress on the rear triangle and the wheel. You'd be better off building a battery housing and powering the rear wheel that already exists.
posted by Dipsomaniac at 5:09 AM on March 21, 2011
posted by Dipsomaniac at 5:09 AM on March 21, 2011
« Older How do I manage a long stay in the hospital with a... | How do I get into a science writing career? Newer »
This thread is closed to new comments.
posted by hattifattener at 6:05 PM on March 20, 2011