Apparently using roller skate wheels to connect a radiator fan motor to a bicycle tire is more difficult than I thought. ;-)
Today, a bit over two weeks from the first attempt, I finally got a workable solution, and though it involved a lot more components and work than I wanted, it was possible to use recycled bits of other things instead of making anything from scratch or buying anything new, which is part of the point of this whole exercise.
I don't have pics of the solution yet, but these are the two things I needed to connect together, also showing the holes described below:
Basically the skate wheels have two layers: a black nylon-ish core that has 4 small equally-spaced holes in it just outside the much larger main axle hole, and a blue rubber layer that's molded around that core, which extends thru the 4 holes to keep the layers from peeling away from the core at the center under sideways pressure (which will happen a lot during skating, but not at all on my contraption).
I took advantage of those holes and cut away the rubber from the center section, exposing those holes so I can more easily put screws thru them. I used those holes as a template to drill 4 identically-spaced holes in the aluminum motor-attachment hub that came out of the plastic fan originally on the motor--this was very difficult because the holes needed to be right on the transition edge from the flat plane of the hub to an angled section of the hub, forcing me to hand-drill (for each of the 4 holes) a partial pilot hole with a very small drillbit to make sure I didnt' slip and either screw up the hub or break my power-drillbit.
Since the plastic of the wheel is too soft to guarantee any hardware I use to secure the hub to the wheel will not just gouge or crush the plastic, I cut a circular mounting plate (for the opposite side of the wheel from the hub) out of some metal structural plate of an ex-copier/fax unit donated to me some time ago for parts. The steel was soft enough to use my grinder to cut and shape, and easily drill a matching set of 4 holes into (as well as a central larger hole for the assembly's mounting nut to be attached to the motor thru), but hard enough to not bend or crush easily from the force of tightening the nuts down during assembly.
I took 4 old molly-bolts (saved from somebody's junkpile in the alley years ago) apart and used some other nuts from that same ex-copier that happened to fit these bolts, along with lockwashers, and secured the hubs thru the wheel to the handmade plate above, so that the thing can't just come off the hub like it did during my first test run over two weeks ago.
It *should* work well, but won't know till I go test it. Already verified it turns the wheel fine as a "bench test", but that's with no loading. I'll do a little ride-testing tomorrow--I don't want to test tonite for a couple reasons--first is it's dark out already, second is that I am also still working on a battery-box to sling *under* the bike, instead of in those rear baskets. Assuming it survives the basic testing, I'll put pics up on the next blog entry, too. I won't be doing any thorough testing until daylight, though, as I don't relish the thought of finding pieces that come off in the darkness. :-)
Most of the other solutions involved making a whole new hub from scratch, which would require a lathe and a drillpress, neither of which I have, nor have I had the time to build either one (though I probably have all the parts). One other solution involved welding one of the motor-hub attachment nuts to a threaded rod, which would have been of the same diameter as the skate wheel axle-hole. The hub would be screwed down with this "motor axle extension", then the skate wheel clamped to the hub by a washer and nut on the outer end of that axle extension. I tried a few times, but could not weld a nut perfectly straight onto the rod, which caused so much wiggle at the farthest end of it that it would shake the whole bike like one of those motel vibration-massage-beds. So I had to give up on that idea, simple though it seemed at first. I'm sure if I could come up with the right jig to hold it all, I could weld it on straight, but it measured straight before welding the ways I already tried, and not straight afterwards, so I suspect something in the heating process is uneven and moving the parts around as I do it, or as it cools. I simply don't have enough experience at it yet.
If I had a drillpress and a tap-and-die set, I could also take the threaded rod and drill a hole in it to match the motor's threaded mounting axle, then tap threads into the hole so it could be directly screwed onto the axle without any welding--that would probably work fine, as long as I drill the hole into it perfectly centered and straight.
Part of the problem with batteries in the rear baskets is that the roughly three 12-packs of weight is at and behind the rear axle, meaning the front wheel is actively being pulled a bit away from the ground, even with my own weight on the bike. It doesn't actually lift off the surface, but it doesn't have anywhere near the traction it should, and doesn't steer responsively because of it.
Another problem is that all the weight of those batteries is focused on the rear wheel, which is what broke a spoke and damaged the hub on it (forcing me to rebuild it essentially from scratch earlier this week). That also has damaged my baskets, breaking some of the welds between their wire-sections, and even cracking one of the mounting points on it's lower mounting arms (which are some really tough steel!). I'll have another post about that later, as a warning to anyone else trying similar power-assist schemes of potential failures.
Moving 2 of the batteries to just below and in front of the pedals, and one of them to the frame triangle just above that will move the balance and weight load of the bike back to the center, where it would normally be, and also lower the center of gravity significantly (as the battery mass will now be about a foot lower down), making the bike much less prone to skidding or tipping than it was with them in the baskets. Also frees my baskets back up for cargo. :-)
Anyway, enough rambling, back to hacking some clothes-washer steel casing into battery enclosures.
Saturday, June 28, 2008
Apparently using roller skate wheels to connect a radiator fan motor to a bicycle tire is more difficult than I thought. ;-)
Wednesday, June 18, 2008
I now have a rearview mirror on the bike; I think it's an ex-Mazda door-mount mirror from some early 70's model. Also has anti-glare glass, tinted just a bit, which is something I've never had on any bike mirrors.
Advantage is it's more pivotable than the bicycle mirrors I've had before, and stays in place a lot better, without having to use any adjustment screws. Disadvantage is it wasn't meant for handlebar mounting, but 10 minutes with a hacksaw on an aluminum-handled ex-yard rake gave me a tube to put the mirror on and slip it over the handlebar end. A screw thru the tubes to hold them together, and the old rubber grip slid over the new tube (before mounting anything on it), and it works just like it did before, except now I don't have to turn my head to look behind me as much.
It looks wierd hanging down from the handlebars, but it's that way so I can still flip the bike upside down to service tires/etc when on the road, without having to deal with the mirror, and so it doesn't get in the way of my hands/arms if I turn sharply leftward for any reason. Also easier to see behind me without sticking the mirror way out to the side, since my arms aren't in the way of it.
Yeah, it means I have to direct my gaze farther from the front-and-center, but not nearly as much as if I had to turn my head to look backwards. :)
I used the aluminum tube rather than any of the steel tube I have for one simple reason: If something hits the mirror (like something projecting from a car that passes me too close--it's happened before), since it's tougher than a bike mirror, if it were mounted on steel it probably wouldn't break the mirror mount but instead would turn my handlebars and knock me off the road. Since it's aluminum, and thin at that, the inch or so of aluminum tube (where the mirror is bolted to) that's sticking out beyond the steel handlebar will instead just bend or break, and not be as likely to torque the bars out of my hands or knock me off the road. Still will be a noticeable impact, but I ought to be able to control it, at least.
One more free upgrade to the bike, this time only a few minutes to do, rather than a few hours.
Friday, June 13, 2008
What would you make with an old rackmount plate, a pair of roller skates, a couple of car radiator fan motors, some aluminum bracket, and a handful of nuts, bolts, blind rivets and a popriveter?
That's what I used to make the 2.0 version of this summer's friction drive. It's no beauty, but it works even better than 1.0 by a significant amount, though there are some major hurdles I have yet to overcome. One main advantage it has over 1.0 is it's location--it's out of the way of the baskets, leaving the top of it clear to be used as a cargo rack again. (I was missing that quite a bit, in the few days I used it with 1.0). Another is center-of-gravity: it's all a lot lower than it was before; bracket and motor mass is now not as likely to tip me over (still have the overpoweringly heavy batteries, but at least this stuff isn't up top now). It's also now clear of the rear wheel for service access--I could not have flipped the bike over to work on it with 1.0, but 2.0 is designed to not interfere with doing that.
The ex-rackmount-panel mounting plate is bolted to a pair of mounting brackets, which are themselves riveted to the bike frame itself on the rear triangle. It was much more secure than trying to clamp it, and easier and faster to do. The panel already had a series of holes in it that probably held switches and/or lamps for a mainframe computer system (that was likely all gone when I got the panel, so long ago I can't actually remember). It's nearly 1/4" thick, unlikely to bend under any stresses I might subject it to in this design.
It's mounted as close to the frame as I could get it, and still allow space for the motors to be between it and the rearwheel/tire of the bike, with clearance for tire movement/etc. That just barely leaves clearance for the pedal cranks (more later).
Closer pics of the panel and motors above. The friction wheels aren't installed in these pics. It might be a little hard to see, but the mounting panel is cut out around the motors and motor mounting points in two of three places to allow them each to pivot around the third mounting point, so tension against the wheel can be adjusted. If you've ever adjusted tension of fanbelts on alternators/etc in a car, you'll be familiar with the way this pivoting works.
Initially, I was going to have the entire mounting panel just slide back and forth a bit to pull the wheels against or away from the rearwheel tire, but I realized that would probably make tension on each motor different, since I'm not doing this in a very precise way right now, as a test version. So I used the pivot method of moving the *motors* instead. It slightly complicates the method of controlling that tension, in that now instead of just one spring to pull the motors away from the wheel, and one cable to pull them against the wheel, there now must be two of each. It is possible to combine the two cables into one, and I may do that, but still needs two springs, to pull the motors away from the wheel when not in use--that keeps me from wasting my pedalling energy on the motors, instead of only the rearwheel. If I use two cables, it also allows me to use one motor or two, as the need arises. That will likely increase my battery life, by only using up current on one motor unless I really really need the power of two (which will happen often enough to put two on here--they're really not very powerful motors--at 12v, I think locked-rotor current was around 5amps? And I'm absolutely sure they wouldn't sustain that current very long. I think they drew about 1.2amps while spinning their fans at max RPM in their original use, at 12v).
The top mounting bracket for the panel, along the outside of the top bar of the rear triangle:
The mounting bracket is pop riveted to the frame; you can see one of the rivets at the lower right. The other is hidden, under the big plate, between the two nut/washer/bolt stacks that secure the plate to the bracket. Those aluminum brackets were already shaped just about exactly like I needed them (or rather, I built it this way because the brackets existed!). The bolts are secured to the brackets with lockwashers on each side of the bracket, and a nut to clamp it to the bracket. That way I can easily secure/undo the nuts holding the plate to the bracket without having to have something to hold the bolthead from turning. The nut between the plate and bracket is also a spacer to keep the motor cases clear of the bike's rearwheel/tire.
These are the motors, with ex-rollerskate friction drive wheels installed:
The top one is on the left, and the botton one on the right. There's more clearance than it looks like for the top one--the pic is just at a bit of an angle from the front--the straight-on pic always blurs due to the autofocus light hitting something wrong when I do it that way. These are the pancake-style radiator-fan motors I got at the junkyard at the same time as the ones I used in the 1.0 version of this friction drive setup. They're a bit over an inch thick, instead of the maybe 4" thick the others are. The important part though, is that they are larger diameter, and apparently have more torque because of it, as they draw about the same power as the other ones do under the same load. I would have used these in 1.0, except there was no way to use them with any smaller hub than the fan hubs that came with them, which were such large diameter (~5"?) they would have been horrible drive wheels--much much worse than the 3" hubs for the other motors.
These are the roller skate wheels I mentioned getting via the thrift store in the previous post; they've become the actual friction drive roller wheels in this version, since they're much smaller than the fan-blade-hubs I was using before.
The bearings from inside them are a bonus--I didnt' expect it to be that easy to take them out, but they just pushed out with a little tapping. The way they're made, I should be able to use them for a few different things, including one of the ideas I'd had for a trailer-hitch bearing a few posts back. Don't need them for this friction-drive setup, though, so they get put in the "hmmm" box for now.
This is one of the wheels after hollowing out some of it's rubber to make room for the motor's aluminum fan hub core. I have to use those cores because they are already D-cutout for the motor axle, and I don't yet have a lathe or similar to make one myself. Might need to build a lathe, though, because there are more and more things I need one for.
Now, I didn't have any good way of putting the core really deep into the wheel, as there is a *very* hard plastic core to the wheel; perhaps nylon? I couldn't easily cut into it with hand tools, including my titanium-edged utility-knife blades, which I can whittle hard aluminum with! So I cut as deeply and symmetrically as I could, and then JBWelded the two together, ensuring the best balance I could get, which turned out pretty close to perfect (no wobble or vibration to the motor because of any off-centeredness of the mounting job). I let it cure for almost two days before trying it out, but in the end it didn't make much of a difference.
With the mounting plates/etc., the only problem I was seriously worried about was if I could make the pedal cranks clear all the fasteners, mounting plate, etc, and still have the motor casings far enough from the rearwheel treads to not have to worry about anything during rearwheel side-to-side flexings, such as during turns, etc (it doesn't move much, but it does move a little bit, especially with that heavy battery load in the rear baskets).
As you can see, it's a very tight clearance--maybe 1/8" max on the pedal end of the crank to that rear nut. It actually didn't clear at all until I cratered-out the area around the mounting hole there, with the angle-grinder. Since the rackmount plate I used for the mounting plate is nearly 1/4" thick, grinding down some of it here and there is not going to make a significant difference to it's strength in the directions it needs to be strong in. I also had to cut out a curved area near the shaft end of the crank, so it would clear the curving-inward portion of the crank at the mounting plate's leading edge.
I was in a hurry to test it out today, and had to go to work, thus shortening my time to work on it too much to do a normal fix for the controller that had burned out, so I looked for any switches I had that could handle the current I needed, and were big enough to easily toggle with gloved fingers.
Only thing I had easily accessible were some spare lightswitches in a wallplate in the utility-room junkbox, so I used one for each motor, both to limit the current flowing thru any one switch, and to give me some semblance of speed control (one motor on and one off means the first motor pushes against the unpowered resistance of the second motor, so it doesn't go as fast as it could, then both motors on means it goes perhaps three times as fast as only one motor, since neither motor is resisting the other). This was only a temporary first-run test; I won't be using it later on--but it did work, and fairly well--just hard to deal with being so big and on the center of the handlebars instead of easily reachable without taking a hand off of the grips.
There was a failure (expected, just hoped against) of the JBWeld holding the motor hubs to the skate wheels; even though they were embedded in the wheel a little, it obviously wasn't enough.
Both of them came off within seconds of each other, because I hit a pothole, which probably forced the tire to expand more against the wheels, forcing the wheels even harder laterally across the axis off of the hubs. The JBWeld couldn't stretch any more and broke. Only bad part is that one of the wheels stuck between my tire and seatpost, forcing me to a rapid stop, and wearing a chunk out of the skate wheel. I've got six more, so no problem there, but it was unexpected for it to jam against the tire like that, and the sudden braking was potentially dangerous.
So I need to make a much better way to fasten the skate wheels to the motor hubs (or directly to the motor axles) before I test it out any further. I have several ideas, but some of them require parts I don't have, and would be difficult to make without a lathe or other power tools I don't yet have. I can build a lathe from one of my drills, and that will probably let me make at least one of the ideas I have, but that's more time to do that, too. Well, better to spend extra time than to have it break yet again due to poor engineering and implementation. :-)
However, before the failure, I had done some tests on a clear-of-all-traffic paved path, one with inlets only at the ends, and no chance of anyone crossing my path while I was at speed (in case anything went wrong). Since these motors still have almost no torque at low speed, I pedalled up to about 10MPH, then cut the motors in and stopped pedalling. Unlike with 1.0, where I would have about sustained the speed and maybe gained one or two MPH before falling off and slowing down, I accelerated quite a bit, and pretty quickly, up to about 32MPH on motor power alone! I only let it go for maybe 10 or 15 seconds, because I felt too shy of letting it go any longer or faster (I don't think it would go any faster, but the bike felt skittish and I didn't wanna risk it). I also don't know how long it would last at that power level, with no input power from me, as the motors weren't designed to run at these power levels at all--I was just testing them with the 36v straight from the batteries thru the above switches, rather than thru any current-limiting controller. I doubt the batteries themselves would sustain that kind of power for long, either, as they are (as I've said before) old and not great to start with, which is why I am using 36v in the first place--making up in voltage what I am not getting in current.
It's also, AFAIK, not legal to run it at over 20MPH on public roads with the motors engaged, so there's another good reason not to work on it for speed. :-) Realistically, I don't want it to be fast, anyway, as I need distance, not speed. Just something to help me not wear *myself* out getting places during the summer, and to be able to go farther than I can on my own anytime/season.
I have a few ideas for switching in the third battery only when the first two drop below a certain level under load, and things like that, but haven't even drawn up a sketch of the circuit yet. Might just do it manually with switches/relays first.
Sunday, June 8, 2008
First, I had to change out the old computer reset switches I'd used for the motor-disengage-when-braking switches on the brake lever--they simply weren't meant to be handled the way they were when my gloves rubbed against them and pushed on them, and started to come apart. It's ok, since they were only a temporary measure until I find my reed switches to replace them with.
However, since I still hadn't found those (until today), I replaced them a couple days ago with the ones pictured above--those used to be internally-lighted aircraft pushbutton switches, from some cockpit control panel (I don't know what it was, there wasnt' much of it left when I got it in a junkbox from someone else, maybe 20 years ago or more). The lights aren't connected, just the momentary normally-open switches. There are still two of them because I want to be sure my gloved hand pushes at least one when I grab the brake in any sudden stop situation. It would suck to be unable to stop as fast as needed because of the motor still running during braking. :-)
When I get to reworking stuff for 2.0 of this friction-drive setup, I'll replace them with the magnetically-operated reed switches, which will require no thought or anything--they'll automatically just work when I pull the brake handle even a little bit (as the brake light does now). Note that the reason I don't just use the brakelight switch to do this is that the motor controller is on 24v/36v, and the lighting is on 12v--it would be more complicated for me to cross the two systems at this switch than to just add a second switch.
Now for the throttle update:
The slider throttle really wasn't very good, nor safe/easy to use, so I built a temporary twist throttle out of what was left of the plastic Scoot'N'Go throttle body (since it came apart shortly after I got the scooter's corpse). It had been a Hall throttle, but the plastic was broken in such a way as to be unable to really restore that function in any reasonably easy way, so I converted it into a rotating-potentiometer throttle.
I took the grip off the handlebar on the right side, added some strips of plastic (cut from the inner liner of a dead scanner I recently picked up from Freecycle to use as another headlight for a different EV idea) on the inside of the end of the handlebar, so the potentiometer (pot) would fit snugly into it and not rotate with the throttle, but not have to be glued or otherwise secured in, as I intend to change it to another design later, once I've had time to perfect the other idea.
The pot itself is from an old wonky VGA monitor that was donated to me a while back, I think from the horizontal hold. The plastic knob for the pot happens to be just a bit shy of being the same outside diameter as the throttle body's inside diameter, with one layer of plastic on the inside of the throttle body making up the difference, with just a bit of light sanding on the outside of the knob to make a snug fit. The shaft of the pot sticks out of the handlebar just a little, which meshes up with the knob's length so that the knob is almost entirely within the throttle body when it's all mounted on the handlebars.
The throttle body also doesn't fit the handlebar perfectly, as it was meant to be held on with a couple of set screws from the bottom on the mounting ring end, but that is the end that basically doesn't exist anymore (it's in several dozen pieces, where it cracked apart). So I shimmed that with plastic strips, too, with the wires to the pot running in part of the gap between the throttle body and the handlebar. I might drill a small hole in the handlebar just between the shifter grip and the throttle grip, and run the wires *inside* the handlebar, but that depends on how the other design (using a Hall) works out, since that version won't have any moving parts. Since it works as it is, well, I'll probably just leave it the way it is. If it breaks, I'll modify it.
The wires at the pot end are secured to it with silicone to provide a strain-relief (since the plain soldered-on-only wires broke just in trying to install the pot, due to the thinness of the wire used; just not enough strands to hold up with that kind of bending). The tabs that used to hold the pot to the board are now bent around the sides, with a bit sticking out to grab the plastic shimming inside the handlebar. One reason this is not secured better is so that if the throttle gets twisted past the pot's endpoints, either by me twisting too hard in use (not likely) or by
accidentally twisting it too far while trying to catch the bike if it falls or something (I tend to go for the handlebar grips when this happens if I'm standing next to it while working on it, parking it, etc).
The only real problem with the throttle is that it has too much travel between fully off and fully on, nearly 3/4 of a turn. I am working on a way to reduce that to maybe 1/4 of a turn, so I can "gun it" easily when I need it, since rapid acceleration from a slow speed to a faster one without destroying my knees/ankles is one reason for having the motor--for those relatively rare traffic situations where going *faster* for a second is better than trying to stop.
Mostly, it's so I don't get run over from behind by an impatient or inattentive vehicle driver that's going too fast to stop in time, if *I* stop. Or even another cyclist, because I run across them every day that don't ride by the rules of the road but still ride on the road, in traffic. Those types don't generally stop for stop signs or red lights (or watch for other vehicles of any kind, including other cyclists, or pedestrians), and they one day will probably either cause an accident or be hurt or killed in one. More than one of them has yelled at me (as they go around me instead of stopping as they should) for stopping at a stop sign or red light, whether there is traffic oncoming or not. Months ago, one of them actually ran into the back of my bike, because he wasn't paying attention and expected me (as a cyclist) to just run the stop sign. He cussed me out and went on--I didn't bother trying to even respond to him, since if he's going to run stop signs and not pay attention on the road, there's not a lot of point in it--he probably won't live long enough to run into too many more cyclists. I try to lead by example, rather than by lecture, anyway, but I know it doesn't really work very well (probably better than the lecture, though, based on my very few discussions with other cyclists that don't follow the rules of the road, who either think I'm stupid for doing it (and should ride on the sidewalk instead, which is much more dangerous than the road, in my view), or actually get angry at me for trying to suggest that they'd be safer if *they* follow the rules of the road, which were created for the purpose of making a predictable, reasonably safe place to travel, which it is whenever the rules are followed by everyone at the same time: pedestrians, cyclists, and drivers).
Enough ranting; that's not why this blog is here (but I had to vent a bit, sorry). Suffice it to say that the capability is, if not absolutely necessary, very handy to have every now and then.
The only real issue with it is that I need better batteries. The ones I have are simply too old and abused to hold enough power for this application--they can put out serious power for a very short time (minutes, at best), where they'll actually keep me going at a pretty good clip (I still have to hook up the PDA speedometer again), but quickly fade to a lower plateau that does still help out, but won't push very hard or fast. The plateau is sustained for a while, maybe 3/4 hour or less, then fades out to unusable very fast after that. At least, based on my 10-mile-each-way trip this past Saturday, where this setup did prove quite useful in keeping me from overexerting myself at midday in the high-90's weather we had. I would not have made the trip successfully at that time of day without many more rest/watering stops on my own; it put the trip at about an hour and 20-something minutes, where it would have easily been 2 hours or more if totally under my own power, in that heat.
I also decided to add some anti-theft (and anti-spill) bars across the batteries, pop-riveted to the baskets to make it harder to just grab the batteries out and run with them, should a thief decide to try. Now, it won't stop anyone determined to get them, but it will slow them down enough that probably someone will notice them messing with the bike and maybe say something to someone. Might even slow them down enough for me to get back to the bike from whatever store I am in at the time (since it's only locked up outside when I go to stores and whatnot, places I can't take it inside with me).
One way to help improve this version of the drive system is to make the power I do have be used more efficiently, which since this is still a friction-drive system, will mean making the motor-shaft-drive-wheels smaller, from the about 3" they are now down to about 1.75", using roller-skate wheels. I may trim the wheels down to 1.5" or less, if I can do them symmetrically and easily. I picked up a set of used but good-condition non-inline skates at a thrift store for a couple bucks (tried to find some on Freecycle and with friends first, but no luck). I had first thought to find a skateboard for the wheels, but the thrift stores all wanted at least ten bucks for any they had, and with only 4 wheels per skateboard, and 8 wheels per pair of skates, well, the price-per-usable-part makes it an obvious choice. :-) Once I have the new drive-wheel setup worked out (since it requires moving the motors from in-line with the wheel to beside the wheel), I'll have a new post about that change.
Wednesday, June 4, 2008
It's getting pretty hot again now, so I decided that even though I don't have an ideal solution, I do have a potentially workable one, with small motors and friction drive. I don't like friction drive for several reasons, but it's easy to do, and it does work, and I expect it to be pretty dry for my rides during the weeks (?) I will need it, which was one major problem trying to do it earlier in the year--too much on-and-off rain that made it not work reliably. One oily puddle and it just slips for several hundred feet or more, instead of providing any real motive power--and oily puddles abound when the rains hit, since they're infrequent and too little water to actually wash the streets clean of it--especially the edges and righthand lanes, where bikes generally must stay.
After having looked at a number of various ways of doing friction drives, especially with smaller motors, I found this idea:
It appears to have bigger ex-radiator-fan motors than mine by a bit, and he's definitely using bigger batteries, but the principle works, and is easy to build. I even have an improvement on it. His drivewheels are better than mine, too, being made from old skateboard wheels, while mine are just the ex-fan-rotors (for a couple of reasons). My smaller batteries means I don't need to use my trailer but I still could use that with the car batteries I've got around here if I needed the range (assuming the car batteries are up to the task--they might not be, as they're a few years old).
These two pics show my implementation of his idea. I didn't have any angle-bracket I could use (as he did), and decided I didn't actually need anything more than the flat plate, since I have the baskets already there for some support. I used an old rackmount faceplate, since it's aluminum and over 1/8" thick, quite stiff and sturdy, but easy to work with the tools I've got.
Cutting the motor holes was a bit of a challenge, as I had no hole-saw large enough, nor any jigsaw blades that would work with this aluminum. I used the doorknob hole-saw I did have to make the core hole, then used a 3" cutting disc tool to expand that to a hole big enough to pass the motor thru, with some play around it for positioning and fine-tuning the tension of each motor if necessary (turned out it was, due to the play the baskets have around the wheel/frame from their shape and mounting design).
I simply used machine screws to hold the controller and MOSFETs (already on their own little heatsink) to the ex-rackmount plate. The motors are held on with the same screws they had holding them into the plastic fan cages from the car.
A couple of angle shots of the rollers, which are simply the plastic fans with the blades cut off, then sanded to a rough finish for traction against the tire tread.
The darker yellow one is from the old Tercel motor I tried earlier this year, because after a very very bad pothole strike (over 6" deep!) due to a car that would simply not let me move farther into the lane even with my turn signal going, one of the newer ones came off it's aluminum mounting point:
Unfortunately there's no way for me to push the little metal hub back into the plastic--it has offset grooves in there that show me it was molded together as one piece, but can't be forced back together now that it's come apart. I consider myself lucky it didn't damage anything on the bike itself (especially considering I just rebuilt the wheels to try out various truing methods not two weeks ago, and they ride better than even when I first got the bike--a fair trade for about 5 or 6 hours of work on them).
This does tell me that these things aren't going to last, so I will need to find an alternative method of transferring the motor power to the wheel--I can still use friction, but I'm going to have to find something I can mount to those metal hubs (or directly to the motor shaft, which is very short and relatively thin). Probably skateboard or rollerskate wheels, as they're also smaller diameter which would improve the motor performance--they'd be able to spin faster while still getting the same wheel speed, so the motor wouldnt' be under as much of a strain being held back from it's "natural" speed at the 24v I'm running them at (assuming full controller output). I did some calculations a few days ago for what motor speed I should have for various size friction drive rollers vs the desired wheel speed / vehicle speed, but now I can't find the clipboard I had the notes in, or I'd put that info here. :-(
This is what the whole bike looks like with the motor system on it:
A bit uglier than it used to be, but it's sort of hard to tell that these days. :-)
That improvement to the idea I borrowed is simply a way to disengage the rollers from the wheel for various reasons, when not using the motors.
I added a notch in the plate for each bracket wire of the basket it had to cross, so it could seat down in between them, and have room for an adjustment for tension against the wheel. The front edge of the plate is notched to fit under the basketwires at the front, so it will act as a pivot, and the rear edge can be pulled down by this:
I took a rear-shifter off of the very first donated bike I got for this project (the green Huffy), along with it's cable, and mounted it as close to the inboard right side of the handlebars as I could get and still easily reach it with the righthand. The cable passes to the back of the bike, then (since I didn't have an actual mount to use for the end of the cable sheath) thru the slots on a hose clamp that's around the back end of the basket. That gives the cable something to pull against. When the shifter is up, as in the middle pic, it pulls the back end of the plate down which puts the motors' rollers in contact with the tire tread. When it's down, like in the last pic, it releases the plate which then doesn't pull the motors against the tread, and will (when I put a return spring under the plate) eventually actually pull them away from the tread altogether.
That lets me use the motors when I need to, but disengage them completely so they don't interfere with pedalling when the batteries die or something else goes wrong (as it inevitably will). I can also do it on the fly, while riding, at speed, so I don't have to stop to disengage (which might not be possible in traffic, sometimes) because of a problem. I can also use this feature for testing motor/controller/etc issues, without having to either prop the bike up to keep the wheel off the ground, or taking the assembly off the bike. Kind of like a "neutral" gear. :-)
There is also a throttle, which at the moment is just a slider potentiometer, because the Hall sensor broke during installation, and I didnt' have time to dig out my other salvaged ones to replace it, but I did already have the slider pot right there in a junk bin from something else I'd been fixing the day before. I do want to put the Hall throttle back in, so I can use it more like a typical handlebar-throttle again--that's a lot easier to use than this one. If I could, I'd like to get a throttle off a motorcycle, or something else, that's made of metal, instead of the plastic ones I've run across so far. Similar to what was done in the design I based this motorizing scheme off of, where he used a dirtbike throttle, and used it's cable to actuate the thumb-style throttle he has for his controller. I'd probably put a magnet on the throttle and a hall sensor on the body, though, as is often done with the cheap plastic throttles on ebikes and scooters, mostly because the controller I'm using was designed with that in mind (the resistive throttle I'm using now had to be put in a voltage divider network to get any actual throttling range out of it, and it still doesn't control over the full sweep of the slider--min and max are less than 1" apart despite the nearly 2" of travel).
I put the scooter's "ignition" switch and power meter in a much better place this time:
I still can't see the LEDs in daylight at all, but in deep enough shade or indoors they're easy enough to see. Knowing how much power I have left is not critical anyway, but nice to know. This time I put the switch/meter down at the frame's headstock tube--this means the cables from it don't have to flex, and it's one less thing cluttering the handlebars (they're pretty full, something I don't like). I don't need access to either of these things during a ride, only at the beginning and end of it, when mounting or dismounting the bike, really, so they're fine out of the way here. I can still reach and see them if I have to, during a ride.
I considered cutting the plastic shell that the scooter used to house them in and mounting that there, too, to keep the dangling wires better protected, but realistically it's just more stuff on the bike, and isn't tough enough to protect it from anything serious anyway--not even weather. I might still do it eventually, if it turns out that I keep this setup for any length of time. Depends on my mood and my "copious spare time". :-)
Well, lights, anyway. Right after the previous post I got busy with non-bike stuff again, so now I'm back with the tidbits of stuff since then. This includes pics of the red-LED replacement/additions in-progress (since there's just the video in the previous post, and the one before that covers only the amber ones). I also visited a Pull-A-Part junkyard during a half-price Memorial Day sale, and got a few parts off of various cars to use; unfortunately only one car even had any LED lighting, and it was so badly trashed from whatever wreck put it in the junkheap that I can't tell you what kind of car it used to be, except that it was Japanese (since it was in that section of the yard), and red. Since it had a nearly-intact 3rd brakelight in what was left of it's airfoil bar above the remains of it's hatchback, I pried that out and bought it, and used it intact as my brakelight (since I haven't had time to take the lights apart again and finish the actual brakelight the way I wanted to).
This is just a snapshot during the process of replacing the amber LEDs with red ones, for the side markers in the rear. They're so bright that the camera barely picks up the room's 4x 40w fluorescent tube lighting of the countertop the module is sitting on.
This is that third brakelight unit, ziptied above my ex-scanner-nee-lighting module.
The left pic is with the camera flash on, and even in that you can still see the lights--I didn't modify the car's module at all--it's just a completely transparent sealed plastic unit with 9 LEDs, which are just about as bright as the LumiLEDs I used for the taillight, though they are a different shape (and probably manufacturer). The 3rd brakelight module was made by Stanley--dunno if it's the same Stanley that makes tools and automatic doors and whatnot. Interesting maker name for a part off a Japanese car?
These are some pics of the front marker/signals, which are amber, and which do not alternate like the rear ones--these just change brightness by about 1/2 during signalling; it simplified things in front, since I only needed one color (as opposed to the red rear side markers plus amber rear turn signals).
It's supposed to blink on and off completely, but the way I designed it to flicker, I just have a 2n2222 transistor wired with it's collector at +V (as are the LED string anodes) it's emitter connected to the LED string cathodes and the current-limiting resistor for the strings, with the other end of that resistor at ground. The turn signal generator (module out of that scrapped electric scooter) provides the base a positive-level signal when it's activated, which is supposed to force the transistor to short across the LED string and pass all the current directly thru the resistor. Since it's short enough durations, it won't hurt the resistor or transistor, which do get warm but not hot. Unfortunately, the transistor apparently can't pass enough current to pull *all* the power out of the LED strings' signal path, so I either need a larger transistor, or a different circuit (I used this one because it's the simplest one I could use that would not be wasting power and a voltage drop on that transistor *except* when it's in use--I didn't want to run power thru it all the time).