MTSU Students Retrofit Hub Motors (Converting an Accord into a plug-in Hybrid)

[Frank Lee]

Yes, it seems wheel damage is often confined to the flanges where the beads are and the exterior (curb rash). And I certainly see the good in a larger diameter. Just make it so that the local teenage tire jockey isn't likely to damage it while manhandling the rims on the tire changing and balancing machines. Actually, make sure the rims will FIT on standard tire changing equipment.

Speaking of tires, what is the strategy for dealing with flats? Does the spare have a motor on it too? If you run snow tires on their own rims now do you have to stop doing that and change tires on the rims 2x/year, or are the rim components cheap enough to make multiples affordable?

[freebeard]

All these problems go away if you drive a car that can accommodate inboard disk brakes.

[cfg83]

rmay635703 -

Originally Posted by rmay635703

Signal Wires don't need to be much more than 32 guage or so and they don't even need to be true copper, these can be had for pennies and opticouplers can go to the moving bits if you are afraid of fatigue.

Having dealt with industrial equip & bluetooth & wifi, in a factory setting I can say anything wireless is NOT something I would want on an OTR vehicle. There are a lot of things in the environment that will make the blasted thing inop for seconds at a time or take it out completely until you get away from the problem.

If you were driving in the middle of nowhere, fine; in a city, no way.

I agree 100% that the physical connection is superior in the harsh environment of an automobile. I am thinking from a fast, cheap, and out of control POV that seeks to cut the *labor* of the retrofit. Isolating the mod to the wheel well means I don't have to figure out unique wiring routes for different cars. But after our conversation, the more I think about it, it may cheaper from a liability POV to make it physical wiring after all.

CarloSW2

[freebeard]

"First we kill all the lawyers" Shakespeare

A big part of the reason MIT does it is so they can use a smart phone as the controller. This enables crowd-sourced mapping, monitoring air quality, stalking your friends, etc.

Because of all the nay-sayers, I actually went and looked at the MIT site. Guess what. They use Bluetooth to talk to the phone. Guess what else. To quote them:

The whole generating and power-assisting system can be controlled through the pedals, requiring no switches or dials. Pedal backwards, and the regenerative braking is engaged, helping to recharge the system’s batteries; pedal fast, and you get the extra boost of power. “Everything is controlled by your feet,” Ratti explains.

Given all that, if I was going to take the other side, I'd say "What happens when 2 bikes are within 6' of each other?" But I have too much respect for the programmers abilities.

"Any sufficiently advanced technology is indistinguishable from magic" Clarke's Third Law

[cfg83]

freebeard -

Originally Posted by freebeard

...

Given all that, if I was going to take the other side, I'd say "What happens when 2 bikes are within 6' of each other?" But I have too much respect for the programmers abilities.

"Any sufficiently advanced technology is indistinguishable from magic" Clarke's Third Law

The first step in bluetooth requires the devices to negotiate their connection, aka pair-up, so I think(?) it's a non-issue.

CarloSW2

[Otto]

Originally Posted by Frank Lee

Yes, it seems wheel damage is often confined to the flanges where the beads are and the exterior (curb rash). And I certainly see the good in a larger diameter. Just make it so that the local teenage tire jockey isn't likely to damage it while manhandling the rims on the tire changing and balancing machines. Actually, make sure the rims will FIT on standard tire changing equipment.

Speaking of tires, what is the strategy for dealing with flats? Does the spare have a motor on it too? If you run snow tires on their own rims now do you have to stop doing that and change tires on the rims 2x/year, or are the rim components cheap enough to make multiples affordable?

Fair enough, and thanks again for your insights.

Local kid at the tire shop could be neutralized by use of a plastic sleeve during wheel installation, maybe a curved piece of coroplast so he does not bugger the facing parts during mount-up.

Modification to the wheel is simply the attachment of the permanent magnets. I don't know how expensive such permanent magnets are, but don't suppose they'd cost all that much, nor the electromagnets in the MTSU video, which look like thread spools. Surely the major portion of the ~$3K projected cost is for the controller, computer brain, and labor of installation. I've not read about the MIT wifi thingy yet, will do so with great curiousity, if such makes for a good, cheap controller device.

BTW, I've been wondering for months about converting a bicycle wheel accordingly, with the magnets held in place on the rim by the spoke mounts and/or JB Weld, and the electromagnets attached to the frame wheel support struts, so a magnet passes an electromagnet every few degrees of rotation of the wheel, getting a pulse with each passage. Somebody on the net says their bike conversion kit winds up with ~30 mile range and only a few cents per day of electricity, so I wonder how it might work if applied to a streamliner bike, i.e., Varna Diablo, and what sort of range that might get for the same juice.... Make both wheels motors, dispense with the crank/chain stuff, and ride to work for cheap.

[freebeard]

If I understand you correctly, it would require a ring of electromagnets attached to the frame as big as the wheel.

If you want to get into it with low cost, Google Fisher-Paykel washing machine motor. They come in other machines, too; like Delco.

[Otto]

[QUOTE=freebeard;327395]If I understand you correctly, it would require a ring of electromagnets attached to the frame as big as the wheel.

If you want to get into it with low cost, Google Fisher-Paykel washing machine motor. They come in other machines, too; like Delco.[/QUOTE


I'm just saying do what MTSU did with their magnets, but put them on the inner surface of the wheel instead of on the drum. Bigger radius = proportionately more torque per squirt of electric juice through the electromagnets, which also must be located further from the axis of rotation to mate with the permanent magnets on the wheel.

Suppose the magnets exert X lbs. of torque if 8" from the centerline. Move the magnets out to 12" from centerline by putting them on the wheel itself, and now you increased torque by 50%, with no weight gain. Since torque is what turns the wheel and since motors have max torque at 0 rpm, this is a huge gain for just moving the magnets outward, all else being equal. On braking, you also get more bang per buck with no weight for gain.

Actually, you might do all this while reducing overall weight, since now the braking is largely done by the regen mode of the motor, which is a generator when driven. So, regen mode takes braking load, so brakes do not need to be as big or heavy = less unsprung wheel weight = better handling and energy economy. Win, win, win.

Does this make sense to others, or am I off base here?

Also, thanks for the Fisher-Paykel thing, which I will bone up on asap.

[cfg83]

Otto -

Originally Posted by Otto

...

I'm just saying do what MTSU did with their magnets, but put them on the inner surface of the wheel instead of on the drum. Bigger radius = proportionately more torque per squirt of electric juice through the electromagnets, which also must be located further from the axis of rotation to mate with the permanent magnets on the wheel.

...

The funny part is that when I looked at this picture I mistakenly thought that the "magnet wheel" in the middle *was* the wheel :



CarloSW2

[serialk11r]

Hmm I'm a bit late to this discussion.
I think it's better to use a lower torque motor that's geared down, for reducing unsprung mass.
Turnigy AquaStar T20 3T 730KV/1280KV Water Cooled Brushless Motor
Watercooled, 2.1 lbs, 5kW peak power. Attach to the spindle, put a pinion and annular ring gear sort of thing on the rim. Should be no more than 3lbs increase in unsprung mass per wheel, the equivalent of going up a rim size or two. Looks to be completely sealed.

Regeneration with that is more complicated than with brushed permanent magnet motor but I imagine it can be sorted out.