Motobecane 40T Moped conversion

[northernmike]

Update: brakes are functional, brake light switch is on order. New headlight from France has arrived, Castle Link and a GIANT Digikey catalog. No caps, as ordered, but a giant catalog, anyway. Promising.

Have a chrome luggage rack coming thanks to eBay... Looking for a horn. Might be useful, in this crazy city.

Freewheel adapter ordered from Matt to facilitate EMF-less coasting, Castle HV 110 should be delivered already.

Man, I wish I had a shop here at the downtown apartment. Having to wait for opportune weekends to work on this is just killing me.

$$ for a123s is being saved up, but it looks like it's going to be SLAs for the interim. Oh well!

[northernmike]

Update in non-hub-motor-drives forum. Goodnight!

[northernmike]

Status:

[fizzit]

Wait... Why are you putting a metal can around the motor? Won't that just heat up from eddy currents and simultaneously cause the motor to overheat? Sorry if I'm missing something!

[northernmike]

its a etek. no metal can.

[fizzit]

Sorry, I was referring to this:

[northernmike]

Yeah, gave up on RC controllers. Not enough off-the-line ability for me. I don't think aluminum cans are a worry, though, in terms of eddy currents. Steel might pose a problem, but I doubt alu would. The eTek has much better take-off power, and compatible controllers (Alltrax 4834 etc) are easily sourced.

All I have to contend with now is affording, mounting, wiring, and charging a battery pack that can feed this bike.

[Jeremy Harris]

I don't think aluminum cans are a worry, though, in terms of eddy currents. Steel might pose a problem, but I doubt alu would.

That motor will cook that alloy can quickly and it will suck a load of power, too. The eddy currents in aluminium will be much higher than those in steel, which is why I'm using an alloy disc for the eddy current brake in my dyno. You need to space that tube a lot further out from the motor rotor, with a gap of at least 1/2" all around it, preferably a bit more (the magnetic field will still be around 80 to 100G at 1/2").

The problem with putting lumps of alloy close to the motor case of an outrunner has already been documented here, and that was just a bit of alloy plate with a hole in it where the motor fitted - a tube will be far worse. I fitted my first boat motor inside an alloy box, with the motor too close to one face (around 1/8" or so) and the case got very hot very quickly.

Jeremy

[northernmike]

Ah! What is that unit, "G", Jeremy?

Interesting stuff.

No heating problems were experienced with that setup, but I didn't run it hard. I didn't have a chance to - I smoked my Castle hV110 a few days in.

The eTek runs nice and cool, too, as I'd expect it to. The bike only weighed 90lbs from the factory with the gas engine.

Now then, has anyone got any strategies for stuffing LiPo into the hole I made in the side of the gas tank?

[John in CR]

The bike only weighed 90lbs from the factory with the gas engine.

I've gotta get one of these. Stronger, lower, and longer than a bike, plus it's cheaper with cheaper but better tires and brakes with plenty of room for batteries. What's not to like? Get one with registration already done and that headache is out of the way too. Availability of these kinds of vintage mopeds is going to evaporate quickly after a few more e-conversions get done.

Do any of the mopeds have a reliable multi-speed tranny in the hub, or is it just those few with a planetary gear reduction? Actually a planetary gear reduction inside the hub has the makings for a simple Retro-Direct 2 speed with the chain running in reverse driving the sun gear of the planetary reduction for low gear. Then a chain reduction running forward for 2nd. You give up being able to roll backward, but that's easy enough to get used to and overcome as long as the bike isn't too heavy.

John

[northernmike]

Yes John - Any "V" model Motobecane includes the "MobyMatic" variator - or CVT. The engine is on hinged mounts with a spring behind it, and the drive pulley is a combination clutch / movable sheave pulley.

I considered keeping this feature for my build but took the easy road instead.

There are NUMEROUS performance versions, especially in France, as the kids there tend to tune these to oblivion. 50mph is pretty common.

Look to Doppler especially for these parts. Treats HQ (treatland.tv) is a good source in the USA.

[Gordo]

Ah! What is that unit, "G", Jeremy?

http://en.wikipedia.org/wiki/Gauss_%28unit%29

[spinningmagnets]

Eddy currents have come up before in discussion, I hadn't paid much attention before, but I've recieved several questions about adding a motor cover as an option. I purposefully made the outrunner-motors base-plate too large to allow that as an option (can always make it smaller later as needed). Making the motor-cover large, to create more airspace, is of course the option described here, but what are some appropriate "non-eddy" materials as our options?

PVC? Stainless Steel, fiberglass, "X"?...

[Gordo]

Eddy currents have come up before in discussion, I hadn't paid much attention before, but I've recieved several questions about adding a motor cover as an option. I purposefully made the motors base-plate too large to allow that as an option (can always make it smaller later as needed). Making the motor-cover large to create more airspace is of course the option dedscribed here, but what are some appropriate "non-eddy" materieal as our options?

PVC? Stainless Steel, fiberglass, "X"?...

Non-ferromagnetic SS will still conduct eddy currents, but even more so than aluminum. Not all SS is non-ferromagnetic. Your question begs the understanding of metallic compounds vs non-metallic?

[northernmike]

Guys I abandoned that setup a while ago and am using this, eTek now:



I should have appended to another of my posts on this project, I suppose, but here we are.

The previous photo of the bike in my living room is current.

I'm considering re-engineering the motor mount to incorporate the controller down there... maybe the next mount will be steel.

Thanks for the interest!