Fechter's Original Zappy Scooter

[fechter]

My first E vehicle was an original Zappy scooter that was made in the last century (1999). The story is long, and is probably scattered around in a bunch of really old posts here.

I got the Zappy so that I could put it in the trunk of my car and ride it from where I park the rest of the way to work, which is typically beween 1/2 and 1 mile. Good in theory, but the stock Zappy couldn't handle the kind of hills I was dealing with in San Francisco. Not only was the motor too weak, but so were the brakes.

One time, early on, I came down a hill and the brakes totally faded about half way down the hill. This was a pretty steep hill, about 15%. By the time I got to the stop sign at the next intersection, I was going faster than I would want to jump off at. By luck, no cars were coming, and the next block was much less of an incline and I was able to use "Fred Flintstone" braking with my foot to bring the thing to a stop.

To be continued...

 

[Ykick]

Looking forward to hearing more about that little guy... Some ES member has my old electric Xootr which was leading edge for it's day but I guess hindsight has a way of being 20/20?

 

[fechter]

In a quest to make it up (and back down) the SF hills, I saw others that had added an additional 6v battery to up the voltage from 12v to 18v. I happened to have a good supply of 6v batteries, so I gave it a try. The 18v mod was a big improvement in speed and power. Unfortunately, after letting my son borrow the scooter for a ride around the neighborhood, it came back with a smoked motor.

I searched a while for a more powerful motor, but was unable to find anything in my price range (cheap!) that would fit in the existing frame. At some point, I decided to rewind the existing motor. In addition to the rewind, I also added a blower motor to give it forced-air cooling. This lasted for about a week until it smoked again on the way to work.

Now it was time to get serious. I could tell the stock motor was not really designed to give much more power and the ceramic magnets were prone to getting demagnetized by high currents. The plastic insulation that protected the windings from the iron laminations in the armature had melted, allowing the windings to short out. Searching the surplus junk web sites, I came across some arched rare-earth magnets that looked like they would fit in the existing motor housing. I had to do another rewind job too, but this time I used high temperature Nomex insulation between the armature and the windings.

Rewind in progress:

Rewind complete:

Since the new magnets were a bit thinner, I had to add a ring of sheet metal to the magnet ring to reduce the inside diameter a bit. The new magnets were also a shorter arc, so I cut up pieces of them and tiled them together to make the proper size.


Tiling the smaller pieces in. The magnets were glued in with epoxy. Since the pieces repel each other strongly, I had to used wooden wedges to hold them in place while the epoxy hardened.

 

[mwkeefer]

Leave it to Fechter to smoke it twice then redesign the guts of the motor!
-Mike

 

[SilverSurfer]

Nice work bro! Got a great thread rollin here. Like the details to quality! Awsome. SS

 

[swbluto]

One time, early on, I came down a hill and the brakes totally faded about half way down the hill.

I totally know about that fear. I ended up putting a switch in to short the motor wires so that I could coast to the bottom of steep hills (albeit at a pretty slow speed. But, hey, it's safer than having the brakes completely disappear.)

 

[def215]

i love the rewind job fechter! i have a commonality in you about rewinding my motor(not because it smoked or anything, just for fun...lol). do you know where i can find similar magnets like that? im still running the crappy stock magnets and i wanted something stronger like neodynium magnets or something similar.

ill stay tuned for this. fechter's scooter log might get interesting!

 

[liveforphysics]

Were you trying to save copper there? lol

 

[fechter]

With the enhanced magnets, the hill climbing performance was dramatically improved. I also added a blower motor and drilled the ends of the motor for forced-air cooling. I still had issues with going downhill however.

The stock band brake sucked and was prone to fading as it heated up. I tried adding some aluminum fins to the drum and filled the inside of the drum with a chunk of aluminum to increase the heat transfer. This helped quite a bit, but was still indadequate.

I tried making a plug braking resistor out of a piece of aluminum tubing with a bunch of 20ga wire wound around the outside. I used a small microswitch activated by the brake mechanism to disconnect the motor from the controller and connect it to the resistor for braking. This worked fairly well, but I eventually melted the wire on the braking resistor.

 

[fechter]

i love the rewind job fechter! i have a commonality in you about rewinding my motor(not because it smoked or anything, just for fun...lol). do you know where i can find similar magnets like that? im still running the crappy stock magnets and i wanted something stronger like neodynium magnets or something similar.

Unfortunately, those were suplus magnets and the supply dried up. I haven't found anything with the right curvature since. It would be possible to tile rectangular mangets into an arc, but it's hard to tile them since they repel their neighbors very strongly and want to flip over. It takes a pretty strong clamping setup to hold them in place.

 

[fechter]

The on/off type 'throttle' of the stock Zappy was pretty brutal with the new motor setup. It had a tendency to want to throw you off and do a wheelie every time you hit the trigger. So to avoid this, I went for a motor speed controller. At the time, there were very few available, so I settled on something called an MCIPC-24, which was designed as a wheelchair motor controller.


At the time, it was $36, so within my price range. It had reverse and regenerative braking and was rated for 24v. I modified the relays so that reverse was disabled. I built a new battery tray from sheet aluminum so I could install two Hawker 13Ah batteries and up the voltage to 24v.

This worked out pretty well other than the regen had no current limiting and had a tendency to make the belt skip during regen. It was also hard to control the regen since it was the type that kicks in as soon as you reduce the throttle. No coasting mode. I eventually built a regen current limiter circuit that would prevent the regen from going over the level where the belt would skip. This worked out great and made going down the hills much safer. The friction brake was hardly needed on moderate hills and fade was reduced on the steeper ones. The brakes still squeaked like hell though.

At this point it looked like this:

 

[fechter]

Topic back from the dead....
I need to reload some of the corrupted pictures.

New chapter:
After gathering dust in my garage for a few years, I replaced the blown controller with one from a Vego scooter and gave the Zappy to Mr.Electric, who used it for commuting for a while in downtown SF. At some point it became a class project for his students and was given to Lou Seal, the team mascot for the San Francisco Giants. The thing is still running!

We just put a new tube in your Zappy. The mascot said he took a big jump and crashed and they won big that night. Next game players requested that he repeat the performance. He took a big jump , didn't crash and popped the tire.

Vintage pic (circa 2003) of me riding the Zappy in a hill climb race