electric scooter :)
 

So i was buying some stuff off of a guy in my racing club and I noticed in his "crap for sale" list there was an electric scooter. I was already buying 300 bucks worth of stuff off him, so i told him to throw in the scooter (50 bucks) for free.

I should have it on Tuesday evening to play with. I really have no idea what it looks like or what model, but one thing's for sure... i'm going to mod it to go faster and farther :D

He tells me it "claims" a top speed of 15km/h. I'll check out what kind of battery/throttle/motor it has, and explore my options of bumping up the range, power and efficiency. If the motor can handle it, more volts. If the throttle is not advance, DIY controller... either way, it will be getting bigger/better batteries!

Nice! Let us know and take pics. :)

If it's this kind (with or without a seat)
http://www.extremescooters.biz/image...ricscooter.gif
I would very much recommend a helmet with a face guard.
I cracked a rib flipping one over onto a driveway several years ago, but the helmet prevented me from potentially breaking my jaw.

Whatever it is I might be able to help with specifics on modifying it.

That is VERY close to to the one I've got. It is called a "firefly" and any googling that i did tells me that they were pretty much only available at the CNE in Toronto (Canadian National Exhibit, big fair). It looks like a crude modification. There is a seat post and the hole cut in the deck to accomidate has not been deburred. Anyway, I didn't charge it and i just ran it around my messy basement for a bit. It had a hard time getting started, but would certainly assist a good push - probably just due to uncharged batts.

On to the fun stuff - it is driven by a MY68 100W 24V 2300RPM motor that is about 4 inches long and 3 inches wide. I would assume it has a 24V pack, but i havn't cracked it open to find out what type of batteries or control. It has an on/off switch and a crank handle throttle.

Step 1 - charge it and test it.
Step 2 - take it appart... i'll let you know when i get this far (very busy doing renos on the house)
Step 3 - examine the control system. If i am looking at a simple battery to pot to motor, then i'm ripping it up and making a PWM drive for it to get longer range and more power. A super-simple mosfet, diode, pwm system is cake - i already have a board with a coldfire mpu on it and some i/o headers.

System goal - take the scooter with a backpack to get groceries.

Crude modification or not, a seat's a good thing to have. Without the need to stand on the base, you can modify the heck out of the original Battery holders-maybe double or triple the capacity with multiple strings in parallel, and that's without upgrading the Controller. Plus you could add a basket or panniers since you no longer have to stand...

The thought had crossed my mind of replacing the batteries with a beefier pair, but i am concerned about weight. We'll see what the power is like when it is charged up.

When i get a bit of time, i'll be able to see where the weak-point is. ie - do the batteries have the current capacity to accelerate the motor well? Is the motor just a pathetic lump? is the controller so cheaply built that it can't supply a decent starting current?

I also considered taking the whole thing apart and using the parts in a bicycle conversion.... one thing at a time... it is on the charger now :)

Well... i'm thoroughly under-whelmed...

Fully charged, this scooter can not start on its own with my fully weight sitting on short carpet.

Give it a little push and it exhaggerates the push, then slows down.

I'll have to try it out on pavement before i make any real decision. At low speeds the thing is way too unstable to use the seat.

Funny thing... today at work someone came to me and said "we have these power mosfets that are overstock, you want them? They're garbage otherwise"... score, i just got 50 free IRFB18N50K mosfets... i'll be ordering some project board shortly for an LED project and i could try to hook up a mosfet bank to drive with the coldfire board that i have... unfortunately, this till take me a couple months considering the new house i'm renovating.

As I mentioned, this thing uses a MY68 100W 24V 2300RPM motor. Could any of you dc motor experts out there tell me if I can over-volt this motor?

Also, Ben told me that his motorcycle had the same acceleration, but lower top speed, when he dropped the voltage and greater acceleration when he upped the amps. Would i get better starting push from this if i paralleled the batteries? I assume i'd get way better system performance if i added a second pack in parallel. Oi... i need to do some current testing.

Of course the motor can be over-volted, but don't bet on the controller being able to handle it.
When over-volting the motor it will still be at roughly the same wattage rating, but will spin at a incrementally faster speed.
If you go above 150% of the rated voltage you will need to monitor the temperature of the motor.

So what's the point of the voltage rating on the motor? is that the voltage as which it will run continuously for infinite time? I'm expecting that I'll be building my own controller for it. When i crack it open, i'll look into the cost of adding an additional battery to bump it up to 36 volts or something... then maybe 3 more batteries to parallel with it so i can run to the hardware store with a backpack :)

That's the voltage at which the motor is expected to
- Not overheat
- Not destroy the bearings (which are rated for a certain maximum speed)
- Draw the indicated amperage under normal operation

A constant higher applied wattage than what is indicated will overheat the motor. A rotational speed too far above indicated and you'll start shearing the axle and bearings.
There are all kinds of ways you can tweak a brush motor beyond its normal factory specs. You can rewind it, add extra thermal management, or shift the alignment of the stator.

I had a 300w scooter of this type for quite a while. The motor handled 36volts easily, but the controller wasn't happy with the increase and eventually crapped out. The mosfets and capacitors inside of it probably weren't rated high enough to survive the higher voltage.

I have a blue one of those that I bought at a yard sale last summer for $2. It needed a belt and the throttle switch needed fixed. Mine is 24v 100w and doesn't have variable speed. The "drive" is just an on-off relay with some extra circuitry to make sure the speed is above 3mph before the motor comes on. I added a 3rd battery and it was a great improvement in performance but it melted the relay contact. I put a different relay in and bypassed the circuitry so it'll start the motor from a dead stop if I want. I've kept it at 24v since It wasn't my extra battery we tried. It only works decent on smooth level concrete. Even the road surface roughness slows it down alote. It may be worth trying 36v if you can mount the extra battery good if it has a hard tire and no suspension like mine. You will also want to see if yours uses the relay system to drive, and upgrade to bigger and better possibly variable speed control. These guys have lots of cheap parts to do that. http://tncscooters.com/view.php?page=Parts

mine is similar to that except it has solid rubber wheels, a removable seat post and a hinged handlebar so it can be folded down.

I never thought of scrapping the controller altogether in favour of a switch... the thing is so puny anyway that full-throttle-only would be fine.

I could also do a 0-12-36v stepping relay controller... hmmmm....

Hehe, I have one of these scooters too. I have no seat option with mine.
Picket it up second hand, has a busted throttle, and no charger.
Its a 24v system... (2x12v batts)

With no charger, I haven't had a chance to play with it yet.
Looking for a (cheap) charger... locally they want 100 bucks for one. :mad:

TNC Scooters (Scooter Sales and Service)
They should have something for $15 or so.

Ah, good price... I'll have to look into shipping costs to Canada.

Thanks,
Chris