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Old 09-24-2008, 01:04 PM
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TX_Dj TX_Dj is offline
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Default Re-conversion of a Scooter [pics on pg 2, post 17]

Ok,

So I've mentioned a couple times elsewhere that I'm working on my entry for the NTEAA "Scooter Challenge" which will be held at the November club meeting.

If my avatar image doesn't give it away, I'm a racer at heart. I've never been much of a fan of "Ball Sports", and I'll be quick to point out that my Pops was very supportive of me when I was in my youth, training me to be a racer... I would love to be a professional racer, but it just wasn't in the cards...

Now... that said, racers tend to get really secretive about what they do to their vehicles, and typically the only people who know exactly what's going on with them are the mechanics on the crew and the inspection officials... and anyone else is outright banned from seeing what makes one or another vehicle tick.

"Scooter Challenge" isn't a race, per se, though it appears it will be conducted similarly... after all, it involves vehicles, rules, competitive spirit, and the winners receive trophies... But what it REALLY is, is a cheap and easy way for club members who may or may not have previous EV experience to buy or build a scooter for entry, with the hopes that they will learn more about how EV's work, why they work, and have a lot of fun.

Because of the underlying educational reasons for the challenge, I see no reason to hide what I'm doing, because it may help other NTEAA entrants and non-members see what's going on, and either lend me some advice, or take some advice from me. I really *want* to "win" the silly little trophy (that's the racer in me), but I am more interested in helping people understand how EV's work, etc...

So... This will be my official thread for my "Re-conversion" of my scooter.

Background story:
Approximately three years ago, I bought a BladeZ XTR-SE 450 scooter (refurb) for something between $300-400 including tax and options. This was a little cheaper than factory new, and the scooter shop assured me the only reason it was a "refurb" was because it was one of the models that was used as a demo for a press release about that model. Basically they just cleaned it up, checked it out, made sure the batteries weren't toast, and slapped a discount price tag on it.

The XTR-SE 450 is a 24v scooter with a 450w motor, and a 20A peak output controller, with 12Ah capacity. It weighs about 50 lbs, and folds down for easy storage.

I used this scooter extensively for my commute to my old job downtown, where I would ride it approximately 2 miles from my home to the nearest DART Rail station, then I'd take the electric train downtown to the rail station nearest to my office, and ride the scooter the remaining 3 miles to the office. It was a LOT of fun, and I had my opportunity to spread the EV vibe to a lot of people. Though at the time gas prices were not as bad as they are now (we're talking pre-Katrina), most of the other rail commuters were park-and-riders, and they were most intrigued by the fact that I didn't have to find a parking spot in the jam-packed park-and-ride lots.

The old scoot did pretty well, but there were a few steep climbs that it was a little underpowered for, and due to this (and no proper instrumentation, and a poorly matched dumb charger) I was killing batteries with alarming regularity. Two trips daily, with a charge during my 8-10 hours at the office, and I was averaging about 80-100 cycles from a pair of batteries. Because of this, it cost me almost as much (if not more) to run the scooter and train as it would have to drive a 20 MPG car... but I didn't have to deal with traffic, and I had almost an hour every morning and evening that I could sit and relax and read a book. It was well worth the cost of admission in my opinion, but I had really wished I had better instrumentation (so I could watch what was happening) and wished I had a higher top speed, better hill climbing ability, and batteries with better discharge characteristics. Alas, I also understood that such would require an investment of a few hundred dollars to get everything "tweaked" the way I wanted. Then I changed jobs... and didn't need the scooter anymore, because there was no electric rail service anywhere remotely near the new office.

And along comes the announcement of the scooter challenge... and a clarification of the rules got me inspired. You see, one of the rules says you can spend a maximum of $500 on your entry, "including cost of the scooter". I was disappointed, because if I counted my battery replacements, I was already over that amount. Then the clarification came through... if the scooter was owned prior to the announcement of the challenge, the scooter was considered a $0.00 item, and you had your full budget to do as you please for the entry.

So... Having my excuse to finally do the things I've wanted to do to the scooter, I got busy designing my "re-conversion". I call it a re-conversion, because just like an ICE->EV conversion, every bit of the drivetrain and fuel storage will be gutted from my scooter, and it will be "re-converted" with all new components, just as if I were gutting the ICE and converting a car.

To recap the old specs:
Voltage: 24v nominal
Ah Capacity: 12Ah (2 bricks)
Watt-hours (max): 288
Battery current rating: 2C (10 seconds), 1C (continuous)
Battery Make/Model: Generic chinese SLA (Low discharge)
Controller: 24v, 20A peak
Motor: 24v, 450w peak
Motor RPM: 3050 rpm
Charger: Dumb charger, 2A, does not match the MFR's charge profile, nor does it shut itself off- ever.
Throttle: Hall Effect, Brake-lever style
Power Interruption: 20A circuit breaker, and a power switch which connected to the controller, and a brake-lever throttle kill switch.
Instrumentation: 3-color LED, roughly analogous to an SOC meter.
Gear Ratio: 70:12 (5.833:1)
Calculated top speed: 14.78 MPH

New specs:
Voltage: 36v nominal
Ah Capacity: 12Ah (6 bricks, 6Ah buddy-pairs in series)
Watt-hours (max): 432
Battery current rating: 10C (10 Seconds), 3C (7 Minutes)
Battery Make/Model: Power-sonic PSH-1255F2-FR VRLA 12v 6Ah (High Discharge)
Controller: 36v, 30A peak
Motor: 36v, 1000w peak
Motor RPM: 2600 rpm
Charger: 3-stage 36v, 1.8A, matches the MFR's recommended charge profile to a tee.
Throttle: 0-5V, twist-grip style, with 3-LED SOC meter
Power Interruption: 35A ATC blade fuse in-line with the battery pack positive, a power switch (on its own fused circuit) to a 70-904 36v Solenoid (contactor)
Instrumentation: 0-50vdc voltmeter, 0-30A ammeter, Cheesy SOC 3-LED on the throttle
Gear Ratios: 70:15 (4.666:1) and/or 50:15 (3.333:1)
Calculated top speed: 15.75 MPH / 22.06 MPH, respectively

Here's a couple pics of what I started with. I'll have pics of what it's turning into soon enough.


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Old 09-24-2008, 09:09 PM
3dplane 3dplane is offline
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Default Re: Re-conversion of a Scooter

Hey Dj!
I probably missed it somewhere but what is the actual race? Like ten laps around something? or who scoots in first after 30 minutes?
Cool little scooter.
Barna
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Old 09-25-2008, 10:05 AM
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Default Re: Re-conversion of a Scooter

Barna,

The challenge will be two parts. I'm still fuzzy on the exact details, but it's more or less like this:

1) Speed/Acceleration Test: Zip down to a cone, come around it, and zip back to the starting point. Lowest time wins.

2) Range Test: Round and round a pre-defined course. Whoever has the most laps within an hour wins.

The first one is no sweat. The second one may end up being won by whoever is willing to abuse their batteries the most. I don't want to go below 80% on mine, and I expect others will not either, but someone may.
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Old 09-27-2008, 10:00 PM
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Default Re: Re-conversion of a Scooter

Things are coming along nicely.

Found that REI has cheap webbing straps with quick-release buckles for ~$2. Using these to restrain the batteries within the scooter. Should work quite nicely. 1" web straps are very strong, and the large buckles should hold back lots of force if the batts try to come free in a wreck.

Finished tearing out the old rear crossmember, and welded in a replacement roughly in the same position of the old seat post receiver tube, but back a bit- serves two purposes, the cross member, plus it is a hard stop for the battery pack to keep them from sliding back into the contactor and other items I'll be putting behind the batteries.

Removed all the stickers from the frame and did a quick-n-dirty rattle-can flat black paint job on the frame.

Got the new throttle mounted a few nights ago, and got the cable routed thru the steering down-tube. Controller is mounted in its new home where the old one was.

Got the chain and sprocket and rear wheel completely degreased, and mounted back up- reverse of the old orientation (sprocket on the left now instead of the right) because the new motor turns the opposite direction had has a freewheel sprocket installed on the motor shaft. The chain had years of dirt and grease and grit on it, and thanks to the awesome degreaser that I use on the S10 before painting the frame, it is completely free of grease or oily residue. Will use a dry teflon lubricant from here on out.

Working tomorrow on the new motor mount. The new motor is a larger diameter than the original, and furthermore has its bolt holes on tabs outside the diameter... the original mount won't work at all. No worries, though... I'll get it worked out tomorrow.

Hooked up all the electrics on the bench last night and heard the motor run for the first time.

My battery configuration will change from the original plan, but only in the wiring... still using the same batteries and same number of batteries.

I've decided on this project not to get wrapped up trying to take pics as I go along... it's a short enough project that it'll be fine to just have before/after pics. It's going to be a whole different beast when I'm done.

Unfortunately, I didn't get out soon enough to pick up connectors for my wiring, and the only store I know of that has the connectors I need closed earlier than I expected, and is closed tomorrow. So... pics soon enough, but not tomorrow.
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Old 09-29-2008, 12:46 AM
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Default Re: Re-conversion of a Scooter

That looks great. I'm excited to see how you will modify it...
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Old 09-29-2008, 09:14 AM
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Default Re: Re-conversion of a Scooter

Anyone interested in seeing the scooter challenge rules, they are posted on our NTEAA website. That address is www.NTEAA.org.

After seeing DJ's scooter, I need to get mine going. It has just been sitting there and it needs a few things fixed before it is ready.
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Old 09-29-2008, 06:35 PM
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Default Re: Re-conversion of a Scooter

Hehehe Zemmo! Starting to feel the heat of competition now, are ya?

Should have some pics soon.

Spent yesterday afternoon and early evening building the new motor mount. The new motor is heavier, torque-ier, and larger diameter than the old one. As such, the new mount puts the motor beyond the reach of the stock chain. I was supposed to drop by the custom scooter store in Plano to pick up some chain this morning, but as morning-commute-autopilot would have it, I was more than 3/4 of the way to the office before I remembered.

Talked more with my EE friend, he's interested in the challenge my battery charging puzzle presents, and he's working feverishly on getting me a schematic to build the new charge system. Previously I was going to simply charge parallel banks of "buddy pairs", but after a lot of discussion and debate, he and I have decided it's a bad idea to put lead acid batteries in parallel with each other without isolation... so that's somewhat changed the charging paradigm. The design is not yet complete, so I don't want to let any cats out of bags ... but suffice to say I'm most likely going to end up with a completely custom charger rig as well.

Tonight I finish up a few things on the motor mount, and get it affixed to the scooter and get the motor mounted to it. My ammeter/shunt should be on my doorstep as well, if not today then tomorrow. Still not entirely necessary for the scooter to have a voltmeter/ammeter onboard, but if I can find a way to build a "dashboard" to mount them to, I'm gonna do it!

I'm saving pics for when the design is completed and ready to run, then I'm going to take a lot of photos and get a friend to videotape me running it. I'll still be running with "stock comparable" gearing at first, but that's just because I want to see how much more torque and acceleration it has with the same-ish top speed (new motor has a 15T gear, old motor had a 12T gear, but with the difference in max RPM the ground speed works out to just about 1mph faster)...

I'll have a "top speed" wheel sprocket on hand in time for the challenge.

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Old 10-22-2008, 11:13 AM
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Default Re: Re-conversion of a Scooter

Things are really coming together. Still no pictures yet... but soon!

I finally have all the parts I need except my "gofast-sprocket", or at least have them on order. The main problem here is that the BladeZ folks decided to use a non-standard hub size for the wheel, both in sprocket locating bore and in bearing surface to bearing surface width. It's making it a real bear to get a smaller sprocket installed!

Last night I got started on wiring everything up.

Pics real soon now.
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Old 10-22-2008, 12:40 PM
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Default Re: Re-conversion of a Scooter

We are getting down to only a few more weeks before the race. I still don't have mine up and running again. I have been watching craigs list for a parts scooter but haven't had any luck. Mabye I should convert the scooter into a contactor controller deal. So starting off at 12 volts and then switch it to 24 volts.

I am glad to hear yours is coming along a lot better than mine. We want to see pics!
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Old 10-22-2008, 06:00 PM
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Default Re: Re-conversion of a Scooter

I'll have pics up soon enough. I just want to be certain as to which nooks and crannies I'm stuffing the rest of the components, and/or finish the complete build, before I put any pics up... but there WILL BE PICS!!!
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