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.
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
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.