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Re-conversion of a Scooter [pics on pg 2, post 17]

25K views 44 replies 7 participants last post by  TX_Dj 
#1 ·
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. :cool:

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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#3 ·
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.
 
#4 ·
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. :D
 
#7 ·
Re: Re-conversion of a Scooter

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

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. :D

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.

:D :D :D
 
#8 ·
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. :)
 
#9 ·
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!
 
#10 ·
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!!! :D
 
#11 ·
Re: Re-conversion of a Scooter

So, I got everything in its place today.

Checked and double-checked everything.

Plugged in the main pack.

Threw the switch.

The contactor said *CLACK!* and the controller diagnostic panel (some LEDs) lit up.

Back tire was off the ground, goosed the throttle and *WHIZZZ!*

Hooked my ammeter up to each of the two battery packs, and watched for the volts to change, and they were both changing, and I had voltage present at the output of the isolation diode regardless of if either pack was connected, and more importantly, with both packs connected. :)

Pushed it out into the driveway, put my foot on the deck, locked the front brake and yanked on the throttle... she spun up and started to smoke a little... the tire, that is!

Gearing is "almost stock", and works out to just about 1 mph faster than stock, due to the slower RPM but larger drive sprocket on the motor.

My "go-fast" sprocket is on order, and should be here mid next week.

A little problem though... while it is noticeably more peppy than before, it really doesn't seem to be all that different except on the minor hills around the house here. It will hold 15 mph where the old one would have dropped to 9-10 mph. However, I would expect far less voltage sag than the controller diagnostic LEDs lead me to believe, due to the parallel packs. Either I have an issue somehwere in the system, or I read the battery mfr's spec sheet wrong, or my isolation diode is causing me problems, or my ammeter shunt isn't letting all the watts get thru or SOMETHING. I dunno what yet, but I have all day tomorrow to tinker, and there's no light remaining today.

Oh, tomorrow I'll get pics once I have everything re-(re-)painted and secured permanently.
 
#12 ·
Re: Re-conversion of a Scooter

Couldn't resist tinkering with it more tonight.

Found that one of the battery strings was improperly connected. These batteries use .250" quick connect blades, and I'm using fully insulated connectors. One of them had the battery terminal wedged between the plastic and the connector, not quite a good connection for passing current.

Fixed that, took it out for another spin, and had no sign of sag from the onboard LEDs.

Decided to go for a "real" shake-down run.

Put about 7 miles on the scooter, full throttle, never let up unless I was going downhill or needed to slow for a corner or stop. Didn't sag once until I turned around to come home, which was mostly up-hill. Again running mostly full throttle at top speed, with a few spots where I slowed a bit going up hills to see what speed yielded the "green" light on the so-called volt meter that came with the controller, and then I'd slam it to the max again.

It never dropped below "yellow", and would pop back to "green" if I slacked out the throttle.

Got home and opened it up, not letting it rest at all, got voltage readings of 36.9 and 36.8 on the two strings of batteries. By the time I got the charger, the readings were already climbing back up due to resting.

Not too shabby for fresh batteries that still need to get broken in.

The freewheel sprocket is interesting, I must say. If I'm zipping along and release the throttle, it takes about 2 seconds for the motor to spin down... sounds kinda like something George Jetson would drive. :) I'll have to see about getting a video or something when I'm doing my pics.
 
#13 ·
Re: Re-conversion of a Scooter

And the band plays on...

Today I picked up the last of the parts to build my "dashboard" which will have the voltmeter, ammeter, and power switch that triggers the main contactor.

After last night's escapade, and the second pack "resting" all night, I had 37.9 V there, or 12.63 V per battery, which is still technically "100% state of charge" depending on who you consult. Not too shabby at all. Can't wait to get the voltmeter installed so I can see for sure what the voltage is at all times, and not trust a "dummy light" :)
 
#14 ·
Re: Re-conversion of a Scooter

Alas, another busy day working on the scooter, and I've run out of daylight.

The "dashboard" is finished, and just received its last coat of paint.

Looks like it may be next weekend before I get pics up. Drats.
 
#15 ·
Re: Re-conversion of a Scooter

Well... it's been a long road... and it hasn't been cheap...

But this ole scooter is just about done. The electricals and dashboard are all rigged in their final configuration, all instrumentation is in place and functional, all the painting has been done...

The only thing I'm lacking yet is the "go-fast" sprocket, which should be on my doorstep tomorrow, just in time for me to hand it off to my machinist friend, if he has time to work on it for me.

It's too dark right now, and the shop is too messy. I'll try to get up early tomorrow so I can snap some pics of the scooter in the morning light. "Early" for me means sometime before 9am (my shift starts late, and I'm a night owl anyhow). Probably won't be able to post the pics until I get to work... we'll see.

I love it when a plan comes together.
 
#17 ·
Re: Re-conversion of a Scooter

Interesting thing is... after I got the instruments wired up, it became immediately obvious to me that the "yellow light" wasn't due to voltage sag as much as a warning that I was pulling more that "continuous rated" amperage for more than a few seconds.

So, I only posted two pics of what it looked like before... but I'm going to post more pics of what it looks like after. go back to the first page if you need to see what it used to look like. It looks quite a bit different now. Take a look at the "diameter" of the motor from the "original pics" and understand that the motor was actually about half the diameter of the shroud around it... then compare to the size of the new motor. :)









I had "just enough" blue quick connect female connectors, and one of them messed up when I was crimping it... that's why the top side of the ammeter wire is just wrapped on the fuse box terminal.

If you look carefully at the last pic of the fuse box, on the right side you'll see 3 thick wires coming off the 30A terminals, those are the wires to my dual-diode package. two are fused from the batteries, the one in the middle comes back up and gets fused again before feeding the contactor solenoid.

Why the solenoid? Doesn't the controller have it's own power control?

Yes, sort of. The precharge circuit will draw current all the time even if the switch input for the controller is in "disable" position. In fact, it can only disable by running current thru that switch!

Now if I clack the contactor, there's a brief precharge pause before the controller engages its internal relay. Also, the contactor terminals are rated for far more amperage than the scooter is rated- thus if there's an emergency shutdown need, I can throw the switch on the dashboard without fear of welding the contactor terminals during disconnect.

I rolled around the neighborhood last night, checking volts and amps every time I passed a street light. I can pull 30A very briefly, but it seems to limit to about 25A not too long after that. Flat ground at "top speed" with this sprocket seems to pull about 12-14A.

The freewheel sprocket is a godsend, though... I can cut out power long before when I would have needed with the old setup and still coast pretty darn far.
 
#19 ·
Thanks Jared! :) Like I've been saying... better have some trophies with my name on 'em, cuz I plan on taking at least one home with me. :D

I do think I had my fuse box upside down when I marked the holes for it, and I think that's why it looks lop-sided in the photos. the holes are offset on the mounting flanges. I'll have to take the motor and tire off when I'm test-fitting and building a chain for the "go-fast" sprocket, I'll see if I can turn the fusebox upside down and make it fit "straight" like it's supposed to, otherwise I'll just have to deal with it. LOL

Edit: I see that the pic of the fuses I chose for posting here doesn't really show the crookedness of the fuse box... below is what I'm talking about:

 
#20 ·
BLAST!!!!!!!!!!!!!!!!!!

I just was staring at this picture and figured out why it's wrong!

The holes will be in the same orientation even if I flip it over. the problem is that I marked and drilled from the wheel well, which is a mirror image of the hole placement for the inside compartment. Argh. No wonder it came out lop-sided!

If I'm to fix that, it will involve drilling a 3rd hole... and if I get sufficiently motivated, I'll end up doing just that.
 
#21 ·
Welp... all the hard work paid off... I managed to pull 3 trophys at the Scooter Challenge. Only took two, conceded one to a little girl who was there on her little Razor vespa look-alike, that one was for "Best Looking" which hers certainly was.

We had competitors in each voltage class, 12, 24, 36 and 48. I had the fastest acceleration and top speed out of all classes. I also pulled the most laps overall with 80 laps, just barely squeezing past the #2 and #3 finishers (both in my class) after having repeated trouble with the scoot.

Twice during the race, one of my battery connections came loose, leaving me running on only one pack. I thought I was at the end of the line the first time this happened, and pulled over to look at the scooter and found the trouble and got back in and made up for lost time.

Here's a crude wiring diagram I made in MS Paint. :D



And here's a pic of the scoot & tropies:



I love it when a plan comes together. :D
 
#22 ·
That was a great race! You were definetly flying! I am surprised we were able to ride the scooters for an hour! I figured we would be dead in the water after 30 or maybe crawing at 45, but we were still going through the whole hour!

I had a question about your diode that prevents flow back to each battery. The one that prevents the batteries from discharging each other into the other. How does the charger work if it won't allow the back flow of electricity? Do you charge up each bank indevidually? Just curious how that works out. I think next year I will take on more of a project and not do the frankenscooter. Give you a real run for your money. :)
 
#23 ·
That was a great race! You were definetly flying!
And that was the slow sprocket! :D

The fast sprocket is a major amp sucker. It tops out around 22-23 mph and will pull a solid 30A until almost at that speed. I was going too fast and too close to the cone when I made my speed run. I thought I was gonna hit the curb!

The "slow" sprocket accelerates really well and will hold speed going up most hills. I noticed I was staring at my ammeter a lot on the uphill stretch, and when I was going slow up it, I was trying to pull 10A or less just to keep from killing the battery sooner.

I am surprised we were able to ride the scooters for an hour! I figured we would be dead in the water after 30 or maybe crawing at 45, but we were still going through the whole hour!
No kidding! I'd bet I could get the thing to go a lot farther than I have if I try to keep the amps under 15 or so. Also, if the A-pack didn't get disconnected, I probably could have made a few more laps. The harder draw on the B-pack while the other was disconnected really changes the discharge profile.

I had a question about your diode that prevents flow back to each battery. The one that prevents the batteries from discharging each other into the other. How does the charger work if it won't allow the back flow of electricity? Do you charge up each bank indevidually? Just curious how that works out.
Currently the batteries get disconnected to charge, and each bank is charged separately. I only have one charger at the moment. It's the closest match to the battery manufacturer's recommended charge profiles that I could find for under $30. Marvin's been working up a dual charge controller design for me to build. One unit, one connection, both batteries charged independently.

I think next year I will take on more of a project and not do the frankenscooter. Give you a real run for your money. :)
I spent most of the early evening wondering if I could build something like the mini-dirt bike that Bill was riding, but maybe in the 72v exhibition class. :)
 
#25 ·
Yes sir... all lead acid. The batteries I chose use a F2 .250" quick disconnect blade. I used 10 AWG wiring for the batteries and such, and the wires are somewhat stiff. The deck makes slight contact with the terminal connections, and the deck slides side-to-side slightly when cornering. It just slowly started to push that one positive connection off the battery.

Some of the suggestions I received included using some sort of rubber isolation damper to "stand off" the deck from the scooter frame to add a little clearance for those wires.

Truth be told, the batteries were about 1/4" taller than I had expected, because I looked at the case dimensions and didn't pay attention to the terminal heights on the drawing.

I think I'm going to get some 1/4" fuel hose and slit a gap in it and push it over the edge of the frame. It may be enough, and fuel hose is cheap and relatively lightweight.
 
#26 ·
I am so happy that I found this thread. On Saturday I am picking up this same exact scooter from someone at a garage sale for $5. The batteries don't hold a charge but it is in good condition and comes with everything it should.

My plans were to supe it up so this thread is perfect. Unfortunately I'm not on the same budget as you because I wont be using the scooter too often. But it will still be a fun project.

First thing is first. I need to find some batteries to make this baby carry by 200lb ass!:cool:
 
#28 ·
I am so happy that I found this thread.
Glad I posted about it, then! I was hoping it could help someone out!

On Saturday I am picking up this same exact scooter from someone at a garage sale for $5. The batteries don't hold a charge but it is in good condition and comes with everything it should.
WOW what a deal! I wouldn't pass that up even for twice that price. Scrap value alone should be more than that. The scooter weighs in at about 25 lbs with the motor and batteries and such removed. It has a lot of steel in it.

My plans were to supe it up so this thread is perfect. Unfortunately I'm not on the same budget as you because I wont be using the scooter too often. But it will still be a fun project.
Well, even though the challenge gave me a budget of no more than $500 to retrofit, I went well beyond what *I* would have liked to spend, while remaining JUST under the challenge budget. Between original purchase years ago (new, from a dealer) and the retrofit, I have something close to $800 invested in this scooter now. :eek:

First thing is first. I need to find some batteries to make this baby carry by 200lb ass!:cool:
Takes a pair of 12v 12Ah batteries, in a standard size. They're pretty easy to find replacement. If it still has the original batteries, take good measurements of each to be sure the replacements will fit before ordering. There's not a lot of spare room in the battery bay.

Also, be advised that the Mfr supplies the battery with screw lug/quick connect hybrid terminals, it looks like they tapped them for the screw threads. You'll likely need to replace the screw terminals in the stock wiring harness with quick connect fasteners, but that's easy enough.

The only way I could get more capacity in mine was to remove the seat post receiver and go with the 6x 6Ah batteries with the dual diode to isolate the parallel connection. During the challenge, I had wished I had the seat still, though I've rarely used the seat during my ownership of the scooter.

I don't run mine as much as I did when I commuted downtown on the train every day. In fact, I've only run it once since the challenge last month.
 
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