Currie Kick Scooter conversion

Personally when i do the boma im going to go about it like you have done, draw it out in function and scale then work out my fill area on each side of the tooth then i will half it and run dual strands paralleled, so two layers on each tooth with equal length twin strands to get max copper fill and low resistance.
Two winds of 17awg paralleled will perform the same as a 14awg of equal length and turns and can be packed in tighter, A parallel wind will pack better to give lower rpms and can be paralleled In divisions of your choice to give the same resistance of a larger gauge wire but with more copper fill if the correct gauge is selected.
So theres two rules here,
#1 theres an optmium guage wire to suit the design tooth its being instaled in.
#2 if copper fill can be improved in a motor theres room to improve performance in one way or another, depending how u divide the multistrand wind up resistance wise compared to stock there will be different effects.
* Lower IR = faster speeds, less torque, higher current use and capability.
* Simular IR = slightly slower speeds, more torque, a bit lower current use a bit higher current capability mainly due to better efficiency gains less heat waste in windings compared to a poor stock motor like the boma
* Higher IR = lower speeds, more torque low current use and capability
Ill be aiming for the best size conductor for copper fill and a similar overall IR.

Some better successes with winding. I have 22 awg wire. I was able to run 4 strands and get 13 turns. The KV is of course a little higher now, but I have also gotten a little more copper on each tooth. Since it's many small strands, I'm not over worried at how tight the winds are like I would with much larger gauge wire. Probably if I had been more careful, I could have gotten 15 turns on each tooth.

So 4×22awgs = 16awg resistance wise
13 turns worth don't nw the length but from that could work out the full resistance of motor and compare to stock did you measure stock resistance ?

Ianhill said:

So 4×22awgs = 16awg resistance wise
13 turns worth don't nw the length but from that could work out the full resistance of motor and compare to stock did you measure stock resistance ?

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Don't know how reliable it will be, but my DMM will go well below 1 ohm. I can measure the resistance of the removed windings and compare it with the new ones on the stator. This is a first attempt at motor winding. If it works, well cool. I'll order some 16, 18 awg and 22 awg 10LB spools after a while. Smaller strands are so much easier to wind than big strands! The burned out 2000 watt BOMA I have will get 14 awg. Now that I'm actually winding a motor, I'll want to experiment with different winds and turns. This little outrunner is easy to work on, remove the stator and cost me nothing so it's a good choice for learning on. Assuming this wind works, I'll run the motor on it until I burn it out or get tired of this particular set up and want to try something else.

BTW...removing a stator from an outrunner is very likely destructive to the windings. I drilled four holes around the perimeter of the output bearing and tapped them for 10-32 threads. I then used 4 screws to push the stator off. I still dinged a wire which is why this rewind happened. The motor was already a professionally done wind.

I also have an 80-100 I picked up for $45. It has damaged windings. I'll rewind it too and add halls. I has a couple of broken magnets I need to replace.

I don't think I'll get the stator out if the boma it looks like tongue and groove or jig saw pieces around the outer of the case and then they are laminates the full length of the can very strange design I think if I press it out it will fall apart so I'll have to rewind it in place.

Good work your getting stuck in best way to learn I learnt more out of college than in, even still with both ways it not much sence in there .

The bomas design is not to bad for Eddy's ,The laminates are pretty thin and thats then divided around the can so it could be a fairly efficient motor.

Ianhill said:

I don't think I'll get the stator out if the boma it looks like tongue and groove or jig saw pieces around the outer of the case and then they are laminates the full length of the can very strange design I think if I press it out it will fall apart so I'll have to rewind it in place.

Good work your getting stuck in best way to learn I learnt more out of college than in, even still with both ways it not much sence in there .

The bomas design is not to bad for Eddy's ,The laminates are pretty thin and thats then divided around the can so it could be a fairly efficient motor.

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I'm going to press out the stator on my 2000 watt boma. It will still be easier to rewind it not in the can than in. I doubt it will fall apart. It was assembled as individual teeth that interlock together and then pressed as a unit into the can. The interlocking teeth made it super easy to wind a single tooth individually and then slide that tooth onto the rest of the stator. For us, taking the stator apart will probably be a bad idea so rewinding it as a whole unit is probably the better way to go. Also, the interlocking stator teeth is probably a bad idea for several reasons. You want very thin stacks and I think these ones are .5mm which is rather thick and allows lots more eddy currents. The Currie motor has very thin stacks...probably .2 or .3mm which is much better. Regardless damaging the stator stack is very easy to do and trying to take it apart is asking for things to get damaged. you want the individual stacks to be insulated electrically from each other. My expectation is that fishing the wire through the gap in the teeth will help winding a fair bit...if the wire fits between that narrow gap. Otherwise it means threading the wire down in the space between teeth. That will be a royal pain. These motors have fairly long stator stacks so keeping the wire flat against the stator teeth will be a problem. The Currie motor has 1" tall teeth so cramming a plastic implement between the teeth to flatten out the wires is pretty easy. With something much longer...well "UGG!" comes to mind with thick wires.

Im going to press my spare boma out and have a good look at it there seems to be a plastic insert inside each tooth i think they seperate and inside the tongue and groove bits on the side theres a drift that locates the single bits together after close examination it may look worse than it actual is.

Ianhill said:

Im going to press my spare boma out and have a good look at it there seems to be a plastic insert inside each tooth i think they seperate and inside the tongue and groove bits on the side theres a drift that locates the single bits together after close examination it may look worse than it actual is.

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I have everything to make a press specifically for the BOMA motors. I just never built it. LOL! I started constructing it, but then "other" EV things got in the way and it never got built more than getting the parts together and creating a base for it. I think those plastic parts just cap the tops of each tooth, but don't go down the sides of the tooth.

I should finish winding the Currie outrunner tonight and get it put back together. I think on this third set of teeth, I'm going to try for uber neat winds to see if I can make more wire fit on each tooth. It would be cool to get another strand or two on each tooth. I have about 100 feet of 22 awg still so that will get me there. I'd even unwind the other 2 phases if needed and redo them neatly. I want to leave it at 13 turns per tooth which in wye will get me similar RPMs as I was getting in delta and have better torque and of course more current handling...all of which is better! Then who knows, switching to delta might be way too much for this little ride. 50mph on this tiny scooter might just be waaaay too fast. It's not like I lack batteries to do whatever I want with it and I have the thing already running at 48 volts compared to it's original 36 volts. I also have a kelly 7230 that is WAY too powerful for this tiny ride. If I ever draw 150 amps continuous on this thing, I'm pretty sure very bad things are soon to follow...like my death. Anyway the 7230 is good for 90 volts so pretty much the sky is the limit. Who knows, maybe I should just get an alien 120100 for it. Is 25Kw too much power for a 40 pound scooter?

Too late I suppose, but I should have shaped a large washer to fit on the stator that I then epoxied to the stator...rather than just using epoxy like I did. The washer would keep the windings out of the center of the motor so that if I were to push the stator off again, I wouldn't bung up the wires and would protect the stator stack from the damage the screws do to it.

I got the Currie outrunner back together tonight.

This is the rewound stator. There's 13 turns per tooth and slightly more copper per tooth than before. The motor was wound to 16 turns so it ought to be a little faster now.



This is the stator with all the phase wires terminated. I'm bringing out all the phase wire ends so I can connect the motor delta or wye externally. The winds are a little taller than before so the bell sits closer to the windings. I had to flatten them a little so there was no chance that the bell might hit the wires. I also added a washer under the bell so it can't sit as low on the stator. That took care of any clearance issues and the motor still went together like it was meant to go together that way.



It's kind of hard to see between the stator teeth, but the halls are in there. I zip tied the board to the windings. It was epoxied to them before. I nearly broke the board getting it off of the windings the first time. The zip ties ought to hold just fine and the actual halls are glued in place.



I should have taken a picture of the wires all secured to the underside of the stator. Anyway, I used several zip ties to secure all the wires together so nothing would vibrate and slowly fatigue. The stator is now pressed in place. I tried the motor out for a few seconds with things just loosely placed on the motor frame to make sure it all ran and it did. Then I pressed it all together and closed up the motor. The halls all work and the motor runs on 2 different RC controllers, but for whatever reason it wont run so far on the sensored controller I intend to use. I have it wired for delta right now. I tried a couple other motors on my controller and they run fine so the controller is OK, but I don't know what is going on with the motor...yet. This is different than having the phase wires and halls connected up wrong. I wont do anything at all. I'm wondering if the way I have the phase wires connected together is the issue, but then why do the RC controllers work?

Try and spin it while reving the controller might be struggling to start it.
I bet it feels rewarding completing your first wind.

Ianhill said:

Try and spin it while reving the controller might be struggling to start it.
I bet it feels rewarding completing your first wind.

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I'm stumped on this one. I spun the motor, but that didn't get it going either. I've tried all the different hall and phase combinations, but there's nothing on any combination. It's weird though. The motor runs on an RC controller and the halls work so I don't know.

and yeah...it's cool to have done a wind now, but it would have better if it actually worked.

If it runs on sensorless and assuming the contriller definallty works its a timing issue, I would check the halls pinout make sure its wired correctly, make sure each hall is in the center of each grouped stack and make sure the controller is setup for 120° can't say much else, teething problems thats all its testing your dedictation it is.

Ianhill said:

If it runs on sensorless and assuming the contriller definallty works its a timing issue, I would check the halls pinout make sure its wired correctly, make sure each hall is in the center of each grouped stack and make sure the controller is setup for 120° can't say much else, teething problems thats all its testing your dedictation it is.

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I marked where the halls were originally and then put them back in the same spots. I'm wondering if maybe the rewind puts the halls on the same phase? They all activate separately when I manually turn the rotor. I took the weekend off of messing with EV stuff so no news. I don't know, maybe its the way the phase wires are connected together? LOL! I'll mess with it more later. The phase wires are soldered together at the bullet connectors so relatively easy to reorient them. I wanted to test the motor and then do the wye/delta switching later.

I can't help with the motor it's not infront of me to test, I know the boma winding pattern how they make it so neat and more just a little hint as not manys ever commented on my thread or helped me with information.
Phase belt winding.

Ianhill said:

I can't help with the motor it's not infront of me to test, I know the boma winding pattern how they make it so neat and more just a little hint as not manys ever commented on my thread or helped me with information.
Phase belt winding.

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I'll have to mess with it more later. Who knows, maybe I screwed up a winding (too many or too few winds) and the RC brushless controllers can't detect it and the sensored controllers can.

Try moving the hall sensor plate one tooth to the left.

Ianhill said:

Try moving the hall sensor plate one tooth to the left.

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Thanks for posting that JPG. I knew there had to be a reason why some motors have the halls between the teeth and others have them in the centers of the teeth. This motor has gaps between the teeth for halls. They aren't between every set of teeth so I can't move one left or right.

Well further developments...

I found a used castle creations 160 amp RC motor controller on ebay. I tried it out on several motors including the rewound currie motor and it worked fine under no load, but promptly burned out under a small load on Friday. There's $160 down the drain and my one and only attempt at using RC motor controllers for an EV project ends there! I'm pissed! I know people do it all the time, but lets face it EV grade motor controllers are a better choice. Worst case if you burn out the mosfets, they are replaceable. On an RC controller, they are all surface mount and virtually impossible to replace. As a result, I have purchased a Grinfineon controller which will be here in a few days. It's a basic irf4110 based controller that can run sensored or uncensored, but that's all I need for this scooter. Hopefully it's not a total POS.

Over the weekend further progress was made on this scooter. I want to add a full compliment of lights and a horn to it. My blue scooter more or less evolved into what it is today. I want to actually plan this thing out from the get go, rather than making changes as I go. As a result, I have started with 2 cables made of high temp 22 awg wire. One is 10 conductor and the other is 8 conductor. I have mapped out all the signals I need to control from the handlebars into those two cables. The cables are cut and the ends are tinned and ready for connecting to things.

So that means Batt+, batt-, load -, +12 volts, +5 volts, head/tail lights, side lights, l/r directionals, throttle, tempurature sensor, brakes and a few other things. The only extra cable will be for the speedo sensor at the wheel. Everything else will go into the battery box. I need to buy another handlebar switch cluster. I thought I had what I needed, but when I went to find it yesterday, I couldn't find what I wanted. I probably never ordered it and just thought I did. LOL.

I am waiting for some stainless steel set screws for the shunt so I can wrap that up in electrical tape. I haven't used a contactor before, but they are just a big switch. This ride will have a manual contactor so I can disconnect the battery from the rest of the scooter. The contactor has a 1k 10 watt resistor across its switch terminals to eliminate inrush surges. The only things that will be powered up behind the contactor are the watt meter. On that note, the watt meters I use are two way so I can use it to measure discharge and charge wattage so I have wired it in correctly for that purpose. On my blue scooter, the watt meter is inline with the motor controller and nothing else so total load is an unknown and I can't measure charging amp/hours.

On the subject of watt meters, I recently purchased one of these. It's functionally identical to the other watt meters I have been using for more than a year now, but with a few exceptions. The other watt meters had no setting in them for max and min voltage or max amp hours. This new watt meter does. As a result, the meter "knows" what full and empty should look like with out having to actually charge to full or discharge to empty to "teach it". The one I purchased came with a 50 amp shunt, but I'm replacing it with a 150 amp version for the Currie. It's physically the same size as the older watt meter and comes in a small plastic case that's mostly water tight already.

http://www.ebay.com/itm/122176087798?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT


I have also completed the battery pack. It is made of 3 10,000mah LIPO packs for 12S. I added a couple of pieces of plywood to the sides of the packs so the cells can't swell and then zip tied them together. The whole thing got wrapped in Kapton and then I added a BMS and more kapton tape. THe BMS is wrapped in Kapton separately from the battery pack and then wrapped again as part of the battery pack. I have 4 of these BMS's and originally used them on my blue scooter back when it ran off of 48 volts. They've been collecting dust for a year now. This BMS is a perfect solution for a smaller ride like the Currie. The battery pack terminates in two 6mm bullets that then go into the shunt/contactor. The output side of the shunt/contactor also have 6mm bullets for the motor controller. There is a deans T connector in parallel with the controller wires that will feed power to the lights and horn. I have probably 60 M/F deans connectors and they are not getting used for anything else so I use them for auxiliary power connectors for stuff. 15 amps is plenty for stuff like a bunch of LED lights.





I have also made a 24 position version of the back distribution block. I considered using the front block in the picture since it's already made, but I need 24 positions, not 16. Wiring this thing up will begin soon. I have the old brake levers from my blue scooter. They include brake switches. I have some small DC-DC converters coming. They are good for 60 volts in and whatever I set them to out at 2 amps. I'll use one for 5 volts and 3 in parallel for 12 volts. These converters are really small...1.5" by 3/4" so they hardly take up any space at all.

On other notes...I am probably going to get an 80-100 outrunner for this scooter from Lunacycles after a little while. The Currie motor is fine for now, but with the Grinfineon controller, I can run so much more wattage and passing cars on a tiny ride like this is hilarious.

I've been groaning over the battery box in this thing since I got it, but never came to any consensus on what to do about it. It is open on both ends and wastes about 40% of the space it could be using. I want a battery box that keeps dirt and water out and uses all of the available space it can take up. I haven't built it yet, but the front will be curved and the back square to match the steel frame. I'll make the ends out of wood and then get some diamond plate aluminum sheet for the belly and long sides. Bending and cutting the aluminum will happen on a break and shear I have access to. The two ends will be made of stacks of plywood that are then cut to fit the shape of the frame ends.

Massive update loads of juicy stuff, the battery's are much better like that it won't curl their edges gonna be a nice ride once it's done.

Thanksgiving isn't my thing....it's just bad memories to me so I pretty much ignore it. Anyway, I did some more work on the kick scooter today. The steel battery bay was just a bit small and didn't use the space available very well and it was open everywhere and allowed dirt/water in. I had been looking at it for a good while now and been wanting to do something different/better, but hadn't decided what that was until a few days ago. I'm going to make the whole thing out of wood and then bend some diamond plate aluminum around the underside to protect the bottom and sides. I didn't find the diamond plate in a sheet large enough for my purposes or thick enough yet, but that's a minor detail.

This is the underside of the frame. The wood spacer fits the profile of the frame. I decided to not try to bend the back part in to match the frame. It's a little wider back there than the frame, but once the deck is attached, you wont be able to see it. The back part of the spacer isn't in place yet, but it's made and waiting for the glue to cure on the curved part. I cut a through mortis into the stack of plywood on either end and then cut a 1" long tenon into the ends of the side pieces. I wanted the sides and front to be super ridgid. I used gorilla glue for everything which is water proof and it swells into all the gaps to make a better bond. I'll put a couple of screws through the joints once it's all cured to be sure it stays all locked together. The back piece will get a couple of screws through it to secure it to the sides. I have a pocket screw jig that I'll use to attach the back piece. All the screws will be hidden inside.






All assembled...This is a closeup of the back part. Those screws are there thanks to a pocket hole jig. It's also glued in place, but the screws are doing most of the work. I'll add a couple of wedges into the corners so the spacer is supported on the frame in the back corners. That will come later.

More battery box updates...

Old vs new. The old battery box was 2.25" deep. The new box is 3" deep inside. Obviously the new box is a good bit longer and it doesn't slope at the front and back anymore. It's just flat inside. The old box ended 1" short of the back cross brace and a good bit of that was sloped too. The front of the old box partly went up under the down tube section, but now it's close to 2" longer and it used to slope up in the front too. The side walls were about .25" inside the frame tubes. Now they are flush with them. I've essentially gained about 50% more space inside the box. The new box bolts onto the underside of the frame with 10-32 screws. Once I have the diamond plate, I will also run some more screws into through the metal into the frame sides.




Various pics of the new battery box. I just painted it.

Nice bit of carpentry by there for an IT guy, woods a good insulator gives me an idea to let me ride the cold months with a wood winter jacket for my battery box.

Ianhill said:

Nice bit of carpentry by there for an IT guy, woods a good insulator gives me an idea to let me ride the cold months with a wood winter jacket for my battery box.

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Thanks!

I'm waiting on a few parts to arrive, but this scooter is pretty close to rideable. The new motor controller and some set screws will arrive probably Monday. Oh yeah and a switch block for the handlebars for lights and new handlebar grips. Then it's mostly just assembly. I want to make a new deck for it too, but that's pretty easy to make.

The Grinfineon trapezoidal arrived today. I changed out the power connector for and XT90 and the motor connector for some 6mm bullets. I also, moved the enable switch wires to outside the controller so I can turn on the controller with a key switch.

This is the controller. Pretty much everything you need to know is on that label. There's no settings or switches or anything. You basically plug it in and go.



The board...that's 12 IRF4110 mosfets.



These are the anderson connectors that came on the controller. Pretty useless if you don't use anderson connectors...which I don't. Also, these little andersons are good for 20 amps, not 40 amps so even less than useless. And the replacement 6mm phase bullets and an XT90 for power.




And the other connectors...phase, CA, throttle, brakes and the two enable wires I brought out.



I guess I should have waited to try it out before modifying it. I could have crammed wires into the andersons and used them to hook up to power and a motor, but I assumed it was good and went right to modifying it. Anyway, I'm running it sensorless at the moment which it can do and it has problems with all my motors. GRRR! I posted a video.

https://youtu.be/zpjYmUFIHrY

Of all things to work sensorless it's the old 1500 watt BOMA. I tried it sensored and the controller would not detect the halls. I tried the BOMA on my crappy Chinese controller which only works with halls and it was fine. I tried my 3220 with the halls enabled and it ran OK all the way to full throttle. Without the halls, it was jerky at low RPM's and got to about 30% throttle and started getting jerky again and then the controller shut off. I guess it kind of works, but not reliably and I intended to use it sensorless.

I have completed the battery box. I was going to cover the whole thing in aluminum, but changed my mind. I used a piece of 1/8" thick aluminum angle instead and wrapped the front and sides with it. It goes part way around the back of the box too. The box bolts onto the underside of the frame. I used nine 3" stainless 10-32 screws to mount the battery box to the frame. It's not going anywhere. The aluminum around the bottom edge should be able to take a pretty hard hit and protect the battery box inside. Except at the back of the box all the screws are on the bottom of the box so they are not visible. To make the curve around the front, I made releif cuts in the aluminum angle. I haven't done it yet, but I'll use a little locktite on the screws once I'm ready to make it permanent. I'll paint the aluminum and the outside of the box red so it matches the scooter. I added a foam strip around the top of the box so it would seal up to the underside of the frame. There's no gaps anywhere so I shouldn't get any water or dirt penetration at that joint.







This space up here will be interesting. I intend to take a single piece of plywood and trim it to fit around the three down tubes. It will get some foam tape under it too so it seals to the frame. I'll then attach the deck to the front piece via a piano hinge. I intend to make the deck wider than the frame by several inches. The back of the deck will screw down to the frame right in front of the back tire. I doubt I will use those screw holes in the top of the frame for anything. You can see the contactor in the picture. It's a close fit, but the contactor fits between the frame tube perfectly right here. The frame protects the contactor key from accidentally getting turned off