Polaris Trail Boss EV Conversion Project
I traded for some EV components and was looking for a project to put them in. An Advanced A00 4009 motor, Alltrax AXE 4844M controller, main contactor, reversing contactor, Curtis meter, lugs, wire, fuse, etc. I didn't want to do a motorcycle so eventually I settled on an ATV to use mainly as a utility vehicle and perhaps to groom half a mile or so of cross country ski trails in our back yard. I put an ad in craigslist and wound up with a '87 Polaris Trail Boss with a blown 250cc 2-smoke motor. A few hours later I had the ICE gutted and the remains power washed. The original transmission was a CVT driving a simple forward / neutral / reverse gear box which has a chain drive to the rear, solid, axle. It would be nice if it had a limited slip rear end but I already got more than I paid for. Rear brakes is a disc mounted to the F/N/R transmission. It's not on the axle, though that would not be a difficult conversion. It has front drum brakes that seem to work quite well and will probably work better once I go over them.
I'm thinking that I will remove the original F/N/R transmission and replace it with a jack-shaft, a disk brake on the axle and a contactor forward / reverse via swapping the field windings on the motor. The transmission is pretty big so removing it will give me more room for the motor. Or would I be better off using the mechanical F/N/R box instead of the contactor one, if possible?
My second question is batteries. I will be running 48 volts total and I'm thinking something in the 30 AH range. What are good brands for use in EV's that are subjected to bumps and jarring? Has LiFePO4 technology really proved itself when it comes to expected life with a proper BMS? Where do I find a well designed BMS, preferably in kit form? My gut reaction is to go with SLA and four independent chargers. Charging via solar panels is also a possibility down the road.
I tipped it on its side and...
...all this junk fell out ;o)
If you go with SLA I'd suggest Greensaver Silicone batteries. They started out with a "bad rep" but personally I like them. Check out the SP27-12 or one size larger. I think four separate chargers is the easiest setup.
Consider LiFePO4 with a BMS - less weight and cheaper in the long run (due to increased cycle life). Check out the Goodrum/Fechter BMS available at tppacks.com. As far as "are they reliable" there are folks that have had good results when using a BMS and there are others that have had terrible results when not using a BMS. It is newer tech and so there's less anecdotal evidence out there.
If you want to do the calculations yourself then check out "Build Your Own Electric Vehicle" (can't remember the author) - that has a good chapter that takes you through all the calculations. Although I don't think it accounts for increased power needed for off-road and snow. There are online calculators - can't remember the URL's right now though.
Good luck and keep us posted. It's amazing what falls out when you tip it over, isn't it? ;-)
It sounds a really interesting project. Have you seen the EVATV produced in Scotland. It might be worthwhile for you to look at that layout. Also both China and South Korea are producing EVATV's.
Jacobsen used to have a very good small electric vehicle similar to an ATV. This ran on the same batteries and controllers as the big golf course ride-on-mowers.
Best of luck
I just started a similar project. My 2000 Trail Boss looks very much like yours but I picked up a 36 volt all but mechanically dead golf car. The Trail Boss tranny was the straw that broke this guys back. I've got the engine and tranny loose but not out - tomorrow's task.
It’s kind of looking like the left side of the tranny is part of the rear left swing arm bushing / bracket. Anyone have experience with these chassises? Drawings?
The plan at this time is to mount the motor on the swing arm atop the rear axle. At 66 my jumping days are pretty much over so I’m not too concerned about the static load on the axle.
Three 12 volt golf car batteries in the engine-trans compartment and I should pretty close. If life and machines were only this simple.
I could use some help on the drawings and advice on the swing arm.
The engine would have fallen out if I had rolled the chassis over but not that stinking transmission. It flops around but really seems hung up on the left swing arm bushing. This left bushing is quite different and seems to have part of the transmission centered inside it. Tomorrow I’ll pull the bushing off and see what happens.
The motor I have, which is paid for, is wider than the transmission so it won’t fit in there as to center it on the swing arm rotation hence the above the axle configuration. It’s a three speed motor so besides the original Trail Boss transmission being toast I’m going to try this motor direct drive.
I went to the Inter-State battery shop today. They have these great 12 volt deep cycle golf car batteries that measure in at 7.25 X 11.25 X 13.5 – W X H X L – but they’re just too big. I have the 36 volt golf car charger so I’m pretty hooked up for a set of batteries that are compatible with it. Does anyone know of a slightly smaller deep cycle that would work in this application? I live on a five acre farm so there won’t be any really long runs but the farm does rise some 250 feet over a 700 foot run.
The Polaris project rolls on along. I gave up on being nice about getting the tranny out so I fired up the reciprocating saw. 5 minutes later and the broken tranny was in my storage box labeled EATV. My skeleton and spare parts look identical to the above pictures.
I’ve decided on the Trojan 30XHS batteries. Input welcomed of course. The color isn’t right but they seem to have a great reputation. I’m having mounting plates cut out of 1/8” steel next week and the battery group 31 strapped trays are on the way in the mail. This is going to be a tight fit which will challenge regular maintenance.
I’m thinking that instead of building a platform for the motor that I’ll just have a plate cut out of 1/4 inch steel and bolt it to the axle hub assembly. My local welding shop has one of those computer controlled plasma machines. WOW!
There are always surprises in the used equipment department. Mine is not in this rough of shape but a few grommets and the like will be needed.
What kind of batteries are you using to have the luxury of leaving the tranny in? I've been watching you-tube stuff and most of the electric units there mount the motor somewhere on the rear swing arm axle assembly. This is true for the retros as well as the new stuff that has been coming out the last couple of years.
I think you're doing some very nice work.
I was nervous about hanging the 60 pound motor off the rear center hub as well but as I look at the many other "electric ATV" on Youtube I see most of them are doing the same thing. Not using the tranny (mine was dust anyway) gives enough space for one of the three 12 volt deep cycle batteries as well. Actually I'm thinking just marine batteries to start and experiment with before popping the $200 each the nice stuff sells for.
I've been toying with cutting the bottom out of the fuel tank as well seeing how the seat uses its back edge for the front seat support. You've pushed me over the edge.
Thanks for the motivation.
The pivot point would be nice but there is less travel room as you get closer to the main cage. A short chain also has a certain draw to me as well. I just flipped the sprocket guard and everything looks pretty good for clearance.
My motor plate reads 3 HP and 300 RPM at 36 volts. Another site on the web maintained that 4 HP and 400 RPM would be the result of 48 volts. I'm very battery space tight so it's going to 36 volts. I wonder why the great difference in HP ratings for the two motors (yours and mine)? I hate to sound like an ignoramus but they look to be about the same size. I'm also using the Cushman resistance style speed control. It came with the dead golf car and an electronic one was looking close to $300 if not more. I want to feel this pony run me up and down the driveway a few time before I spend very many dollars on it.
Congratulations on the movie and the ride. I haven't come very far as I'm always drawn to "chores" and away from "tools".
I tried to look up your Odyssey 22Ah AGM batteries but couldn't find them. I'm still centered on the Marine deep cycle that Costco sells for about $80 a piece. Your physically smaller batteries are very fetching but I think AGMs of any sort cost about twice as much and I have the three battery shelves almost in and they're close to level. I'd be interested in alternatives. The nice thing about lead-acid units is that I'm thinking I can use the original Cushman charger which is built for 36 volts and has a simple timer on it. I hope my 3 - twelve volt batteries will be compatible with the original 6 - six volt battery charge load.
I wish I could do the quality of work I see on your unit but we go with what we've got or we get left behind. That's the rationalization for just hooking the Polaris throttle cable up to the original Cushman speed control / reversing box. I'm hoping I'll have some of the control I saw as you backed into your parking spot.
I doing some wiring and would like to move a wire in the left hand switch handle device. How the heck do you get those cable ends out without screwing the connector completely?
Thanks for getting back to the thread so quickly.
The jewelers screwdriver and pointy thing has been my approach. I built cables for a few weeks and we used a slitted tube that came with the connectors. It just slid over each wire from behind and collapsed the locks for removal. They just pushed in and automatically locked during assembly. I'm approaching the utility knife attack point of mind. There is a locking wedge that goes in from the back and when I first looked at it I thought it was a slam dunk. Why do so many of those Slam Dunks byte you right where some of your darkest thoughts occur.
I'll put my 325 glasses on and see if I can prevail without pulling a knife on this desperado.