kart buggy thing

I recently overheated my ME1003 spinning out continuously in snow that was deeper than the vehicle could handle. I decided that it would be a good time to do a partial tear down/rebuild as well as a 72V system upgrade. A couple people have expressed interest in the kart which has prompted me to start this rebuild thread.

The kart body has been heavily altered. It is an American Sportworks Carbide 150cc 2 seater. I came across it on ebay as a barn yard find that had been only slightly resurrected by a tractor mechanic. I cleaned it up and drove it for only 2 minutes before arriving at the conclusion that the 150cc motor was woefully inadequate and too loud for my taste. Out came the gas engine and transmission and up it went on craigslist.

In went a ME1003, Alltrax 7245 and a 16S CA100 pack. This was the kart when it was set up for 48V.







My friends and I often drive it at a large outpatient surgery parking lot (after business hours). We set up auto-x style courses and race each other for time, its lots of fun but quite stressful on the overall system as it sees high load and short cool down periods. It gets driven pretty hard. Sliding into curbs, spin outs, locking up tires under breaking and an occasional collision with a tree or post is not out of the ordinary for this thing (the astute will notice the front fender is slightly crooked from an overzealous operator). The battery pack and motor have seen lots of high duty cycles. That being said, I have had no complaints about either and before the motor died, the 48V setup had about 30hrs of use, plenty of which was at 100% throttle.

Here is a video of it in action a few days before I killed it.

http://www.dailymotion.com/video/x2i2ycu_e-kart-snow-runs_auto

Some of the carnage evident after opening the motor case.

Are those the stock hubs letting you bolt those wheels on?

You do remember the motor I suggested, right?

This is the most mind blowing whatever thing I've ever seen on ES. I have thousand of questions. Let's see how it's going on step by step.
For starting with something simple, what kind of battery chemistry / format are you ponder on the next 72V build? Also what performance / specs are wanted?
How is the life expectancy of the current battery?

Budget is a large factor for this project as I'm concurrently building a LR mid-drive bike =) Since I already had 16 CALB cells for the 48V setup, I just added 8 more to achieve my 72V pack. If I could do it all over again, I think I might have used a Leaf kit @ 96V in conjunction with that PM AC motor you suggested Dauntless. There is no doubt that would be a superior set up, albeit a few more coin.

Here is the kart in its current state, awaiting juicy new parts! You can see the spacers on the front hubs. The rear hubs have adapters from adapter kings to fit the atv wheels I have, the resulting lug pattern is 4 x110 all around. Initially it had 4x110 fronts, but 4x137 rears.



The Aluminium motor bracket is from electricmotorsport, it is a beautiful piece. Very lightweight and the powder coat is a pretty color, it just isn't showing up well in the low light conditions of my garage.



A few new sparkling clean pretty pieces of metal soon to be installed! New rear brake caliper, pads, rotor and axle bearings.



I have started welding up the new battery tray, 16 vs 24 cells.
The green stuff on the 16 cell tray is yoga mat material. I used it to improve static friction and act as a buffer between my precious cells and the angle iron.
Yes, I know my welds are ugly, but I'm still learning the art =)

Nobuo said:

This is the most mind blowing whatever thing I've ever seen on ES. I have thousand of questions. Let's see how it's going on step by step.
For starting with something simple, what kind of battery chemistry / format are you ponder on the next 72V build? Also what performance / specs are wanted?
How is the life expectancy of the current battery?

Click to expand...

To stretch my dollar, I'm just adding cells to my pack. I have read and heard conflicting statements on what these cells will healthily discharge, so I don't feel any predictions I make will be accurate. The calb cells come in at 180lbs for all 24 and in the back of my mind I wonder how a smaller lipo pack would perform. I would like to eventually enter the kart in an auto-x event and I'm thinking some 18650 cells in a 20S 8p configuration would be something of a lightweight (~20lbs) 'track' setup capable of a few laps. The kart honestly feels heavier than I'd like, at its 48V setup it weighed ~530lbs. If I could knock +100lbs off, I think the results would be dramatic.

If I fit turn signals, reflectors and a windshield/wiper I can register it as a low speed vehicle for some road use, however it is primarily a fun project. As such I'm defining the performance in terms of top speed and acceleration. Supposedly the ME1003 is capable of 11.5kw continuous and 23kw peak. I believe the kart should be right around the 600lb mark when its 72V conversion is complete. Unfortunately I never conducted any timed acceleration tests @ 48V, but I did race a 420cc Yamaha KODIAK ATV and it was even to about 29mph which was the kart's Vmax. At 48V the ME1003 was turning ~2000rpms. At 72V I've read it will turn 2800rpms loaded, which should give me 41mph without gearing adjustments, we will see.

Yes, You would save some space and weight with 18650 lithium-ion cells. But also do some records in power, range and efficiency.
For make some real numbers, eg. a little 20s10p with the classic top quality panasonic NCR18650PF would be something like this.

- a dimensions of 320mm x 190mm x 70mm spot welded nickel and wrapping included
- 9,1Kg (20lbs) also welding and wrapping included
- 29Ah 72V 100A máx continuous. Only 7,2KW máx continuous, but you can think that a pair of this packs will do 14.4KW, three 21.6KW, etc. / make a bigger one / use high C discharge cells like Samsung 25R that could do with this small pack 350A máx continuous, 25KW and being reduced slightly to 25Ah.
- costs in all materials included around $700 with panasonic cells.

Posibilities are broad in shapes, specs and prices if you mess with 18650

I like the Samsung 25R, however my welding skills are not up to the task of creating a pack out of 18650s. You are right, the weight savings would increase the karts braking, turning, acceleration, range and power consumption. Maybe I should just put these prismatic cells in an electric tractor and start over :lol:

Hub adapters. Never thought of that. Same bolt patterns I find on so many of those karts. The front would take old RX7 wheels, never found anything to match the rear.

Just reminding on the motor in case this one doesn't prove salvageable.

Yeah Nobuo, this thing blew my mind a few months ago. Maybe someday he'll have money for kewler batteries and the like. The great limiter.

So true, money is the limiting factor . . . ok money AND my welding skills are the limiting factors :lol: . I think the proper version of my build would involve a ME PM AC motor, a 550A servcon gen 4 and a pouch or 18650 pack. Put those goodies into an Aluminum golf cart frame and rebuild the rear end with an ATV rear diff and IRS. That would be 10 classes of excellentness above my project. It would cost you as well and at that price point it would be tempting to not just build a street car instead. I would like to see something like that done: more torque, half the weight and twice the rpm

Hoping to fit these in my new tray this weekend.


QET charger came in.



Few other bits and bobs. I'm powering my low current circuit with the 4S lipo.

We both know money is the limiting factor... but if you suddenly get a couple hundred dollars free, theres a guy on here taking apart a Tesla battery pack... a bunch of those cells would be perfect.

It's easy to over engineer a fun kart.
You have an excellent base vehicle with lots of potential to go faster, weigh less, ...and spend more money !
Unless you are intending to go off road competition, a differential and IRS won't give you much advantage.
Some of the fastest vehicles round tracks like Laguna etc , are ICE karts with solid axles and chain/sprocket drive.
Also a standard DC Brushed golf kart motor is capable of huge amounts of power....if supported by a suitable controller and battery pack.
For fun/track /off road use it's hard to justify anything more sophisticated than a bunch of RCLipo for power/weight/ cost balance, and ease of assembly .

Hillhater said:

For fun/track /off road use it's hard to justify anything more sophisticated than a bunch of RCLipo for power/weight/ cost balance, and ease of assembly .

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I think you're exactly right. In my ignorance, I gave more consideration to pack capacity than pack weight and that just isn't befitting the nature of the project. In a vehicle this small, a pack with higher energy density would be more suitable. I'll post pics when I get the tray mounted, but 24 of these prismatic cells are just barely going to fit in the largest available space on the frame(where the passenger seat would normally go).

For Dauntless:

Hub modification in all its glory


Something about the contrasting texture of steel and aluminium I find pleasing to the eye.

I think you'll have problems with the knurled studs twisting in the aluminum holes when you attempt to loosen the lugnuts.

major said:

I think you'll have problems with the knurled studs twisting in the aluminum holes when you attempt to loosen the lugnuts.

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That depends on if he made them himself or if they're commercially available. I think word would be out of that problem if these are storebought, I sure don't hear of that happening. I had adapters on a '92 Mustang several years back and had no problems. Though if he used, say, 6061 T6 aluminum as the commercial adapters do, it'll be fine if he made the holes right.

And yeah, they're beautiful. A shame to cover them with the wheels and tires, eh? But then you could get some nice ones there, too.

major said:

I think you'll have problems with the knurled studs twisting in the aluminum holes when you attempt to loosen the lugnuts.

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If it's done right, they will never spin loose. They make hundreds of thousands of them every year. Sports cars, drag cars, Trucks, jeeps, atvs... they all have them. Just drill a hole and press the wheel stud in.

http://www.amazon.com/dp/B007CMV9QS/ref=dra_a_rv_sc_hn_it_P1400_1000?tag=dradisplay-20&ascsubtag=c811c6cd701a91c7fff026a6b6caf855_S

Dang, if I could get my hands on one of the used ones that pop up on Craigslist around $600, or less if they've blown the engine up, this could all be great fun. Not sure I want to buy a new one to get started.

For anyone considering a Chinese kart conversion, here are my musings from a year or so involvement in their respective milieu:

Despite the many different names and model numbers, there are fewer unique configurations of these off road karts and I suspect they're all manufactured in China. Some of them, like American Sportworks, are assembled in the US and elsewhere, but I wouldn't be surprised to learn that all parts come from the same factory. After a long while of searching and measuring, I concluded that there are 3 main classes of karts:

The smaller variants are intended for children and aren't really suitable for adults. These usually sport a 110cc, 125cc, 163cc or 200cc (OHV style) engine. They are lightweight with thin frame tubing, small diameter wheels, soft suspension and small brakes. They are by far the most inexpensive. Its unlikely that one of these would support a 23kw powertrain for very long.

The mid size kart, like the one I have. Its defining feature is its Honda GY6 150cc clone motor usually mated to a CVT of some sort. These are the most prevalent design and have entire web forums dedicated to their existence (buggynews). These karts are larger (~500 lb curb weight), more robust and fit full sized persons with ease. Many of the parts are interchangeable between the 150cc variants. This makes conducting a rebuild quite easy (and cheap!) due to the abundance of replacement and aftermarket parts.

The larger karts, utilizing 250cc-1000cc engines. These are much heavier (~1/2 ton), more expensive, are available with seating for 4 and titled for road use in some cases. I believe a common name for a design in this class is the 'sand rail'. They are more akin to dune buggys than go karts, as such they carry a hefty price tag.

I once considered purchasing from a vendor in California (killermotorsports) who offered some of his inventory sans powertrain at a discount. It would have been a special order affair, but he was the only one I came across who would offer a new roller. He has a pretty large inventory with most of the current styles available for purchase.

Battery tray is about half complete, pack fitment is tight.




Old gritty bearings out, new silky ones in! General clean up of bearing carrier and dust covers was an OCD dream come true.




Overhaul of rear axle is now complete, awaiting reinstallation.

Its going on!

How do you stick the batteries each other?

How much Ah are installed now?

They are 100Ah cells. The pack will be secured via CUNTS (Cell UNiform Tensioning System)

So THAT is why they're in the passenger seat. I always wondered where that "Term" came from.

electron bom said:

They are 100Ah cells. The pack will be secured via CUNTS (Cell UNiform Tensioning System)

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I wish I could like posts here. :lol:

MrDude_1 said:

I wish I could like posts here. :lol:

Click to expand...

There is ONE way.

http://endless-sphere.com/forums/viewtopic.php?f=1&t=593

I was able to spend a little time this weekend on the kart. I'm hoping in another weekend or two it will be drivable.

New brushes arrived!



Looking a little more complete.



This is my attempt at a fine adjustment chain tensioning screw.