Unnamed Electric Go Kart Project [UEGKP]

[Cola_]

Hello once again my electric go kart aficionados!
Almost a year ago I came here asking about ESC's for a forklift motor go kart project and I'm back with documented progress!

We originally decided to build an electric go kart about a year ago, planning to race our friend who was going to build a racing mower with the same deadline as us. We planned to race this month but neither of us ended up reaching our deadlines in time. Nonetheless we still plan to race some day in the future!

After finally managing to rig up a gear onto the existing spline shaft from the forklift hydraulic pump, we got the go kart chained up and ready for power. Four batteries and some sketchy jumper cables later we managed to get 30mph out of our gearing setup! (It's geared more for torque than speed - small gear driving larger axle gear) At top speed you have very little control over it but it's definitely a thrill to drive. The kart only has one powered wheel and we thought about welding them back together but decided against it. We may have been able to get more stability over turning but we didn't want to go through the effort of possible broken welds and making sure they were lined up right.

We started with a $50 frame that was going to be a simple small gas powered project before the race challenge. Next came the motor. We wanted power, and lots of it. We ended up buying a 48v 8800w motor at a surplus store in our area, talking the price down to $190 from $250 without the pump attached. We later had to go back and buy the pump for the spline shaft that it had so technically we got the motor for about $220. Trying to get a spline was an ordeal in itself that lasted multiple months (in that time we welded on more steel to mount the motor and drilled mounting holes. I also got a sweet boat chair at a rummage sale that fit on the go kart nicely) . We eventually brought it to a machinist friend of ours who keyed the old spline for sprocket that we had.

Hurrah! It can come under it's own power! Break out the jumper cables!

We had it set up with jumper cables for quite a while before we finally decided to ditch the speed controller idea and go with a four speed, letting us move forward. (the cast aluminum fan was also shattered by being removed at some point but I wasn't apart of that and we haven't had heat issues so I let that go.)

It may seem like that wasn't much but with other side projects and other jobs, taking a year to get to this point in definitely justifiable.

Our deadline is now mid-September and we have some work to do! We just finished a chain guard and need to mount it and we are also working on a four speed manual voltage shifter since we don't have the resources or will to buy a $400 speed controller for our little project.

I'll post more as we get closer to a complete project!

As for the name, if we decide on one it will probably be some kind of dumb inside joke between us.

 

[Cola_]

Painting!
We went for a mix of silvery grey paint with bright yellow as an accent color!
Also got the motor mounted and the new seat. We salvaged part of the old seat to mount the new one and found that the cushions make pretty good knee pads for working on stuff. We needed to switch out the seat anyways since it needed to be moved back so we would actually fit on the go kart.
We still need to fix the flat tires though.

 

[Cola_]

Currently working on the shift-box.

 

[Cola_]

I have future plans to make the kart completely pedal controlled but until we finish the shifting mechanism that's on hold.

 

[Functional Artist]

Hey, Your kart's Lookin' good!

I did some work with "Voltage" controllers.

Actually kinda fumbled by way thru.

Maybe this will help.

Check it out. https://www.youtube.com/watch?v=Jx7pj3ule0Q

https://www.youtube.com/watch?v=c7q2Lq0P604

https://www.youtube.com/watch?v=aQyXTau2olY

https://www.youtube.com/watch?v=_5EK9EOulsY

Basically, to make a long story short, it will functionally work but, It's very hard on everything.

The PM motor I was working with produced 72 RPM's per volt of input.

So at 12V input (first gear) the motor RPM would go from 0 to 864 RPM's immediately then (second gear) 24V would jump to 1,728 RPM's in milliseconds then (third gear) 36V would jump to 2,592 RPM's just as quick & then (fourth gear) would jump to 3,456 RPM's.

I stretched the chain & bent the motor mount on the first test drive.

I have discussed this in depth with moderator Sid (that guy's great)
check out the Manta Motor Controller Issues thread.

 

[itsid]

We had it set up with jumper cables for quite a while before we finally decided to ditch the speed controller idea and go with a four speed, letting us move forward.

Ohboy..ohhhboy.. ohboyohboyoboy..

you are asking for trouble.

Please do yourself a favour and check Functional_Artists ELDingo thread

short story:
he went with the sellers advice and made a voltage controller (the coolest slide contactor I've seen)
stretched his chain, bent his motor mounting plate because of the "hard shift" and now just bought a speed controller, since this concept is NOT working well for motors above a certain size.

And yours -although smaller than his- is still above that size I'd say.

Maybe because your kart is a one wheel peel atm (you must fix that btw) that all jerking is put into wheel slippage and thus doesn't affect the drive train or kart too much; but in the end it's still a bad idea.

Now: you have a live axle kart.. nothing was ever welded to that axle and nothing ever should be!
there are keys preventing the hubs from rotating,
three in your case.. one on the sprocket hub and one per wheel hub.
One wheelhub's key is likely sheared or missing.
Fix that, otherwise the metal on metal will eat on the axle and render it useless..
and with the power and weight a tiny bit of dirt is enough to eat the axle down enough for it to break
(and loosing a wheel at speed isn't a nice experience)

'sid

[EDIT]
Oh see.. I was too late
THAT!