UPDATE: I will keep this page open, but for now on I am going to put new updates on the blog section and pictures in the picture section.
I have been trying to make a gas go kart electric since October 2008.
October 2008: I get a used Zooma 22cc 2-stroke go kart for my birthday. We pay $150 on Craigslist. It runs great and spews more pollution then your car.
It is fun to drive around, but very noisy and smells terrible.
I take the plunge and order parts for an electric system. I have put the parts list below:
-1 24v 500w electric motor by Unite. (Parts For Scooters, $54.95)
-2 12v 18Ah batteries from Universal Battery. (Battery Mart, $34.95x2)*
-1 24v 500w 30A. controller. (Electric Scooter Parts, $39.95, item SPD-24500 & paid for by friend.)**
-1 Bladez Throttle Assy. (Parts For Scooters, $24.95)
-1 24v, 1.8A. Battery Charger. (Electric Scooter Parts, $29.95 & paid for by friend.)
Plus shipping and handling on everything, with lots of help from friends.
*I actually bought mine at Electric Scooter Parts, but then found that they were cheaper at Battery Mart.
**If building this, do NOT buy the controller, it does not work for this application and is a waste of money. This is a mistake that I made. It is worth it to note that I live on a hill, so it might work for other similar uses. I suggest contacting the manufacturer for more info.
Still October 2008:
I took off the perfectly good 2-stroke engine to replace it with the electric one.
Using bolts and angle iron, I figured out a way to mount the electric motor on the go kart chassis so that it lines up with the chain. I will upload images for a better idea as soon as possible. I originally tried using wood, but it flexed too much and the motor kept torquing the chain.
Finally I got it to work. I hooked up a 9-volt alkaline battery to the motor and it jumped across the basement. (Until I got on.) During that time I was still waiting for the controller, so I decided to take apart the thumb throttle. Not my brightest idea. Turns out that it was spring-loaded and it takes about 3 tiny hands to get it back together. Needless to say, it took a while.
The controller finally came. I screwed it on to the chassis and hooked it up. I used the tab connections for the motor and battery, but soldered everything else. Then me and my family went on an Obama walk, and I didn't get to try the controller that day.
The Next Day:
I got up for school at 6:15 AM the next day, like normal, and drove the kart around the basement before heading off to catch the bus at 7. I'm not sure, but I think I tried it that afternoon.
October 31st, 2008
Drove the silent go kart around while dressed up as an inventor- had lots of fun, ate lots of candy.
Drove it a lot, let other kids drive it, everyone enjoyed it.
Gradually, the controller's performance started to degrade until that one night in late 2008...
I was going to go up and down the block before heading over to a sleepover at a friend's house. I got on, pulled the throttle, and began wobbling up the hill. About five feet in, there was a soft bang and the go kart stopped completely. I quickly flipped the battery disconnect switch off, then got out to investigate. I found that two of the four capacitors had exploded, violently blowing off the cover. I sadly wheeled the go kart back into my garage, feeling defeated.
A Few Weeks Later:
I tried to use the go kart without the controller, didn't realize how fast it could accelerate, got a large scrape on my arm. Not one of my best ideas.
November 11th, 2008
Ordered a new controller. 24v, 30A, 500w. Model number SPD-2404 @ Electric Scooter Parts. Got it for $39.95, + S&H. My parents paid for it. Went to Oregon for vacation with friends, then came back.
Later in November:
Controller came. I hooked it up and it seems to work OK, but now the charger doesn't work. We have an electric lawnmower with a charger... Hmm... (Written February 19, 2009, but now my mom is telling me to go to bed, so to be continued.)
Okay, so we decided to hook the lawnmower charger up by stuffing wires into the female bullet terminals. It seemed to work well, and it charged very quickly, but when I woke up in the morning, I disconnected the charger and shorted the controller charging wires together because I didn't know any better. There was a flash and some sparks, and the controller didn't work anymore.
That December, it snowed a lot and I was disappointed that I didn't get to try it out in the snow. I tried to fit the gas motor back on, but it wouldn't start, probably because of the cold.
Early January, 2009:
I order my third controller for just under $100 from Scooter Support. It is a reversable model and is rated for 30 amps, 500w and 24v. I also buy a key switch and a 25A circuit breaker to hook into the battery terminals. Once it comes, I hook it up with the go kart and drill more holes in the chassis to secure it. I hook the key switch up so that it will reverse. Now the potentiometer is giving me problems. I have to keep readjusting it. Eventually, I take the twist throttle off of my friend's electric scooter and use it. It works.
I keep hearing a weird scraping sound from the motor. One day, backing into the garage, I keep hearing the sound, and when I try the controller again, it only works in reverse. My mom calls the Seattle Electric Vehicle Association (SEVA) and one of their members agrees to come over after school. That day, I find it hard to concentrate on classes. The SEVA guy takes the controller apart and points out a cold solder joint, thinking that might be it. We apply solder, but it still doesn't work.
I order yet ANOTHER controller. This is a 80 amp, 24 volt, up to 100 amps intermittent controller from the United Kingdom company 4QD. (See links page for more info.) I am very impressed with the delivery time, because I am in Seattle, and I ordered the controller on Sunday and had it come the following Saturday. It is called the Uni-8-24. Once I install it with a slightly weird heatsink design, it works great. I at first control it with a turning potentiometer and then get a thumb throttle, which is a lot safer and more intuitive. It still works and goes faster than any of the other controllers. I learned that a motor can safely draw about 400% over its rated current for about one minute, so for a 30 amp motor, I would need a controller that is over or equal to 120 amps. That is why this controller didn't blow up like the rest. (Took me long enough to figure that out!) It still works great. Here is a picture of it without the cover:
Late April, Early May 2009
My charging system is a little weird. I call it custom-made to avoid calling it jerryrigged. It usually takes a few tries to get it working. Other than that, I found a much better way to mount the motor (which was actually my dad's idea.) Sometimes it can get annoying, but it is usually great. The neighbors like that it is not loud and smelly anymore. So do I. Hopefully my next post will be something like "Everything is still working great, and I figured out a solution for the charger." But, I guess it will be a surprise for everyone. Well, goodbye for now. I will post some pictures of the new configuration soon.
July 25th, 2009
So, I'm back, and as you have probably guessed, this post is not what I hoped it would be. My charging system still doesn't work right and my batteries are degrading in power. (Shouldn't they last longer than this???)
December 7, 2009
Brr... The temperatures are reaching 20 degrees Fahrenheit in Seattle. No precipitation though, so no snow. But, on the bright side, I am finally getting back to this ongoing project after about 7 months of inactivity. To replace my bad batteries, I took the batteries out of the lawnmower (don't tell my parents...) and stuck them on my go-kart. They are almost equivalent in capacity, and exactly the same physical size. I hooked them up, and the difference is amazing! I have to guess, but I think I hit 15 mph downhill and maybe 12 mph downhill. My new throttle (a potentiometer from RadioShack) is kind of weird to operate, but hopefully it is just temporary. I also ordered a battery meter off the internet, so I wont destroy these batteries like the other ones. (Oops...) All in all, things are finally looking up, and I can actually put a smiley emoticon at the end of this post. I will post new pictures soon-if I remember. Lots of homework in 7th grade! Goodbye until my next post. :)
March 16th, 2010!
Well, now i have lived through 2 millenniums, 3 decades, and 2 centuries. Just a fun bit of random info. Anyway, my newest update. So I have shorted out more stuff, made more mistakes and fixed more things since my last post. My most important news: I now have a good, solid charging system that cannot damage the controller. I have a cord with alligator clamps on one end, and bolt-and-washer connectors on the other. (from a car power inverter-to play movies, power laptops, etc.) It was a simple matter to hook it up to the charger and make it work very well. Now a full charge is really a full charge, with no new dramatics. So, I am happy to report, there will now be more smileys!
April 16th, 2010
So, guess what? Sparks. Smoke. Oops. Darn. Yup, there goes another controller, down the drain. However, I am looking forward to hooking up the new one better. I have also applied a new coat of red paint, much nicer than it was before.
My new controller came, I ordered the same kind, as I believe that the last malfunction was caused by user error. I have hooked it up very well, with no loose wires or possible shorts. I have learned the the importance of good wiring :D. I have also bought new charger connectors from Parts Plus (they are an awesome store and I live only a few blocks away) so I could have my inverter connectors back, soldered them on, and it is so simple that is works super well. I know that I have promised pictures before, but I will really do it now because I will go outside and take them RIGHT NOW! ¡Hasta luego!