Solar/ Battery powered Go-Kart

silent wolf

Not sure if this is the right section, please move if it isn't


Well, besides my research project I am doing, I wanted to do something fun.

I want to build/ create a electric powered go kart. I all ready have the frame, and modifying it to hold around 4 deep cycle batteries. I have 3 50*watt Solar panels I will mount as a roof. I need help though....

Does anyone know where I can get some sort of speed control? Also, how big of a motor would you think would power enough to go kinda fast?

I will probably start to make this a main project for me starting next week.

Comments, feedback, and Opinions welcome on anything, same with questions.

AntronX

Re: Solar/ Battery powered Go-Kart

Here: http://www.diyelectriccar.com/forums/ and http://www.endless-sphere.com/forums/

silent wolf

Re: Solar/ Battery powered Go-Kart

I am thinking maybe 5 hp motor or so would do it..... Thoughts?

Kamala

Re: Solar/ Battery powered Go-Kart

I think 1hp is about 750W. 5hp is 3.75KW. Using 3.75KW for 10 minutes is 625WH. Or, at 12V, 52AH. Keeping DoDC above 50% would require a 104AH battery. That's doable.

Charging the batteries at 5% of C/20 requires 10A. Assuming the panels/charge controller can deliver that current, it would still take about 4H for 150W of PV to recharge the battery.

Drive for 10 minutes, recharge under excellent conditions for a day and then drive 10 minutes the next day. Maybe.

I don't know how fast/slow you want/are willing to go. A less powerful motor will allow longer drive times.

And the weight (load) of the cart will affect how fast/long you can drive. You, the frame, the motor, transmission, batteries, panels, wheels, etc.

Just off the cuff calcs.

K

silent wolf

Re: Solar/ Battery powered Go-Kart

I have thought through some of that stuff, but not that in detail! Thanks for the info. I probably will be mounting ~4 batteries or so, I know the solar panels won't do "that" much but it will do something. I am going to try to make this as efficient as I possibly can. It is just a fun project to do.


I would like to do around 20 MPH max... I have no idea what I need for motor power.

Is it possible to have 2 motors? Would that be more efficient, or just suck twice as much power?

mike95490

Re: Solar/ Battery powered Go-Kart

I'd consider AGM batteries, I know it's hard to roll a kart, but if you do, you don't want fluid acid all over.

BB.

Re: Solar/ Battery powered Go-Kart

There are two ways to go--One is to define how much power you will need, then setup the battery+power pack to meet those needs.

Another is to define how much power you have available and how fast you can discharge it without damaging the battery bank... At the moment, this is really what you are looking at. Generally, flooded cell deep cycle lead acid batteries are really hard pressed to output more than C/2.5 (2.5 hours to fully discharge). Some Concord AGMs can discharge as fast as C/0.25 or C*4 (15 minute discharge).

You can read about taking care of your Lead Acid batteries in this Battery FAQ.

Also, you may wish to look at alternative battery chemistry too:

Lithium Iron Phosphate Batteries; LFP; LiFePO4 discussions

There are lots of trade-offs to be made in the go-cart design... You will end up juggling several limitations in your power / motive system to obtain your optimum design.

-Bill

stephendv

Re: Solar/ Battery powered Go-Kart

silent wolf wrote: »

I would like to do around 20 MPH max... I have no idea what I need for motor power.

You could do that on a human power easy How about going for a recumbent bicycle design with electric assist, which can then be powered with PV + batteries... like these:

http://www.solartrike.com/
http://www.solarpoweredbike.com/

Slappy

Re: Solar/ Battery powered Go-Kart

silentwolf, here is a honest online dealer, http://www.cloudelectric.com/ ,ordered parts with no problem, a 5hp electric is equalivant to a 20hp gas,(in a nut shell), watch some U-tube vid's on electric go-carts to get an idea, from watching those vids, those little puppies haul "tail". on a side note, look up "white zombie" --->not a gokart but a street legal 1/4 mile EV-racer...... But the curtis controllers suspose to be great controllers, but cost more, but alltrax and kelly, are O.K. keep the controller in the battery voltage range, and a higher amperage range controller will send ya more juice to the motor.

Have fun with this project, and thumbs up!

silent wolf

Re: Solar/ Battery powered Go-Kart

Been looking around on ebay, I think I will buy this motor, and then a controller on Cloud Electric. http://cgi.ebay.com/ebaymotors/Traction-Motor-24v-9hp-_W0QQcmdZViewItemQQhashZitem3cab9e2c5cQQitemZ260577307740QQptZLHQ5fDefaultDomainQ5f100#ht_500wt_1182

Slappy

Re: Solar/ Battery powered Go-Kart

good HP but keep in mind, that the motor has brass bushings instead of bearings, keep that in mind, but when matching the motor to a speed controller, make sure it is for that type of motor, "as in brushless/ series/ PM" and of course the voltage. But, a 10 hp @ 72 volts will power a small pick-up for city driving. So a 9HP @ 48 volts on a go-cart, hummmmm.....thinking back......-->evil kenevil?.....when you mentioned a little fun, that will be a blast!

But please keep one thing in mind, have an emergency Disconnect at the drivers seat just in case of "wot" wide open throttle".

System2

Re: Solar/ Battery powered Go-Kart

The first, back in my day, were using car batteries and starter motors!

Few people realize what evil power lies under the hood of the lowly gas powered car. It isn’t the internal combustion engine whose power is merely fire contained but the starter motor, a direct tap into a fundamental force of nature.

The evil power of the starter motor is kept under control, harnessed to do our bidding, but do not underestimate it. It is the motor of supervillainy.

For many a child their introduction to this demonic device is not from the family car, even if their family has a car, it is from the world of soap boxes and go carts.

Every kid has a soap box car, little more than scraps of wood nailed and tied together with which they hurdle themselves down every hill in town. The thrill of the ride, no matter how short, fires the desire for more, a desire for motive power.

For the rich kids this was supplied by a Briggs and Stratton, for the middle class an old lawn mower engine might do the trick but for the kid from the family with push mowers those solutions were too expensive.

Enter the starter motor.

Every old car has one and for the lucky kid he might get one from an old Ford with 460 cubic inches of fire controlling engine. That starter motor with its simple relay control system is easy to adapt and most important it is cheap. That aspect of the motor, its low cost, will be just one of the promises all electric motors make but somehow never really deliver.

The cheap starter powered soap box becomes a go-cart and that means racing the rich kids with their shiny ICEs. All it takes is the drop of the flag and the flip of the switch to unleash the raw power of the starter motor.

The wheels spin, grab and throw the cart forward as though Thor himself was pushing. The acceleration is the first time that kid actually feels the whole seat pushing against him, feels a surge of addictive adrenaline and the evil power of the starter motor. The starter go cart always wins the launch.

Then the evil fails and the rich kid slowly putters off into the distance. Like a candle the Brigs and Stratton just keeps on flickering, pitifully, yet continuously, claiming a weak mocking victory.

But the Starter motor is like the blinding shock wave of a Supernova. It dumps all its power in one huge burst and promises more if only it could have its insatiable need for electricity fed.

Later that kid will learn the math behind his starter motor, that it is a DC series motor in disguise. When that kid learns the theoretical ideal limit of such a motor is infinite RPM, infinite Torque, and infinite Power, the evil super villain is revealed and seen as a potential tool for world domination.


In practice the path to world domination via a DC series motor is littered with the many pitfalls of friction, heat and internal battery resistance. Even when one gets a mount that will hold the torque of pure evil unleashed, feeding that evil creates a treadmill of every increasing heat sinks, cable sizes and battery banks.

The siren call of a series DC motor with a simple relay control system unleashing infinite power has been the downfall of many. The promise is so very tempting, so very aluring but I would suggest another path.

If one can break from the lure of series power I would suggest they take the lesser path of the shunt wound DC motor. In that motor the evil is diluted, weakened to a point that it becomes safe and easy to handle.

From there a step back into evil can be had with a compound DC motor. A motor that harnesses the hellish power of the series winding but is more suicidal than world dominating.

As one progresses through the various drive motors and controllers you will often be reminded that all these steps, extra windings and circuits are needed to control the evil power that resides in all motors.

An evil power the lowly and cheap starter motor is ever willing to release.

So maybe take advantage of the starter motor with it's built in gear system and easy to adapt ring gear but be warned, cheap power can have a very steep price. It can cost you your very soul. (not to mention many wasted hours and dollars trying to overcome it's limitations)

Kamala

Re: Solar/ Battery powered Go-Kart

Hafen,

Good post. I was going to comment on this a couple of days ago, but lacked initiative.

About 15yrs ago I took my kids to a "travelling" amusement park at a local Summerfest. One of the fellas there had a "ride on the train" set up. Paid the money and my kids got a ride on the tracks. You'd have to ask them if it was worth their time, they could not judge the value of money.

For my money, I asked the fella how his amusement worked. He lifted the "hood" of the "locomotive" and talked. As best I can recall the tracks carried 12V. The "locomotive" carried four down geared starter motors on each of it's four wheels. Gearing was the key.

This was not solar powered. Rather, a myriad of thick black cables snaked throughout the park area to the ubiquitous diesel generators that propound at sites of this type.

K

mike95490

Re: Solar/ Battery powered Go-Kart

Haefen wrote: »

The first, back in my day, were using car batteries and starter motors!
......

The wheels spin, grab and throw the cart forward as though Thor himself was pushing. The acceleration is the first time that kid actually feels the whole seat pushing against him, feels a surge of addictive adrenaline and the evil power of the starter motor. .....

All I ever built was a longboard - wheels off roller skates and mount onto a 2x4x6'

silent wolf

Re: Solar/ Battery powered Go-Kart

Doing some research, I am not going to go with that motor, seems as it wears out brushes after 5 hrs. of use.

Slappy

Re: Solar/ Battery powered Go-Kart

Haefen,, great post, and enjoyed reading, brought back mem from the child hood days, on nailing wooden go carts to gather, but on the starter part, those little puppies have some torque, here is a few pics of an push mower, made with a toyota starter motor, had a spare laying around, used a few seasons, and it worked well for the job, mainly used for trimming where the riding mower would not reach.
Attachment not found.
Attachment not found.
The white wire lying on the deck go's to the neg on the batt term held on by vise grip, and the white plastic tab with the spring is an fridge door light switch controlled from the mower handle. which in return controls the starter solenoid.
This was just a fun project, and I know it looks like junk, but it worked fine and got the job done, It got about 15 - 20 minutes use, before the batt would die.

but now using 48 volt craftmans push mower, and keeping it charged from the solar panels

notsobright

Re: Solar/ Battery powered Go-Kart

sounds like a fun and creative project! might consider using only three wheels for less ressistance with single motor and wheel in rear.

if you must have 4 wheels I would think twin motors would be the way to go.

I know the electric motorbikes have come alongway now and just last month we had the first ever electric motobike roadrace in the US and they were posting some pretty impressive lap times!

have fun!

silent wolf

Re: Solar/ Battery powered Go-Kart

Well, I am still trying to get all the materials, sorry for the wait. Do they make a dc to ac speed controller by any chance?