electric go kart help

[whocares]

hello world!

im interested in building an electric go kart. im not looking for speed (10-15mph should suit me) but im a bit stuck in looking for the right motor and battery/ies to go with it for cheap, thus some help would be appreciated!

ive been keeping my eye on this motor, would it be any good?

id better mention that i have had NO experience with working with go karts or anything like this. at all. ever.

 

[Mackey]

Hey, I think we have about the same amount of experience in building (If that makes you feel any better), but I've been doing similar research for a couple of weeks now. I think that motor will be slightly underpowered, even for A light weight kart, and that you'd be better off with something more like 500w.

 

[whocares]

ah ok, ill keep searching then. glad to know that im not alone lol

 

[Mackey]

Well, I'm doing exactly the same thing at the moment and I heard this one is pretty good;

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=150373360386&ssPageName=STRK:MEBOFFX:IT

When I say I've heard, I mean people have told me. I have also bought it, but not tested it, so it better be good

 

[oscaryu1]

Decent motors, but overpriced.

 

[whocares]

looks like a decent motor, but yeah, its a bit expensive. also, id rather stick to a lower voltage, as batteries can get expenisve

okay, i have another quick question: does a potentiometer/variable resistor control the speed of the motor? if so where would i wire it in my circuit?

would this one be good enough for a 12/24v circuit?

EDIT: is this motor any better? i want to keep it 24 volts maximum.

EDIT 2: how would i wire the circuit as to turn the motor in reverse when a switch is flicked?

 

[Smurph]

I can help you a lot with the circuitry as I have had many college/university classes in Electric Engineering.

I think that potentiometer is set up to handle 1amp, maybe 2. You'll be pulling about 15, and will fry that really fast.
Try this one. It will hook right on in!


http://www.raylucke.com/20010926/tools/amps.phtml

You'll also want a 15 amp fuse. I know the item I linked to has a "failsafe", but you'll be way happier spending a small amount on a new fuse rather than a large amount on a new motor or controller. The fuse will fail-and permanently open the circuit until you change it-at a load greater than 15 amps, and will prevent damage to your more expensive items (batteries, and motor).

 

[whocares]

atm, this is going to cost £87.29 (if i buy everything off ebay) :O it will definitely cost more than i thought anyways. however, i will check a local scrapyard to see if i can get any useful stuff.

just checking, is this a list of everyting i need (exc. chassis, steering wheel, seat etc)
motor
belt thingy (should match )
battery/ies
speed controller
on/off switch
PTM switch

quick question: how does the speed controller control speed? from a quick glance at the circuit looks like you just switch it on and it powers away without you.

also, do you just wire the batteries up together like normal? i read on some other site that you have to have some switch arrangemet OR IT WILL BLOW UP lol

EDIT: another quesion about the battery - can anyone point me to a rechargeable battery WITH charger, or does any charger work for any battery?

 

[Smurph]

The PTM switch might not be necessary, or maybe I'm missing what you're using it for...

The toggle switch is only good for 10amps, and you'll wanna put 50% more than that through it at top speed. try one of these.

You hook your battery, motor, and potentiometer up to the speed controller in their respective positions (refer to the diagram). Then install the potentiometer that comes with the speed controller to the "gas" pedal. You'll want to be very meticulous on this part, and ensure it works properly. As you turn the potentiometer (which the pedal should do for you when you press it) the power given to wires that are going to the motor will increase.

It's not quite as simple as just putting one variable resistor in line, it requires other components to keep the circuit stable during the change. That's why you need to use the motor controller.

Depending on your kart frame, you might need get a good spring to return the pedal.

 

[r_chez_08]

batterys are cheaper on rapid online and they have free postage on orders over £30. they also sell toggle switches and ptms. here are some suitable chargers.

 

[whocares]

The PTM switch might not be necessary, or maybe I'm missing what you're using it for...

the PTM switch was supposed to be for the pedal, but you've told me to use the potentiometer. now im confused . is there some sort of button or...?

You hook your battery, motor, and potentiometer up to the speed controller in their respective positions (refer to the diagram). Then install the potentiometer that comes with the speed controller to the "gas" pedal.

the wiring would be easier than i thought then

batterys are cheaper on rapid online and they have free postage on orders over £30. they also sell toggle switches and ptms. here are some suitable chargers.

the 3.3aH battery here looks good. ...what does 3.3aH mean anyway lol
rapid dont seem to sell any rechargeables.

 

[r_chez_08]

ah- amps per hour i think, so a 3.3ah battery will last for 1hr with a 3.3amp drain. those batterys are echargable(i hope!), and the ones i am using to power my karts headlights (5ah, same price as 3.3ah!)

 

[oscaryu1]

ah- amps per hour i think, so a 3.3ah battery will last for 1hr with a 3.3amp drain. those batterys are echargable(i hope!), and the ones i am using to power my karts headlights (5ah, same price as 3.3ah!)

Those will last about 15 minutes lol. 5aH's are tiny. Hopefully you're going LED's.

 

[Smurph]

Yep. Ah = Amp Hour. At 15 amps, you'll last (AH/Amps) hours. Where AH = your AmpHour rating on your power source and Amps is the current you're drawing.

You're going to most likely have two batteries in series (Rather than parallel), which means 6.6 AH at 15amp load 6.6/15 which is 0.44 Hours, or about 26 minutes of pedal to the metal fun.

 

[oscaryu1]

I can help you a lot with the circuitry as I have had many college/university classes in Electric Engineering.

I think that potentiometer is set up to handle 1amp, maybe 2. You'll be pulling about 15, and will fry that really fast.
Try this one. It will hook right on in!


http://www.raylucke.com/20010926/tools/amps.phtml

You'll also want a 15 amp fuse. I know the item I linked to has a "failsafe", but you'll be way happier spending a small amount on a new fuse rather than a large amount on a new motor or controller. The fuse will fail-and permanently open the circuit until you change it-at a load greater than 15 amps, and will prevent damage to your more expensive items (batteries, and motor).

Why worry about a potentiometer? They sell 3 pin "potentiometer" electric go kart foot throttles on TSC Scooters lol. I have one...

And it shouldn't really matter about how many amps the potentiometer will handle, right? It just tells what FET's to send the power through, my potentiometer/hall effect throttle uses tinyass 20 gauge or so wiring, no problems.. it's just connected to the controller.

3.3aH batteries will last you approximately 5-20 minutes, then leave you stranded. You'll want 7aH batteries with a 250-500 watt motor, then 9-10aH batteries with 500-750W motor, and 12aH with 900-1000W's, and 17-21aH with anything more than that.

They're all rechargeable, chargers can be bought on eBay. Anywhere from 24V, 36V, 48V, to 60V.

 

[Smurph]

Why worry about a potentiometer? They sell 3 pin "potentiometer" electric go kart foot throttles on TSC Scooters lol. I have one...

Didn't know that. I've never wired an electric scooter. That's the best option.

And it shouldn't really matter about how many amps the potentiometer will handle, right? It just tells what FET's to send the power through, my potentiometer/hall effect throttle uses tinyass 20 gauge or so wiring, no problems.. it's just connected to the controller.

The potentiometer doesn't matter with the motor controller, You're right.

3.3aH batteries will last you approximately 5-20 minutes, then leave you stranded. You'll want 7aH batteries with a 250-500 watt motor, then 9-10aH batteries with 500-750W motor, and 12aH with 900-1000W's, and 17-21aH with anything more than that.

They're all rechargeable, chargers can be bought on eBay. Anywhere from 24V, 36V, 48V, to 60V.

looking at 13.2 Minutes to drain your 3.3aH if you're pulling the full 15amps the whole time.

Why would you limit yourself like that? Aside of budgets, why wouldn't you always advise a 17-21aH battery if such a pack existed that is applicable to your circuit?

 

[oscaryu1]

Here's a setup, go buy, and then build:

http://cgi.ebay.co.uk/Electric-36-v...porting_Goods_Scooters_LE?hash=item439ae324cf
36V 500W Motor

http://cgi.ebay.co.uk/48V-800W-Brus...porting_Goods_Scooters_LE?hash=item2a01f2e93e
48V 800W Controller

http://cgi.ebay.co.uk/BB-BATTERY-HR...rElectronics_Batteries_SM?hash=item35a42cbf1f
BB 12V 9aH, I don't like BB, but they're cheap (x4 - Yes, FOUR - 12V x4 = 48V)

http://tncscooters.com/partsdb.php?type=ES
TNC Scooters 3 Pin Foot Throttle (Clips right onto controller)

http://cgi.ebay.co.uk/48V-Battery-C...emQQptZLH_DefaultDomain_3?hash=item3a53c0fdfe
48V Charger (220V! MAKE SURE THIS IS WHAT YOU WANT)



Done.

 

[oscaryu1]

Didn't know that. I've never wired an electric scooter. That's the best option.


The potentiometer doesn't matter with the motor controller, You're right.



looking at 13.2 Minutes to drain your 3.3aH if you're pulling the full 15amps the whole time.

Why would you limit yourself like that? Aside of budgets, why wouldn't you always advise a 17-21aH battery if such a pack existed that is applicable to your circuit?

Wire'd plenty here. When you're 14 and have nothing to transport yourself on, + speed demon = Fun.

A 250W motor is rated at about 15A. Double that under hard acceleration, and you've got yourself a power sucker.

17/21aH batteries are roughly 25-35 pounds. Your motor will be burnt to a crisp and magnets as good as cast iron when you're done going up a hill.

 

[whocares]

cheers for the link to the stuff. ill use the 12v 5aH batteries on rapid in a bid to save money and weight though. ill need four to power that controller though, pretty wasteful as i dont need the extra energy anywhere else

http://cgi.ebay.co.uk/48V-Battery-C...emQQptZLH_DefaultDomain_3?hash=item3a53c0fdfe
48V Charger (220V! MAKE SURE THIS IS WHAT YOU WANT)

the mains in blighty supply 240v, or will that be ok?

 

[r_chez_08]

talk about JUST getting the free post on rapid!