# racing kart build help



## stonny9 (May 8, 2012)

*consider this build/thread closed. *

My brother was the one who put his foot in and was financing it after I mentioned electric and showed him a few builds and said lets build an electric kart.

Once he saw the estimated cost of $1,878 he cancelled the build even though from the beginning I told him it would be at least $1000. I shopped around a lot and this is as cheap as it could get with quality parts for this performance.

For anyone looking for a build this was my list most of the stuff came from ev-drives and thunderstruck. The batteries I sourced from someone local so that saved a couple hundred dollars. So if you dont have at least $2000 then your build probably wont happen.

Motor ME1003 $500.00 
Batteries LiFePo4 Headway 38120 8ah $10 each x 48 
Battery Holders estimated $60.00 
Controller Alltrax AXE7245 $450.00 
USB to RS232	$14.50 
Model ED250 Style Switch, with 1000 ohm pre-charge resistor	$27.00 
New PB-6 Curtis Original Throttle	$89.00 
72 Volt SW-180 Contactor with 3 Amp Diode and 1000 ohm Resistor $72.50 
Wire 6 AWG 30 ft	$35.00 
misc connectors	$150.00 

This is my first build and I am new to the ev world. Gonna be on an old kart racing frame with slicks. I have been reading for a month trying to find info on all the ev sites I could find. Finding used parts is very hard if not impossible without months of looking/waiting so I am going used cause I want more power than a bike but less than your typical ev.

Specs looking for are 8+ hp cont and 15+hp max. This is just a fun kart but want to stay around $1000 not including batteries. I am gonna use some free 7amp/hr batteries at 72v for now until I kill then switch to 4 12 amp/hr batteries @48v until they die also. So I know they will hold the performance back until I swap them out

Any and all input is welcome.

Cloud electric seems to be the cheapest and has most/if not all the parts.

Motors are narrowed down to these in order of my perceived preference of the most power:
ME0709	$485	BRUSHED	24-72V VDC, 125 amps Continuous, 300 amps Peak 1 Minute	http://www.cloudelectric.com/product-p/mo-me0709.htm

Recommended by someone on endless sphere but I dont think it meets my specs plus the controller is more exspensive.
ME4201	$394	BRUSHLESS	24-72V VDC, 90 amps Continous @ 48v	http://www.cloudelectric.com/product-p/mo-me4201.htm

ME0909	$374	BRUSHED	12-48V VDC, 100 amps Continuous, 300 amps Peak 1/2 Minute	http://www.cloudelectric.com/product-p/mo-me0909.htm

ME0907	$394	BRUSHLESS	CONTROLLER EXSPENSIVE	http://www.cloudelectric.com/product-p/mo-me0907.htm


Cloud has a package deal with controller but u only get about $12 off and they max at 300amps so package deal doesnt look so good. Shouldnt I go bigger on the controller so it isnt maxed with the ME0709? Like say a 400+ amp controller. Plus if I ever go with a bigger compatible motor in the future I would like to not have to buy a bigger controller.

Looking at Kelly or Alltrax.
Is regen or reversing worth it? I dont understand the specifics of making them work yet. Regen benefits seems a moot point though.

Some type of emergency disconnect like an Anderson plug style?

EDIT: I found a nice diagram from alltrax on another build thread 
http://www.alltraxinc.com/files/Doc100-081-A_DWG-AXE-PermMag-no-Rev-wire-dia.pdf
and the site with all of their documents
http://www.alltraxinc.com/Doc_Depot.html


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## stonny9 (May 8, 2012)

I cant seem to find any info on all parts that are needed. If someone could tell me what I need that would be great.

Probably gonna get this motor.
ME0709	$485	BRUSHED	24-72V VDC, 125 amps Continuous, 300 amps Peak 1 Minute	http://www.cloudelectric.com/product-p/mo-me0709.htm

With this controller.
Controller Kelly Programmable 24-72 Volt 300 Amp PM & Series KDZ72300
http://www.cloudelectric.com/product-p/co-kdz72300.htm

What throttle do I need? Already have a pedal so I dont need a whole pedal assembly.

Guess I need this for a switch?
Port Panel Key Switch, Fuse, Charger Plug
https://www.cloudelectric.com/ProductDetails.asp?ProductCode=CP-260-14&CartID=3

Dont I need a contactor and/or solenoid?

The wires I can get locally from somewhere.


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## Woodsmith (Jun 5, 2008)

I can't help with much of that but you will need a main contactor to make/break the connection to the pack.
That will need to be able to break the voltage and the current that could be drawn from the pack in case of controller failure.

Depending on budget you could get a contactor from a suitable forklift truck dismantler or buy a Kilovac sealed unit.

You will also need a fuse for the pack. It should be rated for the voltage of your pack and the maximum current. A lower voltage fuse may melt but may not be able to stop the arc that forms.

A suitable charging plug can be as simple as an Anderson connector or something much more complex but that would be unnecessary on a kart.

A key switch is a personal choice. Are you likely to leave it where others can jump in and drive off?
I have removed the 'ignition' keyswitch from my tractor as it was getting in the way. I have two battery isolator switches with removable red keys instead. I may refit a smaller key operated on/off switch at some point if I decide to go to rallies and shows.


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## stonny9 (May 8, 2012)

I have the parts narrowed down to these if I am correct. A couple parts are different variations as I dont know what to get. I am thinking just have the emergency disconnect and anderson style plug. Then I could do away with the key. I believe I would then need a throttle with no switch. At least according to the diagram.

Wiring should be 6awg according to the online calculator of 6ft @ 2% loss 300amp max draw @72v 

Motor Motenergy ME0709 Permanent Magnet DC Pancake Brushed
$750.00

Controller Kelly Programmable 24-72 Volt 300 Amp PM & Series KDZ72300
$0.00

USB Cable for Kelly Controllers
$29.95

Fuse ANE 300 Amp
$5.95

Resistor 1000 ohm Pre-Charge for 60-72 Volt Contactors - 3/8" Terminal Ring
$3.95
or 
Resistor 1000 ohm Pre-Charge for 60-72 Volt Contactors - 5/16" Terminal Ring
$3.95

Throttle PB-6 Type 0-5K with Micro-Switch
$69.95
or
Throttle PB-5 Type 0-5K Lever without micro-switch
$74.95

Diode 3 Amp Contactor Coil Suppression for 72V Solenoids
$3.49
with
Contactor PTX 200 Amp 72VDC Coils SW180 Type On/Off
$59.00
and/or
Emergency Push Button Switch
$89.99


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## CrazyAl (May 9, 2011)

stonny9 said:


> Looking at Kelly or Alltrax.
> Is regen or reversing worth it? I dont understand the specifics of making them work yet. Regen benefits seems a moot point though.


In my opinion, reversing is worth it. I've done an Electric Go Kart Conversion and it does not go reverse. Very inconvenient and I end up having to get out and push the kart reverse every time I want to go reverse.

In my opinion, regen is worthwhile if you are going down a lot of hills or doing a lot of braking as it can help extend the range, hence, fun of driving your kart. It also helps reduce brake pad wear. Just bear in mind, if the batteries are fully charged, regen will not activate and if the current generated by regen is too high, the controller may choose not to perform regen - need to read the manual as each controller handles these situations differently.


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## stonny9 (May 8, 2012)

Woodsmith said:


> A key switch is a personal choice. Are you likely to leave it where others can jump in and drive off?
> I have removed the 'ignition' keyswitch from my tractor as it was getting in the way. I have two battery isolator switches with removable red keys instead. I may refit a smaller key operated on/off switch at some point if I decide to go to rallies and shows.


I will always be around it. Maybe just an emergency disconnect like a panic button or safety lanyard to shut off when bailing like a waverunner and an anderson plug for a direct connect/disconnect on the batteries? Regardless of any scenario I would always have the battery's unplugged when not in use.

Could I then do away with the solenoid? Or does the controller need a signal to turn on besides the main power being turned on.


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## winzeracer (Apr 3, 2012)

stonny9 said:


> I will always be around it. Maybe just an emergency disconnect like a panic button or safety lanyard to shut off when bailing like a waverunner and an anderson plug for a direct connect/disconnect on the batteries? Regardless of any scenario I would always have the battery's unplugged when not in use.
> 
> Could I then do away with the solenoid? Or does the controller need a signal to turn on besides the main power being turned on.


Stonny,

Looks like you have got a great start. I am not going to have a key either, no real need for it. For an emergency disco I was going to do a heavy duty kill switch but it turns out they are $100+ so I will have a physical disconnect, i was alternatively thinking about a male and female connector that each had a small electro-magnet(home made) with a switch on the or near the steering wheel that would kill the electro-mag and thus disconnect the power.

I was also wondering about the need for the solonoid, between the battery and controller. It looks like it is a Normally Open contactor that only closes when the throttle is depressed, for safety. I am still deciding on a few options that will affect wiring so I have not done too much research on if this contactor is really needed. 

Notice here ----> http://www.alltraxinc.com/files/Doc100-046-A_DWG-AXE-Reverse-No-PlugBrk-wire-dia.pdf

That the precharge resistor is connected to the input and output of the contactor in question. I think this has to do with the need for this contactor. I am sure someone with more knowledge will clear this up.

Brock
www.winzeracer.com


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## stonny9 (May 8, 2012)

winzeracer said:


> Notice here ----> http://www.alltraxinc.com/files/Doc100-046-A_DWG-AXE-Reverse-No-PlugBrk-wire-dia.pdf
> 
> That the precharge resistor is connected to the input and output of the contactor in question. I think this has to do with the need for this contactor. I am sure someone with more knowledge will clear this up.
> 
> ...


Now that you mention it I remember reading on either alltrax or kelly site that the precharge resister is needed to keep the capacitors(or maybe something else) in the controller charged up so when power is applied so there isnt a huge inrush of current. Having the correct precharge is necessary for controller life/longevity. I think I will just go with a contactor to K.I.S.S.

I have one emergency kill button picked out and the kill switch lanyard that I have selected I notice connects to a contactor.


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## stonny9 (May 8, 2012)

consider this build/thread closed. My brother was the one who put his foot in and was financing it after I mentioned electric and showed him a few builds and said lets build an electric kart.

Once he saw the estimated cost of $1,878 he cancelled the build even though from the beginning I told him it would be at least $1000. I shopped around a lot and this is as cheap as it could get with quality parts for this performance.

For anyone looking for a build this was my list most of the stuff came from ev-drives and thunderstruck. The batteries I sourced from someone local so that saved a couple hundred dollars. So if you dont have at least $2000 then your build probably wont happen.

Motor ME1003 $500.00 
Batteries LiFePo4 Headway 38120 8ah $10 each x 48 
Battery Holders estimated $60.00 
Controller Alltrax AXE7245 $450.00 
USB to RS232	$14.50 
Model ED250 Style Switch, with 1000 ohm pre-charge resistor	$27.00 
New PB-6 Curtis Original Throttle	$89.00 
72 Volt SW-180 Contactor with 3 Amp Diode and 1000 ohm Resistor $72.50 
Wire 6 AWG 30 ft	$35.00 
misc connectors	$150.00


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## winzeracer (Apr 3, 2012)

stonny9 said:


> consider this build/thread closed. My brother was the one who put his foot in and was financing it after I mentioned electric and showed him a few builds and said lets build an electric kart.
> 
> Once he saw the estimated cost of $1,878 he cancelled the build even though from the beginning I told him it would be at least $1000. I shopped around a lot and this is as cheap as it could get with quality parts for this performance.
> 
> ...



Bummer, was looking forward to seeing it come together. My build is at $3k, and still plenty of parts to buy. Though I am going to stay with the Alltrax.

Brock
Www.winzeracer.com


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