# Electric Kart "Sparkplug" Build Thread / Discussion



## lostinspacebar (Mar 4, 2011)

Hi,

I've been planning/building an electric go-kart. The current BOM is at: http://goo.gl/kStlS

The biggest questions for me is the battery system. I am pretty sure I am going LiPo because of the weight savings. I went with the electricmotorsport site because it has everything in a nice index. Not necessarily going to buy from them. The battery pack selected has a 72V LiFe pack and a BMS and a charger. Is this worth it? 

I was looking around at stuff like MiniBMS. But wasn't sure if that'd be ok. I'm fairly comfortable with electronics/batteries etc. but I'd rather go somewhat safe than super cheap.

The only think I HAVE bought so far is the kart frame (wheels aren't in the pic, but they are about 10-11" in diameter):









What do you guys think? Any suggestions? Comments? I hope to use this place as a build log to keep myself working on the project.

- Aditya
www.lostinspacebar.com


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## Salty9 (Jul 13, 2009)

Looks like it's going to be a fun project. With such a small footprint knitting together the bits and pieces will be a challenge.


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## frodus (Apr 12, 2008)

Not sure if you could fit it, but I have a K91-4003 for sale.... we were going to put it in a go kart. TONS of torque.... hardly any use. Got a Contactor too. There's also a guy on elmoto.net that has an alltrax as well, for $1000 you get motor/controller. MIGHT be able to help with batteries, depending on what you want to use.

The list looks good though, should be super fun!


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## esoneson (Sep 1, 2008)

Don't know about the rest of you folks, but if I tried this build on hardwood floors I'd be in deep do-do with the Misses.

This looks like it is going to be a great fun project. Good luck!

Eric


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## EVKarter (Jun 22, 2011)

I will say this much, you bought a decent kart to start off with, so good job there. Looks like an older pre-wildkart TrackMagic? The brembos will help slow this 500lb projectile down for sure. TM's arent made any more, so it can be harder to get parts for them.

I plan on EVing mine at some stage, but time and budget has put things on a hold. I don't have $4K for two seasons, let alone an EV project LOL.
Here's my thread, hopefully it will be of some help: http://www.diyelectriccar.com/forums/showthread.php?t=60039


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## lostinspacebar (Mar 4, 2011)

@Salty9: yeah. It should be interesting. It's a learning experience unto it's own - trying to get things light/cheap.

@frodus: Thanks for the pointers. I don't know if that motor is all that attractive. I've read DC motors ARE better for longer life since they don't melt or something if you run em too hot for long. But I think I'll still try to take my chances with this for the 30+HP  The other site looks cool though. Always looking for more places to find used stuff 

@esoneson: Thanks! Also, Single. Apt. Cheap linoleum floors 

@EVKarter: I've actually been reading your post already. Was looking for previous projects to learn from any pitfalls etc. Lots of awesome info there. Are you still building yours? Your requirements/final product seem very close to what I am trying to build.


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## frodus (Apr 12, 2008)

lostinspacebar said:


> @frodus: Thanks for the pointers. I don't know if that motor is all that attractive. I've read DC motors ARE better for longer life since they don't melt or something if you run em too hot for long. But I think I'll still try to take my chances with this for the 30+HP  The other site looks cool though. Always looking for more places to find used stuff


No problem, figured I'd help if I can. Lots of people use series wound due to their thermal mass (you'll likely need to force air cool your Mars motor due to overheating), as well as their lack of magnets and more torque per amp of most anything available. Note: My motor is rated for both continuous and peak, but websites list continuous. It's a 30+HP motor and you can get brushes at a forklift shop.


I'm not sure if I misunderstand you.... but they're both DC brushed motors. The only noteable difference is magnets in the rotor, so be careful with overheating.


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## lostinspacebar (Mar 4, 2011)

frodus said:


> Note: My motor is rated for both continuous and peak, but websites list continuous. It's a 30+HP motor and you can get brushes at a forklift shop.
> 
> 
> I'm not sure if I misunderstand you.... but they're both DC brushed motors. The only noteable difference is magnets in the rotor, so be careful with overheating.


Ah, I found another website that listed peak HP. It's still less, but I guess it might enough and be cheaper. But yeah. Looking around.

And no, you didn't misunderstand, I mostly just didn't say things right I guess. I meant DC wound vs. perm. magnet. And I guess the perm. ones aren't as good at high load when it comes to heat. I'll have to keep that in mind. The Perm. ones tend to be smaller, but if I have to introduce a fan and such into the system, maybe the DC Wound will be cheaper/smaller/lighter.

P.S. EvKarter: The kart chassis is from a 2002 Trackmagic Diablo Shifter Kart.


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## frodus (Apr 12, 2008)

I tend not to trust Mars on that 1003.... there's no motor curve that I can find. Just keep an eye out for a motor curve.

Look at some of the other kart projects, lots of them use Series wound and even AC.


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## lostinspacebar (Mar 4, 2011)

The only datasheet I have so far is: http://www.electricmotorsport.com/store/pdf-downloads/emc-rt200_data.pdf

But as you said, not a lot of people have used them yet. I am looking more and more at this series wound stuff, especially if I can get a motor about the same cost (about $650) used. The wound one is a lot heavier though.


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## frodus (Apr 12, 2008)

let me know. I chose the K91 because of performance, then went AC.


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## Yabert (Feb 7, 2010)

Hi lostinspacebar

If you can put your hands on A123 20 Ah cells, you can build a powerfull 72v battery (24s = 76.8v or 26s = 83.2v nominal) able to give you 30-40 hp and who weight only 28-30 lbs.

If not, you can also find some Headway 38120 8Ah. They are easely availiable. 24s 3p (76.8v 24Ah) will weight 53 lbs.



I also have a nice D&D motor to sold (30-40 hp peak) : http://www.diyelectriccar.com/forums/showthread.php?t=56797


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## lostinspacebar (Mar 4, 2011)

Is 20AH going to be enough though? With my calculations in my spreadsheet, I need atleast like 40ah to get some reasonable time. 

Are my battery calculations off?


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## lostinspacebar (Mar 4, 2011)

So I went with the ME1003 and did a quick test with 2 SLA batteries. 

http://www.lostinspacebar.com/blog/2011/12/wiring-up-the-test-bed-mki-part-ii/

This page also has other updates on the kart if anyone is interested:
http://www.lostinspacebar.com/projects/sparkplug/build-log/

More updates soon hopefully.


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## winzeracer (Apr 3, 2012)

Hey there any updates?


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