# Kokam Go-Cart (KoKart)



## major (Apr 4, 2008)

Just a short flick of first test in vehicle of a 14 cell, 40 Ahr Kokam pack. 

http://www.youtube.com/watch?v=QMa6c82dFGc


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## PhantomPholly (Aug 20, 2008)

Is that an F-86 tail in the background?


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## major (Apr 4, 2008)

PhantomPholly said:


> Is that an F-86 tail in the background?


Might be  I'm not an airplane guy. I'll ask. Just an old fighter jet sitting in front of the county airport where we're located. Thanks for noticing. So what about the battery 

major


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## Woodsmith (Jun 5, 2008)

That tree has nice colour leaves, sorta golden orange colour. Grass needs a bit of work though.


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## major (Apr 4, 2008)

Woodsmith said:


> That tree has nice colour leaves, sorta golden orange colour. Grass needs a bit of work though.


I'll talk to the grounds crew


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## PhantomPholly (Aug 20, 2008)

major said:


> Might be  I'm not an airplane guy. I'll ask. Just an old fighter jet sitting in front of the county airport where we're located. Thanks for noticing. So what about the battery
> 
> major


It looked like you built some sort of futuristic looking lexan box for it. Seemed kinda peppy, but I don't think it would be very practical commuting to work in a go-kart...


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## major (Apr 4, 2008)

PhantomPholly said:


> It looked like you built some sort of futuristic looking lexan box for it. Seemed kinda peppy, but I don't think it would be very practical commuting to work in a go-kart...


Ya know, sometimes it's better to start small and work your way up. As Bill Murray said "baby steps".


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## CroDriver (Jan 8, 2009)

This spammers are all over the place 

Anyway, I like the pack you built. I was looking for Kokams when I started to think about an electric car but they where very expensive at this time.

What is the price of the Kokams now?


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## ftaffy (Mar 13, 2009)

That looks vert cool, didnt know u could get EV Go Kart Chassis. I was looking at the DIY option for abit until i started a slightly larger DIY... Wish i had started the go kart as it would be damn bit cheaper.

Got any specs?
Motor:
Controller:
Battery:
Run time in anger:
Cost:
Etc?

When i can have this as my home EV go kart i will be happy:
http://www.youtube.com/watch?v=uQZpDmhnpoY
SAE EV, great fun to drive and works on roads... umm not that it was ever tested on anything but a race track.


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## Woodsmith (Jun 5, 2008)

It looks a cool ride and the acceleration is great.

Have you worked out speed and range with that pack?

I have also thought of taking a small step while converting my car. I might add a motor to my KMX trike or design a pusher trailer for it that I can also use with my bike.


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## major (Apr 4, 2008)

Woodsmith said:


> Have you worked out speed and range with that pack?


No, not yet. That was just a first run. We'd like to get it out to a real track and see how it holds up against the gassers. Maybe later this week or next.



CroDriver said:


> What is the price of the Kokams now?


Likely about the same as before. These were some surplus cells donated to the cause  



ftaffy said:


> ..... didnt know u could get EV Go Kart Chassis. ....Got any specs?


Chassis is home brew. 20 years old I think. Electric motor even older. Very much like a golf cart motor, except 2 bearings and keyed shaft. Series wound. Curtis 275 amp controller. A buddy did a RPM sensor and 9 volt battery circuit to shut down at 6000 so we don't blow the motor apart if the chain breaks.

Had 4 Optima red-tops on it for years. Those were about half dead. This LiPo pack comes in at about 1/4th the weight and should do better on range. Have yet to test for things like performance and range.

Cost = next to nothing, just a lot of time. Almost everything you see was lying around begging to be put to use. Just lucky to get a few Kokam cells donated. 

Regards,

major


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## major (Apr 4, 2008)

Here is a chart. Hopefully it gets attached to post. I've had trouble doing this before.

This is a discharge this we ran prior to sticking it in the cart. Our data computer wasn't working, so we had to "hand" read values and stick them into excel. But it gives the general capability at 2C. Temperature rise was only about 10F. 

Our BMS is not functional yet, so I don't think we were fully charged. Cells stayed pretty close, to about 0.01V. Charged to about 4.05 V/c.

Any comments (helpful, hopefully) are appreciated. We are rookies with this Lithium stuff.

major


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## major (Apr 4, 2008)

PhantomPholly said:


> Is that an F-86 tail in the background?


No, Charlie, the mechanic says it is a T-33, 2 seat version of the P-80, Shooting Star.


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## Wirecutter (Jul 26, 2007)

That looks like it's a heck of a lot lighter than my steamboat of a beast gokart. For those who have not seen it:

http://www.youtube.com/watch?v=9VLRjui3zvg

Now, because of the incredible weight of the Pb batts, I'm currently looking into lithiums. I'll post some test data in another thread.

Envy, envy. Sure wish I could get my hands on the quality of free stuff that you get...

-M


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## major (Apr 4, 2008)

Wirecutter said:


> Envy, envy. Sure wish I could get my hands on the quality of free stuff that you get...


Hey wire,

I made too light of it. It actually takes a lot of effort, time and work to get "free" stuff like this. And then there is the cost of draggin' it around with you for decades until you finally find a use for it 

And then some idiot comes along and wants you to reproduce it. Guess what? Half the stuff is obsolete. Oh well, you make do with what you have. You should see my barn  Anybody got a use for a pre-Curtis PMC controller, new in the box? Only 35 years of barn crud on the outside of the box. Just kidding  That is going into my museum.

Regards,

major


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## Wirecutter (Jul 26, 2007)

major said:


> And then there is the cost of draggin' it around with you for decades until you finally find a use for it
> 
> And then some idiot comes along and wants you to reproduce it. Guess what? Half the stuff is obsolete. Oh well, you make do with what you have.


I hear you. Now that I have space for junk, I find I don't throw anything away. Add to that the effect of all those times I threw something away and only *then* had a use for it.

-M


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## mrbigh (Dec 31, 2008)

Wirecutter said:


> That looks like it's a heck of a lot lighter than my steamboat of a beast gokart. For those who have not seen it:
> 
> http://www.youtube.com/watch?v=9VLRjui3zvg
> 
> ...


Cool ride !!


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## RoughRider (Aug 14, 2008)

the batteries are from victor from metricmind...right?


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## major (Apr 4, 2008)

RoughRider said:


> the batteries are from victor from metricmind...right?


Let's just say the battery was built by us using surplus parts


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## Kelmark (Oct 26, 2009)

major said:


> Here is a chart. Hopefully it gets attached to post. I've had trouble doing this before.
> 
> This is a discharge this we ran prior to sticking it in the cart. Our data computer wasn't working, so we had to "hand" read values and stick them into excel. But it gives the general capability at 2C. Temperature rise was only about 10F.
> 
> ...


I am considering using Kokam SLPB 75106100 on my EV so I am anxious to get some real world feedback on them as far as voltage sag and their ability to stay balanced. They are priced high so I would expect to see solid performance.


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## major (Apr 4, 2008)

Kelmark said:


> I am considering using Kokam SLPB 75106100 on my EV so I am anxious to get some real world feedback on them as far as voltage sag and their ability to stay balanced. They are priced high so I would expect to see solid performance.


Hi Kel, 

See the graph in post #12. That is about as real world as it gets. Hope to have some more data for ya soon,

Regards,

major


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## Kelmark (Oct 26, 2009)

major said:


> Hi Kel,
> 
> See the graph in post #12. That is about as real world as it gets. Hope to have some more data for ya soon,
> 
> ...


Major, 

What type of Kokam batts are you using? The high power or High density? The ones I am looking at are the high density rated at 2c continues and 5c max. (not sure how long max can be maintained without damage?) Just wondering if looking at your chart I am comparing apples with apples or not.

Thanks


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## major (Apr 4, 2008)

Kelmark said:


> Major,
> 
> What type of Kokam batts are you useing? The high power or High density? The ones I am looking at are the high density rated at 2c continues and 5c max. (not sure how long max can be maitained without damage?) Just wondering if looking at your chart I am comparing apples with apples or not.
> 
> Thanks


Not sure. I'll get the part #. They were 40 Ahr cells, so a 2C discharge.

major


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## RoughRider (Aug 14, 2008)

forget about KOKAM...

take the A123 20Ah cells...they are MUCH better...and LESS expensive...


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## Kelmark (Oct 26, 2009)

RoughRider said:


> forget about KOKAM...
> 
> take the A123 20Ah cells...they are MUCH better...and LESS expensive...


Can you give some details on why you feel they are better and how or where to buy them. I am open to alternatives but the pack has to be as light as possible.


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## CroDriver (Jan 8, 2009)

Kelmark said:


> Can you give some details on why you feel they are better and how or where to buy them. I am open to alternatives but the pack has to be as light as possible.


Hi Kelmark. 

I'm building two cars with these cells. I have tested many Lithium cells and this flat 20Ah A123 cells are the best, by far. I'm purchasing them in large quantaties (2000 cells) so I have a good price.










I have also pictures and videos of other tests, some even with IR camera videos and very heavy loads. They can give over 20C (400 Amp) continuous without getting hot and staying at over 2,3V. They have a claimed life of 10.000 cycles 

If you need more info, send a p.m. 

Regards,

Mate


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## RoughRider (Aug 14, 2008)

CroDriver said:


> Hi Kelmark.
> 
> I'm building two cars with these cells. I have tested many Lithium cells and this flat 20Ah A123 cells are the best, by far. I'm purchasing them in large quantaties (2000 cells) so I have a good price.
> 
> ...


hey CroDriver...you are a real serious man...2000 cells...not bad


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## Matthijs (Jun 19, 2009)

http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=15093&start=105


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