DIY Electric Car Forums banner

1 - 20 of 26 Posts

·
Registered
Joined
·
1,956 Posts
Discussion Starter #1

·
Registered
Joined
·
1,956 Posts
Discussion Starter #3

·
Registered
Joined
·
370 Posts
So the K2's are roughly equivalent to A123? Interesting; because you can actually buy 72ah 3.2v packs of these from at least one EV parts distributor I've seen. They come at a pretty steep cost though, but if they're really that good they should work well for a no compromises performance EV build if you've got the scratch to spend.
 

·
Registered
Joined
·
363 Posts
When you buy K2 in numbers and test them you will not find the same level of QC and consistency as you will with A123's. When your going to make a pack from that many cells this is important.

Steve
 

·
Registered
Joined
·
1,956 Posts
Discussion Starter #7
Thanks, has anyone done this? Where can I find the link? :confused:

When you buy K2 in numbers and test them you will not find the same level of QC and consistency as you will with A123's. When your going to make a pack from that many cells this is important.

Steve
 

·
Registered
Joined
·
1,956 Posts
Discussion Starter #8
K2 Energy has their own store, what EV parts distributor is selling them?

So the K2's are roughly equivalent to A123? Interesting; because you can actually buy 72ah 3.2v packs of these from at least one EV parts distributor I've seen. They come at a pretty steep cost though, but if they're really that good they should work well for a no compromises performance EV build if you've got the scratch to spend.
 

·
Registered
Joined
·
1,956 Posts
Discussion Starter #9
http://www.peakbattery.com/projects.html

Using our high performance 26650P cells with a 240V 300hp electric engine produces an astounding 1,000 lb/ft of torque!!! Leaving even most expensive supercars in the dust!

The Shelby brand, like K2 Energy Solutions, is synonymous with big power! When we teamed up with APT Automotive to build a custom battery system to power their Shelby Cobra EV, we knew the results would have to be impressive for such a legendary car but when we ran 3.2 second 0-60 time, we were all blown away. Imagine a classic like the Cobra flying by without a plume of exhaust fumes trailing behind. :confused:
 

·
Registered
Joined
·
2,494 Posts
man... I've always wanted to build an AC Cobra kit car.... in the past year, I've dreamed of building an electric one like this. drooling here....:p
 

·
Registered
Joined
·
370 Posts

·
Registered
Joined
·
1,956 Posts
Discussion Starter #12
Yes, it is sweet! ;)

I am interested in seeing this car and its battery pack, but I cannot find it anywhere? I will keep looking. :eek:

man... I've always wanted to build an AC Cobra kit car.... in the past year, I've dreamed of building an electric one like this. drooling here....:p
 

·
Registered
Joined
·
1,956 Posts
Discussion Starter #13
Very interesting:

"They are great building block to build a larger battery pack for those who want the power of the small cylindrical cells and the ease of the larger prismatics" :eek::eek::eek:

They have absolutely no details on their site, but there's one I've seen.
http://currentevtech.com/Lithium-Batteries/K2-Battery-Packs-c60/
They have absolutely no details on the packs though, other than saying they're similar in specification to a123 26650m1 cells, and they are pricey.
 

·
Registered
Joined
·
1,956 Posts
Discussion Starter #14

·
Registered
Joined
·
370 Posts
I'd assume it's just a pack with a bunch of 26650's in parallel. It's anyone's guess just how good they are, how well the cells are matched, etc. When I first saw them I searched around for any reviews or tests on those actual packs. I wasn't able to find anything myself. So it looks like someone with some bank will have to be a guinea pig before we know anything concrete.
 

·
Registered
Joined
·
17 Posts
Be very careful in any dealings with K2 (formerly Peak battery).

They have repeatedly understated the internal impedance of their previous 26650 cell offerings :mad: to say it nicely.

The prior model cells were sampled, tested using professional instrumentation, and returned room temp I/R numbers in excess of 20mohms @50% SOC. Many cells were tested, with similar results.

Their salesman skirted the I/R results when confronted with the numbers.

Now take on the other hand; LifeBatt :confused:

What you have here is a 3x overpriced Taiwanese assembled cell, that may contain some percentage of Phostech licensed powder ;) the remaining could be dandruff for all we know. The pricing, as we've surmised, has to do with the three year warranty offered (as long as you buy their BMS). The problem is that you'd be required to deal with a person named Don Harmon (douchebag extraordinaire) in the event of a problem, and that's where it will go south :( There is some history on this noted on this at another EV forum.

These are very good performing cells, delivering well within their stated impedance and capacity numbers. Isn't it funny? the product appears great, it's the company pitchman who is a trainwreck and can't keep his stories straight.


My advice? go with Headway cells from Victoria. They're relatively cheap, they appear to meet their cycle life numbers, and there is plenty of published data about various builds using them. The I/R numbers are somewhat high for EV use, so put a few more in parallel.
 

·
Registered
Joined
·
363 Posts
HEadway's will not work well in a drag car (in fact, I believe Crodriver tried them and found this out).
Unless you can get hold of A123's I would suggest looking into LiPo for light weight and extreme discharge rates..

Steve
 

·
Registered
Joined
·
1,956 Posts
Discussion Starter #18
You speak of LifeBatt, what is the highest C-rating batteries they produce? :confused:

Now the US batteries are not the batteries of the past sold in UK.

Be very careful in any dealings with K2 (formerly Peak battery).

They have repeatedly understated the internal impedance of their previous 26650 cell offerings :mad: to say it nicely.

The prior model cells were sampled, tested using professional instrumentation, and returned room temp I/R numbers in excess of 20mohms @50% SOC. Many cells were tested, with similar results.

Their salesman skirted the I/R results when confronted with the numbers.

Now take on the other hand; LifeBatt :confused:

What you have here is a 3x overpriced Taiwanese assembled cell, that may contain some percentage of Phostech licensed powder ;) the remaining could be dandruff for all we know. The pricing, as we've surmised, has to do with the three year warranty offered (as long as you buy their BMS). The problem is that you'd be required to deal with a person named Don Harmon (douchebag extraordinaire) in the event of a problem, and that's where it will go south :( There is some history on this noted on this at another EV forum.

These are very good performing cells, delivering well within their stated impedance and capacity numbers. Isn't it funny? the product appears great, it's the company pitchman who is a trainwreck and can't keep his stories straight.


My advice? go with Headway cells from Victoria. They're relatively cheap, they appear to meet their cycle life numbers, and there is plenty of published data about various builds using them. The I/R numbers are somewhat high for EV use, so put a few more in parallel.
 

·
Registered
Joined
·
39 Posts
We had the ability a while ago to utilize A123's in our packs but they just got so damn hard to deal with and decided to sell only to the big guys (or girls) that we went with [email protected] for a while and had no problems as long as we ordered from the same production run but we got a lot better price, great service and someone willing to align themselves with us and support us in the manufacturer Molicel. We utilize them exclusively now. I also have a post under Li-ion batteries about manufacturing packs. Jim @ ethos electric vehicles.com
 

·
Registered
Joined
·
1,956 Posts
Discussion Starter #20
What cell do you prefer from Molicel? I see none with decent AH, maybe I am missing something, i will review their site again. :confused:

http://www.molicel.com/ca/products_data.html

We had the ability a while ago to utilize A123's in our packs but they just got so damn hard to deal with and decided to sell only to the big guys (or girls) that we went with [email protected] for a while and had no problems as long as we ordered from the same production run but we got a lot better price, great service and someone willing to align themselves with us and support us in the manufacturer Molicel. We utilize them exclusively now. I also have a post under Li-ion batteries about manufacturing packs. Jim @ ethos electric vehicles.com
 
1 - 20 of 26 Posts
Top