Kokam America

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EbikeMaui   1 kW

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Kokam America

Post by EbikeMaui » Apr 02 2007 3:09pm

Joon Kim (formerly from EgalePicher) and JJ Hong (the Kokam CEO and Kokam battery developer) are now the co owners of Kokam America.Production is the USA is being set up now! Today many ebike companies ARE testing KOKAM ebike packs such as this.In most cases a BMS is NOT used or needed using the larger cells.With this 7 cell pack 800 to 1000 cycles are available at 1 C discharge rates to 80% discharge without a BMS.You can take these cells down to 2.2 volts without hurting them.
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Ebike packs being tested
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Last edited by EbikeMaui on Apr 02 2007 3:23pm, edited 1 time in total.
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Ypedal   100 GW

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Post by Ypedal » Apr 02 2007 3:11pm

Yeah.. well i hope they do better than their Canadian branch.... Cantech sucks balls .. horrible service. :evil:
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EbikeMaui   1 kW

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Post by EbikeMaui » Apr 02 2007 3:57pm

Ypedal wrote:Yeah.. well i hope they do better than their Canadian branch.... Cantech sucks balls .. horrible service. :evil:
KoKam batteries started the RC Li-Po Revolution! the same way Aveox started the RC BLDC motor Revolution in 93'
I fail to see your Canadian connection.
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Now at your RC dealers
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xyster   1 GW

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Post by xyster » Apr 02 2007 4:53pm

KoKam batteries started the RC Li-Po Revolution!
Kokam couldn't have hired a more objective and thoughtful salesperson. You are getting paid for this, right?
Ebike: 5304/20", 72V 35A controller, 33AH 80V 20s15p (18650 sized cells) DIY lithium-ion pack
http://endless-sphere.com/forums/viewto ... 47&start=0
Scooter: '06 Stealth s1000, 48V 30A, 4x10ah SLA
http://endless-sphere.com/forums/viewtopic.php?t=148
Ebike: '06 Currie Mongoose, 32V 35A, 32V 22AH hybrid SLA/Li-ion pack
http://endless-sphere.com/forums/viewtopic.php?t=1010

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EbikeMaui   1 kW

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Post by EbikeMaui » Apr 02 2007 7:11pm

xyster wrote:
KoKam batteries started the RC Li-Po Revolution!
Kokam couldn't have hired a more objective and thoughtful salesperson. You are getting paid for this, right?
Developing a future product of quality will take more time to test every component.The last being batteries that are developing rather rapidly.Right now there is no other li-po manufactures that offer long cyclelife and deliver! A must for any New complete ebike product to make it in this fragil market.
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Lowell   1 MW

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Post by Lowell » Apr 03 2007 3:08am

xyster wrote:
KoKam batteries started the RC Li-Po Revolution!
Kokam couldn't have hired a more objective and thoughtful salesperson. You are getting paid for this, right?
What exactly are the rules here for advertising?

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fechter   100 GW

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Post by fechter » Apr 03 2007 8:51am

In order to be considered advertising, I would assume it would have to be an actual product that you could actually buy. Otherwise, there's no money to be made.
"One test is worth a thousand opinions"

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patrick_mahoney   100 W

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Post by patrick_mahoney » Apr 03 2007 10:17am

With this 7 cell pack 800 to 1000 cycles are available at 1 C discharge rates to 80% discharge without a BMS. You can take these cells down to 2.2 volts without hurting them.
Definitely you can get long cycle time reliability out of both lithium ion and lithium polymer batteries by keeping the discharge rates low - but for a 20A discharge, this would be a 20Ah battery. This is what is planned for e-bikes?

Also, how do you keep a 7 cell pack in balance without a BMS? I can believe 1000 cycle data, but I have trouble accepting the idea that you can do get 1000 80% DOD cycles from a 7 cell pack without balancing. Lithium polymer batteries do not like overcharging (as opposed to SLA's and NiMH which are more tolerant), so a balancer is required.

How is the cold temperature (~0C) operation? Lithium polymers have never done well at or below freezing.

Lastly, cycle times are not my personal biggest concern with the use of lithium-based batteries - it's the shelf life that I worry about. How long do these new Kokam's last in the face of oxidation issues? How long is the shelf life when the pack is stored in a garage that spends most of it's summer about 25C? I have a Kokam pack from 2 years ago that has about 75 cycles on it that is already showing signs of shelf life problems. Few are going to want to buy an expensive lithium polymer e-bike battery that starts showing signs of substantially reduced capacity after a couple of years.
KoKam batteries started the RC Li-Po Revolution! the same way Aveox started the RC BLDC motor Revolution in 93'
This statement sounded like hyperbole to me when I first read it ... but I was on RC groups way back when JJ Hong was posting and I would have to agree that Kokam basically did start - along with Thunder Power - the RC lithium polymer airplane conversion. My first lithium polymer pack was a Thunder Power (the CEO of Thunder Power used to post at RC Groups as I recall as well). I remember when I bought it no one that I knew used lithium polymer batteries. Kokam was one of the key players in RC lipoly conversions - if not the very first.
In order to be considered advertising, I would assume it would have to be an actual product that you could actually buy. Otherwise, there's no money to be made.
Good point. :)
Last edited by patrick_mahoney on Apr 03 2007 3:58pm, edited 1 time in total.
9Continent 2807/700C, 36V 25A Infineon controller (w/ regen), 48V 15Ah "Ping" LiFePo battery

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Toorbough ULL-Zeveigh   10 MW

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Post by Toorbough ULL-Zeveigh » Apr 03 2007 2:38pm

I didn't think the copyright office would grant a copyright on something pieced together from copyrighted material.

Or is it alright cuz it contains precisely 49% recycled materials?

:!: wait a sec...


Image






The copyright won't hold up anyway since the copyright symbol is an ampersand. :lol:
Kick down the barricades Listen what the kids say.
From time to time people change their minds But the Frock is here to stay.
I've seen it all from the bottom to the top Everywhere I go the kids wanna Frock.
Around the world or around the block Everywhere I go the kids wanna Frock.

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EbikeMaui   1 kW

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Post by EbikeMaui » Apr 10 2007 4:44am

Toorbough ULL-Zeveigh wrote:I didn't think the copyright office would grant a copyright on something pieced together from copyrighted material.

Or is it alright cuz it contains precisely 49% recycled materials?

:!: wait a sec...


Image






The copyright won't hold up anyway since the copyright symbol is an ampersand. :lol:
These are illistrated improvments over pryor art work
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Toorbough ULL-Zeveigh   10 MW

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Post by Toorbough ULL-Zeveigh » Apr 10 2007 7:39am

Didn't you steal someone elses artwork with the fork, seat, fenders, lights, mirrors & wheels cuz it sure looks different from your original line art additions. Just cuz you removed the name off the shock doesn't give you copyright over it.
Kick down the barricades Listen what the kids say.
From time to time people change their minds But the Frock is here to stay.
I've seen it all from the bottom to the top Everywhere I go the kids wanna Frock.
Around the world or around the block Everywhere I go the kids wanna Frock.

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TylerDurden   100 GW

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Post by TylerDurden » Apr 10 2007 8:18am

It ain't so much advertising as it is wishful thinking.

RD's been lickin-up Kokam for years now, and they haven't backed his wanabee enterprise. What does that say?

You never can tell though... if the local shops want to carry Optibike, that might be enough validation of interest to get some VC involved. (cheaper, faster better, blah, blah)

Still a niche, tho. You'd have to demonstrate a wider market potential... like the Segway-tour gigs.


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EbikeMaui   1 kW

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Post by EbikeMaui » Apr 10 2007 4:49pm

TylerDurden wrote:It ain't so much advertising as it is wishful thinking.

RD's been lickin-up Kokam for years now, and they haven't backed his wanabee enterprise. What does that say?




.
THERE IS NO VIABLE EBIKE MARKET IN THE US. The Kokam cars may be the first electric vehicles to take advantage of Kokams Technology bucause ebikers can not afford KOKAMS for 1000 cycles.
http://tinyurl.com/2s7lqx
Last edited by EbikeMaui on Apr 11 2007 4:47am, edited 1 time in total.
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Lowell   1 MW

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Post by Lowell » Apr 10 2007 4:57pm

EbikeMaui wrote:
TylerDurden wrote:It ain't so much advertising as it is wishful thinking.

RD's been lickin-up Kokam for years now, and they haven't backed his wanabee enterprise. What does that say?




.
THERE IS NO VIABLE EBIKE MARKET IN THE US
Who is buying all the ebike products? For example, a few months ago Ebikes.ca was overflowing with inventory, and the last time I was at the shop, the shelves were looking noticeably light.

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EbikeMaui   1 kW

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Post by EbikeMaui » Apr 10 2007 9:43pm

Lowell wrote:
EbikeMaui wrote:
TylerDurden wrote:It ain't so much advertising as it is wishful thinking.

RD's been lickin-up Kokam for years now, and they haven't backed his wanabee enterprise. What does that say?




.
THERE IS NO VIABLE EBIKE MARKET IN THE US
Who is buying all the ebike products? For example, a few months ago Ebikes.ca was overflowing with inventory, and the last time I was at the shop, the shelves were looking noticeably light.
There is also a ass for every hubmotor ebike.But there are no other reasonable and available choices.
Happy Amping....
Aloha! RD
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Kraeuterbutter   100 W

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Post by Kraeuterbutter » Jun 14 2007 6:57am

for Kokam and RC-world..

the Kokams are maybe not the most powerfull cells (voltage under load),
and not the cells with most energy/weight,

but from my experiences (and i see this in many forums as well) the most reliable cells..

we empty our batts in rc-world usually in 5 - 8min, so lot of stress for batts
and recharge them often with 2C (or even more)
(so maybe more stress than in a electric bike-situation)

i can not speak for the bigger cells/packs you wana use in an ebike..

but one example:
i was comparing in same heli-application
Thunderpower vs. Kokam
thunderpower was lighter, giving 20% more capacity at same weight

my first Gen2-pack from Thunderpower failed after ~70cycles
the next was Gen2.5, i was told by Charly from Thunderpower that this would hold much longer -> ~70cycles
then the Prolites and Prolites plus came to the market..
i have not much cycles with the Prolite plus => 2years, stored at 20°C with ~50% charge inside
--> have now maybe 30-40cycles on them and the punsh has gone :(

my Kokam3200 is a little bit heavier, having not as good energy-densitiy like the thunderpower...
BUT: they are now over 200cycles old and still work... (same punsh, about 80% of original capacity)

i had meanwhile about 10 different lipo-brands.. the most reliable are the kokams (for me the 3200mah-cells) so far

looking into the german RC-forums: there are barrley cells with are over two years old and work still fine...
there is a good chance that if you find such a battery, its a Kokam..

hope you dont see this as a advertisement, its just the experience i and my friends made over the last 3 years...
and it is to say: we use smaller cells (350mah up to 5000mah) and stress them maybe a little more (up to 20c continouse discharge, charging with 2-3C (Fepo4 A123 with up to 10C in 5min *lol*)

for cycle-test under heavier loads (not only this 1c discharge-rates you see everywere):
here a - i think - very well done test of different cells at higher loads, good documented how it was done:

the new Kokam4000 cell: http://www.slowflyer.ch/downloads/tn07004.pdf
the Kokam4800cell, charged with 3C: http://www.slowflyer.ch/downloads/tn06007.pdf
Polyquest: http://www.slowflyer.ch/downloads/tn06001v2.pdf
Flightpower: http://www.slowflyer.ch/downloads/tn06002.pdf
Flightpower new formulation: http://www.slowflyer.ch/downloads/tn060051.pdf
http://www.slowflyer.ch/downloads/evo1500.pdf

you can find the links to the tests here:
http://www.slowflyer.ch/000000972c0e2a4 ... /index.php

the site is German (well, swiss), but the tests are made (i think most of them) in English language..

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EbikeMaui   1 kW

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Post by EbikeMaui » Jun 14 2007 3:15pm

Kraeuterbutter wrote:for Kokam and RC-world..

the Kokams are maybe not the most powerfull cells (voltage under load),
and not the cells with most energy/weight,

but from my experiences (and i see this in many forums as well) the most reliable cells..

we empty our batts in rc-world usually in 5 - 8min, so lot of stress for batts
and recharge them often with 2C (or even more)
(so maybe more stress than in a electric bike-situation)

i can not speak for the bigger cells/packs you wana use in an ebike..

but one example:
i was comparing in same heli-application
Thunderpower vs. Kokam
thunderpower was lighter, giving 20% more capacity at same weight

my first Gen2-pack from Thunderpower failed after ~70cycles
the next was Gen2.5, i was told by Charly from Thunderpower that this would hold much longer -> ~70cycles
then the Prolites and Prolites plus came to the market..
i have not much cycles with the Prolite plus => 2years, stored at 20°C with ~50% charge inside
--> have now maybe 30-40cycles on them and the punsh has gone :(

my Kokam3200 is a little bit heavier, having not as good energy-densitiy like the thunderpower...
BUT: they are now over 200cycles old and still work... (same punsh, about 80% of original capacity)

i had meanwhile about 10 different lipo-brands.. the most reliable are the kokams (for me the 3200mah-cells) so far

looking into the german RC-forums: there are barrley cells with are over two years old and work still fine...
there is a good chance that if you find such a battery, its a Kokam..

hope you dont see this as a advertisement, its just the experience i and my friends made over the last 3 years...
and it is to say: we use smaller cells (350mah up to 5000mah) and stress them maybe a little more (up to 20c continouse discharge, charging with 2-3C (Fepo4 A123 with up to 10C in 5min *lol*)

for cycle-test under heavier loads (not only this 1c discharge-rates you see everywere):
here a - i think - very well done test of different cells at higher loads, good documented how it was done:

the new Kokam4000 cell: http://www.slowflyer.ch/downloads/tn07004.pdf
the Kokam4800cell, charged with 3C: http://www.slowflyer.ch/downloads/tn06007.pdf
Polyquest: http://www.slowflyer.ch/downloads/tn06001v2.pdf
Flightpower: http://www.slowflyer.ch/downloads/tn06002.pdf
Flightpower new formulation: http://www.slowflyer.ch/downloads/tn060051.pdf
http://www.slowflyer.ch/downloads/evo1500.pdf

you can find the links to the tests here:
http://www.slowflyer.ch/000000972c0e2a4 ... /index.php

the site is German (well, swiss), but the tests are made (i think most of them) in English language..
Thanks for the important data :)
Efficiency and longevity Rules!
http://video.google.com/videosearch?q=ecyclemaui

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