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Old Oct 02, 2002, 08:55 PM
Live to ride... and fly!
Tres Wright's Avatar
Forney, TX
Joined Mar 2002
15,165 Posts
FMA Kokams are here!!

I ordered some Kokam lithium ion polymer batteries from FMA a month ago or so, but they quickly ran out. Well today I received a surprise package that contained my 4 1020 mah Kokam cells!! Woohoo! I immediately popped 2 on the scale and they are dead on 1.5 ounces as advertised. As you can see in the pic, they come as bare cells. They look strangely like foil covered chocolates I'm greatly looking forward to trying these out on ALL my QC powered planes, especially the M100 equipped planes. I'm also particularly curious to see what the 1/2 ounce weight savings over QCs does for the vertical on my Wing-E and Mini IFO!

For more info, jump to this thread:

Kokam Lithium Polymer Batteries!
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Old Oct 02, 2002, 09:58 PM
Senior Member
Des Moines Municipal, Iowa, United States
Joined May 2002
401 Posts
Great news! I gotta get an order in.
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Old Oct 02, 2002, 10:32 PM
I am to the limit!
Jeff Costantino's Avatar
Coral Springs, FL
Joined Sep 2002
138 Posts
What is the maximum discharge? Still 2C like the Sony Energytec cells?

Jeff
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Old Oct 02, 2002, 10:34 PM
MKH
Registered User
Ohio
Joined Mar 2000
2,597 Posts
I think you're gonna like these cells, Tres. You should lose 1/2 an ounce, and gain a few rpm. Now that FMA's prices are firmed up, and very reasonable, your beloved qualcomms may soon go the way of the Dodo.

Looking forward to your flight reports and comparisons. I never personally owned qc's, so my only lithium time is with polymers.

Marcus
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Old Oct 02, 2002, 10:56 PM
Live to ride... and fly!
Tres Wright's Avatar
Forney, TX
Joined Mar 2002
15,165 Posts
Jeff-

==What is the maximum discharge? Still 2C like the Sony Energytec cells? ==

According to testing that you can read about in that other thread, the "safe" discharge is 4C, but people have been pushing 5C. This is also impacted by the size of the cells. Kokams are performing at a completely different level than any other li-ons out there.

Marcus-

I've hit the 3 amp limit on the QCs more times than I care to think about! I'm anxious to try the Kokams on some of those old tests. The weight savings and increased capacity over the QCs has me excited as well! I've got a pack charging right now, I think the Mini IFO will be the test subject
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Old Oct 02, 2002, 11:01 PM
I am to the limit!
Jeff Costantino's Avatar
Coral Springs, FL
Joined Sep 2002
138 Posts
WOW!!! That's a pretty good discharge rate! 5C is plenty for most park flyers but you could always make a series-parallel pack for 7.2v and 10C amp draw..

Jeff
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Old Oct 02, 2002, 11:12 PM
MKH
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Ohio
Joined Mar 2000
2,597 Posts
I can't back this up with any data, but I believe the 4C to 5C max discharge rates for these polymer cells is for short bursts only. I pull up to 4 amps on my 950's, but only for very short bursts, and I've had no degradation in these packs since new.
Marcus
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Old Oct 03, 2002, 12:05 AM
Senior Member
Des Moines Municipal, Iowa, United States
Joined May 2002
401 Posts
I have some 2 cell and 3 cell 950 Li-ions (not bad, but expensive) as well as Qualcomms (not bad and cheap! but a few shutdowns in my experiences as well). I just placed my order for some Kokam 560s, 1020s, and 3270s - cant wait to see how these Kokams perform, the weight sure looks good! I feel pretty confident that I have disassembled my last cell phone pack.

I am sure I will destroy or noticably degrade a pack or two during my brushless testing. I will let ya know how it works out.
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Old Oct 03, 2002, 12:37 AM
BEC
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Auburn, Washington USA
Joined Jan 2001
12,937 Posts
I sure wish the 3270s would fit in a Switchback! A three cell pack of those, on a miniAC 1215/20 geared appropriately for about a 10X7 SF prop....... would be mah -ve -lous......
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Old Oct 03, 2002, 01:42 AM
Dimension Engineering
Akron, Ohio
Joined Jan 2002
1,705 Posts
Why wouldn't they? Just do a bit of re-engineering to put the cells in the wing instead of the fuse? Real planes store their fuel in the wings all the time, and what stopped people from doing it in the past was mostly the round nature of the cells...
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Old Oct 03, 2002, 06:35 AM
(aka Cliff Lawson)
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United Kingdom, Essex
Joined Oct 2001
1,897 Posts
Hi,

I was just wondering - what do people use to charge the Kokam cells? Are you just using the Qualcomm charger? Would any mobile phone charger work OK?

Cliff
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Old Oct 03, 2002, 08:53 AM
Former bpp dude
Joined Oct 2001
1,025 Posts
Hello All, I am stocking the Kokam 1020's also & have many in stock. The 1020's are great for speed 280 & below applications requiring 4amps & below in current. You can push them harder into the 5+amp range but you MUST use throttle management. You can run them in parallel to double, triple, or quadruple their current capacity to handle motors from speed 300's- to hot speed 400 brushless setups. I have been running four 2 cell packs in parallel with a plane that will pull 26amps static. Very hard on the cells but its a blast to fly a plane with a 4,080mah battery pack that pulls that much current(no more 5 minute flights!). Please check out www.b-p-p.com for more info.

As for charging, the qualcomm charger will charge any of the cells from the 880's on up but the qualcomm charger usually stops at 8.2v so the charge on a two cell pack is a bit low. I have found a 5 dollar charger from RadioShack that will charge a 2 cell pack to its full capacity in aprrox 2 hours. I will post back with its catalog number if you guys would like to try to pick some up at your local RS.

I also will be stocking many different chargers as well as my own design within the next few weeks. For right now, the only way to charge 3 cell packs is via a $$$orbit or shulze, ginzel$$$$ chargers or through the Li-poly charger that wildrc & hobbylobby carry. Thanks

-Troy

Bishop Power Products

www.b-p-p.com (still under some construction)
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Last edited by ls77; Oct 03, 2002 at 09:14 AM.
Old Oct 03, 2002, 08:59 AM
Registered User
Iron Mountain,MI
Joined May 2002
2,272 Posts
Link ???????
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Old Oct 03, 2002, 09:02 AM
Registered User
Iron Mountain,MI
Joined May 2002
2,272 Posts
http://www.b-p-p.com/products.htm I see - gotta change the link to include the dash.
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Old Oct 03, 2002, 09:13 AM
Former bpp dude
Joined Oct 2001
1,025 Posts
sorry guys, I should allow at least 10 minutes after I wake up before I post

-Troy
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