Independent test on Kokam 4800

[Ashley Davis]

Just found this independent data on the Kokam 4800

http://www.slowflyer.ch/downloads/tn06007.pdf

The test shows no capacity loss (in fact the pack gained capacity) after 200 discharges at 12C, additionally the pack was charged at 3C (yes 3C !!) for every charge. Would have been nice if they had carried on to find out just how many cycles they could get out of it but at 200 it has GAINED capacity from the capacity measured at the first discharge.

Just thought I'd highlight this test as it is entirely independent and is proper testing to backup what I've been saying about the Kokam 4800 cells. Show me another cell that can take 3C charging for every charge and to have gained capacity at 200 cycles.

Before the FlightPower supporters jump on this here's the direct quote from the FlightPower site :

2.5C Charge 10C Discharge, cycle life expectation: 100 Cycles to 80% Capacity.
Fast charging at 2.5C is possible with the FlightPower EVO 20 packs in exchange for a reduction in cycle life. This is recommended "in case of need" and use of a balancer is advised.

And the quote above is NOT from an independent test, that's manufacturers figures if you like to believe in that sort of thing. One thing I also forgot to mention (so adding this by edit). Manufacturer figures are usually based on testing a single cell, not a pack. When you put cells into packs you get a reduction in cycle life. The Kokam test was on a pack, not a single cell.

[3dbasher]

kokams have always been the daddy just a shame there so heavy

[Ashley Davis]

They are heavier but matched to the correct motor in the T-Rex 600 it makes no odds (as demo'd by Ade today at DMHC).

[3dbasher]

surpose not just have to shift it about to get the CG right,
i have 2000mah 15c's in my 450 and are excellent but don't seem to have stupid climb rate as my fp 1800 because of the noticable weight difference

[Ashley Davis]

yeah, in smaller machines weight is much more critical to perfromance. In the 50 size class it's much less of an issue. 50g in a 450 is a much higher percentage in terms of power to weight than 200g in a 50.

[3dbasher]

very true

[Smoothound]

surpose not just have to shift it about to get the CG right,
i have 2000mah 15c's in my 450 and are excellent but don't seem to have stupid climb rate as my fp 1800 because of the noticable weight difference

Biggest problem is not so much the weight but that poxy over square shape. It's not too hard to nick back some of the 50g if you are clever and devious though...

Not that I want to be seen condoning the use of Kokam cells

[Ashley Davis]

It fits beautifully in the T-Rex 600, you just stand it up like most other packs and it fits between the side frames against the plastic support tray. It's neither too wide or too tall. It's exactly the same width as the Thunder Power 4500 cells (42mm).

[Ashley Davis]

ah, sorry, I see you were referring to the 2000mah 15C cells in a T-Rex 450 (doh). Yeah, it's a bit of an awkward shape to get in the canopy but it does go with a bit of shuffling

[Smoothound]

I have some older 2000mAh TP Prolites in my 4s Trex and they just fit on the SE frame upper mount but do rub on the canopy slightly. I keep putting strips of insulating tape on the pack rather than see a cell venting mid flight

Packs still perform reasonably well even after my abuse and the canopies rubbing up...I do like my 4s T-Rex

[Ashley Davis]

oh yeah, I loved those 2000mah prolites, they were great for 4S rex's.

[Thomas]

kokams have always been the daddy just a shame there so heavy

I had the privilege of not only seeing a Kokam in the flesh, I even held one, and ..... actually flew one

I was lead to believe the were heavy too but the 6s was about the same as my FP4900, though it was 500 ma smaller, couldn't say if it was a better LiPo than my FP's at the heli had a different motor to me - The Kokam doesn't seem to drop off as much as the FP's after the first couple of mins.

[Smoothound]

To be honest, I hate to say this as well, they are probably the 2 best packs I've had

[Thomas]

Blimey Phil, steady on, heard Ash tell Trev "FP's are not crap" today too - think I need to go and sit down.

[Smoothound]

Maybe it's time for me and Ash to have a beer, we're starting to find a small patch of common ground