[turboBB]

In my quest to find the best rechargeable cells for my SF lights, I recently picked up some AW LiFePO4's rated at 500mAh capacity and then put it to the test against Tenergy's LiFePO4 offering (rated at 750 mAh).

In anticipation of using these in a M3LT, the cells were tested in a Lumapower VX Ultra which has been stated to draw approx. 2.1A on high.

Starting/Ending V (IMR thrown in for comparative analysis):
AW - 3.78/2.95
Tenergy - 3.75/2.94
IMR - 4.18/2.73

I've found that the LiFePO4's come off the charger at approx. 3.8v but will settle down to about 3.5ish after a few hours or so. I usually run the cells down a little further to about 3.3v before shoving them in SF lights just to be safe but since the VX Ult was designed for RCR's I simply conducted the tests shortly after the batteries came off the charger.

Here is the result:

X axis = Time (Min) / Y axis = Relative light output

Test conducted w/fan on. Surface temp of light @ the head was 81.5F at start and never got more than 86.5F throughout the tests. EDIT: For the LiFePO4's, I actually shut off the light @ approx. 53 min as I didn't want to over discharge the bat's.

Given the oft exaggerated stated capacities by certain brands and how highly vaunted AW's cells are, I was actually expecting the AW's to do better but it seems it got bested by the Tenergy (even if slightly). I plan on running the tests again as it seems there is some anomaly w/the level that the AW's started off at before it took a nose dive.

Cheers,
Tim


Dave,

Yeah, these are being overcharged a bit so I usually try to monitor charging and pull them when the LED goes from Red to Red/Green (Green = Fully charged).

How do you like the DX cells and do you have any other LiFePO4's to compare them to? I notice the size is 17340, can they fit in stock SF lights (specifically E2DL or U2A since those seem to be tight fit vs. say a G2Z).

Here are two more charts, again the Tenergy bests the AW's in each.

Zebralight SC30 - 1 cell (anomaly uptick for IMR is due to me finding sweet spot for light meter to capture max lux):


Surefire E2DL - 2 cells (anomaly uptick at beginning of Tenergy run is due to me finding sweet spot for light meter to capture max lux):


Unless these just so happen to be a low performing AW's, the Tenergy cells have definitely held their own.

EDIT: (Unscientific but here goes...) Using the E2DL as the baseline and taking into consideration that the runtime to < 50% as quoted by SF for High is 1.9hrs (114min) and on primaries (usually @ 1550mAh), then the 39 min to < 50% output for the AW's is approx. 34% of which would yield 527 mAh and is pretty accurate for the rating. The Tenergy would be 43 min to < 50% output is 37.7% less than primaries and would yield about 584 mAh. Overrated they are but at least they currently are the best bang for buck and run time @ $3.29 from BtyJunc vs. $6.49 per pop for the AW's from Lighthound (where I made each respective purchase).

Cheers,
Tim