I was testing some new xtar 3100’s against my old standbys of Tenergy protected 2600’s.What I found seems to go against what I was expecting.In a direct drive on high light (Romisen T602 from Shiningbeam) I am getting a tailcap draw of 3.7 amps with a freshly charged Tenergy, but only 3.44 amps with the xtar 3100’s at the same voltage?I would have expected the twice as expensive battery to at least equal the tailcap draw of the supposed lesser battery, but to be lower?This lower draw would seem to indicate (using olm’s law) that the xtar’s have a higher internal resistance….isn’t that an indication of a lesser battery?Am I missing something here?For 31$ a pair I hope I am!-Rick
Tenergy 2600's are actually really good batteries. I've always been happy with mine.
HKJ's testing show that they're better at handling load than Pana 2900's, so maybe the same goes for the 3100's.
I've got some Tenergy 2600's (protected) and Keeppower Panasonic 3100's (Keeppower). I could test in my direct drive UltraFire 3 mode P60 drop-in for comparison, but I'd have to charge them up so they are equal. I've always had good performance from my Tenergys.
-Garry
Many batteries seem to have less capacity at higher draw. So as a guess, one of the ways capacity might be reliably increased is to restrict the draw rate.
It also might vary from light to light (or driver) - in one of my lights a UF 4000 outperforms a new IMR.
OK, my test results are in. I ran an Manafont Ultrafire 3 mode P60 drop-in (direct drive on high) in a Fake L2 host (copper foil wrapped) on high with 3 different batteries all fresh off the charger and all protected.
Tenergy 2600mAh @4.19v:
Hi - 4.40A
Keeppower (Panasonic) 3100mAh @ 4.21v:
Hi - 4.80A
Trustfire Flame 2400mAh @ 4.22v:
Hi - 4.85A
I'm very surprised by the TF flame result! Didn't see that coming! I don't have any other 18650's to test to compare.
I didn't think the Romisen T602 was a direct-drive light?
-Garry
Thanks for looking into this Garry.I am very suprised by the TF flames at 4.85 amps! 
Thats a bit scarry!I may be wrong about the T601 &T602 being direct drive…thought I had heard it mentioned here.Still don’t understand why my 16$ batterys are outperformed in current draw by an 8$ battery though?And how the hell you are getting 4.85 amps from a 5$ battery?This is giving me a headache….I’ll think I’ll just keep buying Tenergy 2600 and not think about it anymore!-Rick
Yeah, I thought about posting the question in a new thread (although it's nearly the same question as yours - Why is a TF Flame pulling more current than a Panasonic?). Bought my TF Flames from KD and I believe they are legit. They are definitely protected too. I don't have any way to measure capacity of 18650's though.
That Romisen sure sounds like it's direct drive since you're getting readings over 3A and they vary between cells, but I wonder why you're not getting higher readings, closer to 4A? Could it be your meter or leads? Or does that light have more resistance in contacts than my Ultrafire drop-in setup? Hmm. . .
-Garry
Are the Tenergy protected 2600’s using the Sanyo UR186650FM batteries inside? If they are Sanyo cells, the Sanyo’s don’t seem to drop off as fast at 3-5A.
I've never heard anyone say they use Sanyo cells. Anyone know?
-Garry
No, they don’t use Sanyo cells. Tenergy manufactures their own (but very decent) Li-Ion cells.