26650 Batteries

texas_shooter · July 24, 2021, 2:06am

speedlever:

texas shooter:

I pulled up the Wurkkos TS70 review and output. 5500 lumens from a 6 volt Cree XHP70.2 is about 10 amps. This may help as the LED is driven past the Cree charts LED test / review - Cree XLamp XHP70.2 P2 40E (4000 K) - The second generation of extreme overcurrent and light flux capability?

Thanks. I’m not quite sure how to read the charts, but I saw this from the review you linked. Curious how that factors in…

“Overcurrent:
20 Amps lab power supply maxed out!
possible light flux maximum not reached at 20 A, 9,228 lm @ 7.29 V at 20 Amps
power at maximum 145.8 W
Sweet Spot at 15 A (8,379 lm @ 6.95 V)
power at sweet spot 104.3 W
efficiency at maximum 63.3 lm/W
efficiency in sweet spot 80.3 lm/W

I define the sweet spot as the position in the diagram which gives a good average between light flux, current and efficiency. In most cases it lays roughly 15 to 35 percent lower than maximum possible light flux.

The XHP70.2 is so powerful that my new power supply (20 A @ 30 V max.) limits the maximum possible current in this test. The maximum should be reached at 21 to 24 amps, at approx. 9,300 to 9,500 lumens. LED will be consuming 170 watts!”

Your light is claiming 5500 lumens really probable 4500-5000 lumens from other good quality lights of the same format “XHP70.2, 2-26650 batteries.” With a good power supple and ample heat sinking it could be brighter. Given internal battery resistance, voltage sag, electronics resistance, LED resistance, heat you hit a ceiling. Now it’s a good light and it’s weight will do well to keep that brightness up there. A smaller light would heat up quicker and that also reduces brightness quicker. Wurkkos TS70, Convoy L6, Sofirn TK70 and Thorfire S70 are the top tier.

Sillen · July 24, 2021, 3:36am

QFT! What about SP70?

texas_shooter · July 24, 2021, 4:07am

Haven’t played with that one. From reviews I thought it’s a larger reflector version of the TK70.

speedlever · July 24, 2021, 2:10pm

texas shooter:

The XHP70.2 is so powerful that my new power supply (20 A @ 30 V max.) limits the maximum possible current in this test. The maximum should be reached at 21 to 24 amps, at approx. 9,300 to 9,500 lumens. LED will be consuming 170 watts!”

Your light is claiming 5500 lumens really probable 4500-5000 lumens from other good quality lights of the same format “XHP70.2, 2-26650 batteries.” With a good power supple and ample heat sinking it could be brighter. Given internal battery resistance, voltage sag, electronics resistance, LED resistance, heat you hit a ceiling. Now it’s a good light and it’s weight will do well to keep that brightness up there. A smaller light would heat up quicker and that also reduces brightness quicker. Wurkkos TS70, Convoy L6, Sofirn TK70 and Thorfire S70 are the top tier.

What I was attempting to ask is about the fact he maxed out his 20A power supply vs using 10A batteries. Are you saying the ceiling limits the current draw? (I have the hots for an L7 now too) Hoo boy.