A photo of my daughter, printed on Kodak Metallic Paper at 24x36. These pics taken moments ago with my i8 locked at 4352K and with 2 lights at approx the same output. Bet it doesn’t take you much of a guess as to which one I’ll be throwing the emitters away…
Luck of the draw perhaps. But yeah, they didn’t stay in my E07 very long at all. The nice tint, on the left, is the E07… with LH351D 5000K W6 emitters.
Beam profile is nice, Turbo tint is nice, but at lower output level just a fail on an FET driver. Maybe I’ll try em on Neven’s regulated driver and see how that goes, probably the same though…
I didn’t compare heat or amps or runtime, but when I compared tint of SST-20 4000K 95CRI to an XP-L HI 5A/5D, I found the XP-L HI made a much nicer-looking beam despite the lower CRI. SST-20 looked fine at high levels, but I don’t use high levels very much.
With an amc7135 chip like the D4 uses, the bottom half of the ramp stays in regulation longer with lower-Vf emitters. Basically, it stays in regulation as long as the battery voltage is higher than the emitter voltage. Then on a low battery, output falls much like it would with a direct-drive circuit. It’s a lot like a buck driver, except it burns off extra voltage instead of converting that to current.
Heat can definitely be a problem when burning off extra voltage like this, but the 7135 chips have their own thermal regulation built in. It typically works well as long as the voltage is within spec. It doesn’t work at 5V and above though, and the chips tend to die when used that way.
I stand corrected, I understand what Blue was saying now. But to poke at this a bit further, is the Vf at 0.35A really above 3V, and in the D4 now we are talking less than 0.1A per diode. I’m still thinking you are not staying in regulation on a rechargeable li-ion battery in a D4 before the voltage is so low it no longer safe to be operating. Guess it is time to investigate the Vf for an XPL-HI led.
Thanks, looks like roughly 2.74V of diode voltage for more than 0.1A of current (as the 0.35A gets split to 4 LEDs), and supposedly 0.12V across the 7135, so the light will regulate down to 3V easily at the full 0.35A going through 4 diodes. BlueSwordM is correct, but I’m guessing most of us are not planning on using batteries at less than 3V consistently.
Does it take a week to ship? I ordered a D4 last friday, and 7 days later the status is still “processing”. It is in stock, so is it normal or should I start to worry?
