I am putting up for sale my blackshadow terminator U3 for sale. Need some funds for a few other projects. Regretfully I need to let this light go - it really packs a punch too! 3500 lumens on high!
Yeah, anyway! IIRC all we heard about the first one was disappointment and apparent regret for getting it and now this will be your 4th one? You got some ‘splainin’ to do, Lucy! :bigsmile:
I’m hoping to get one that lives up to it’s claimed lumen output. But I don’t think it will happen.
The driver is pulling 8 amps at 4.0V in. The best it can do is deliver 2 amps to each LED, but due to driver losses of 10% that would be 1.8 amps per LED. An XML U3 and 1800 mA puts out 712 lumens (according to Match’s numbers, 14% higher than a T6). That gives 2850 emitter lumens… allow for 75% optical efficiency and you get 2137 OTF lumens. My three lights put out 2050 lumens (T6), 2150 lumens (supposed U3, but most likely isn’t) and 2330 lumens (known U3).
Working the numbers based on watts in to the driver (instead of amps), gives pretty much the same numbers. There is no way in the known universe these things can put out 3500 lumens.
But still, they are very nice lights and I want to equip my army of liquid metal cyborgs with them so we can take over the world in style.
Ceiling bounce tests cannot be trusted, particularly with high power lights and lights with intense hotspots.
To get 3500 lumens OTF you, each LED needs to be dumping 3500/4*1.25 lumens -> 1100 lumens. A top end U3 might hit that at 4.5 amps per LED. 4.5 * 4 * 1.1 means a tailcap current of 20 amps… ain’t gonna happen. You need a better bathroom… or an accurate integrating sphere. Oh, and at over 72 watts in, the Terminator would revert back to liquid metal in no time…
Yes it is. I still don’t know how TP gets such low readings from his BST’s. I know he has full faith in his box o’ many mysteries but I can’t help but question it. My IS doesn’t show 3500 lumens for either of mine but I do get 3200 on my U3 model. My IS is calibrated and both Match’s and mine get the same results in testing the same exact light he made and same models from various manufacturers. I trust my numbers.
for whatever its worth i tested the tn30 xml2 on high and got 312 lux doing the same bounce test (rated at 3300 lumens)
i purposely made sure to setup the light meter on the other side of the room so as not to pick up the hotspot and get a false reading on either test
i guess there really is no 100% accurate way to compare “apples to oranges” in this case and i should just build a sphere … i will do some reading up on one this evening.
Work the numbers backwards from OTF lumens to the current/power required to give those lumens and see how those jive with the real world… you can assume 75% optical efficiency and 90% driver efficiency.
shipping tomorrow 