SolarForce T6 vs. U2 vs. U2 vs. V3

Hello all,

For a while now I’ve been confused. I have several SolarForce flashlights - L2T, 2xL2N, L2C and P1D. When I was getting them, I usually was ordering them with a newly released bulb. My first one was XML-T6, then XML-U2, then XML2-U2 and finally XPL-V3.
I’m using all of them with 18650 batteries.

Now, I can’t understand if I’m imagining it, but for me the oldest T6 seems brighter than the newer ones. Especially the first U2 looks kinda dim, the second U2 looks slightly better, and for the V3 maybe it’s the closest to the T6, still can’t decide which one is brighter. I don’t have a lightmeter or anything.

Can somebody explain if this is possible or I’m just imagining all this?

I was going to order the XPL-V6 with the last flashlight, but I saw it’s rated at 830 lumen and the V3 was rated higher, so I decided there’s no point.

Thanks for anyone’s time and sorry if the question is stupid, I’m not technically educated.

Two immediate things that come to mind are that the driver used in each drop-in may not be the same, & also the tint of the LED can make it appear more/less “bright”.

Some ways to investigate

Charge four identical batteries, check they each show the same voltage if they’re different types/ages
set the lights side by side and take a picture of the beam on a white wall and on a multicolored subject (knitting basket?)
— do they appear the same color temperature?
Cooler (bluer) will look brighter (the eye is more sensitive in that range) but neutral-to-warm will do better showing you close to the actual color of colored subjects

FmC is right; how far apart in time were these bought?

Since I don’t have 4 identical batteries, I charged two Nitecore batteries with the same Nitecore charger and did 1v1 testing, using different hosts, but that shouldn’t make any difference I guess.

Test was done on the building next to my house (light grey wall), around 30 meters apart, also on two other buildings, about 150 meters and about 200+ meters away.

XPL V3 is the brightest, relatively cool temperature.
XML2 U2 is the second brightest, looks neutral temp.
XML U2 and XML T6 are the least bright, both look identical in terms of light output, but T6 is cooler. The interesting is that despite being cooler temp, the T6 does not look brighter than the U2.

I’m sorry to waste your time, maybe I should have done that test before starting a new post. I hope at least I was helpful for some people.

I found this drop-in: http://intl-outdoor.com/p60-dropin-module-cuxm2-xml2-p-740.html

I see they offer U4 drawing 3.04A. Do you guys think it would be brighter than the XPL V3? It’s rated up to 4.5V and the SolarForces are rated up to 9V. I have no idea if that makes any difference. I plan to use them with 1x18650 only.
Or should I order SolarForce V6, which is rated less lumens than the SolarForce V3? I’m really confused now.

The SF dropins are/were pretty conservatively driven.

That IOS one should have noticeably more output. It’s a top-bin emitter, driven at ~3 Amps.

Thanks for the advice. Ordered one…