So, are lights that use 2s always half of the driver current at the tail, or just for a buck driver. I’m used to single cell models
Well, 2S batteries double the voltage while 2P keeps the voltage the same, but can double the amps. The net power (watts) is the same.
So to answer your question, usually just for the buck driver. So for example a XHP70.2 light with 2 cells with say, one of our FET+1 drivers, will have about the same amps at the tail as delivered to the LED, but the XHP70.2 is a 6V LED. But of course a buck driver can be used for a 6V LED and 2S battery flashlight, and still the measured tail amps could be about the same as delivered to the LED. The advantage of the buck driver is regulated output in this configuration so the voltage may be bucked down, but not significantly.
How bad does it look? My SF47T sample did not dent the front cell as badly but I noticed the positive terminal's surface becoming slightly concave from the high pressure of the head spring. However, it does not appear to be very serious as the outer frame of the button will still provide enough contact between two cells in series. OTOH, I would never try to use two Tesla batteries (Sanyo NCR21700A) with a soft aluminum terminal structure or two (too long) protected button top batteries in this flashlight.
Both cells fairly match with their total capacity to run in serial connection. I measured a difference of approx. 100mAh between both cells, i.e. 2% deviation.
Sofirn (Lishen) 21700 5000mAh battery, front cell:
Sofirn (Lishen) 21700 5000mAh battery, rear cell:
The spring in the head section and the double-spring in the tailcap.
BTW, Wurkkos uses the same new battery for their new TS30S (SBT90.2) flashlight.
In which flashlight will they use it?
What do you think about the tube design? I find it odd that the knurling only goes halfway up. Most of its use will be holding it how you would a side switch model and every now and then tactically. I don’t get why the knurling is non existent where it matters most.
Just after some thoughts before I make my video review.
I finished the beamshot footage last night, got inside at 4:30am. Compared the L21A, FT03 (SST40), SP70, and C8G since most Sofirn fans would have one. Not many throwers from Sofirn to compare. I found virtually no gain in range to the FT03, and the L21A was much better, but I knew that by having a larger reflector and driven at 8A.
I get 1160 on the SF47T and 1340 with the L21A.
I found a small firmware bug. double click to turbo in Outdoor UI, then hold for Tactical UI. It switches on in Strobe
First drop was at 48°C and it’s staying at 54°C with a lot of fluctuating. Not as badly as the SP33 V3 but it still needs tweaking, it’s unable to settle, it just keeps jumping up and down. You wouldn’t notice while using it which is what counts. Should have the runtime tests finished tonight. I’m aiming to have the review up by Thursday
I agree with you. Usually, the palm embraces the anterior part of the tube in tactically-held position - the part that is missing the pineapple knurling. I have not tried yet to reverse the tube but looking at the threads and tube wall diameter it will probably not fit the other way around.
Will check it on mine.
I hope to get my tests done very soon. Probably, the luxmeter (app) will reveal to what extent the output‘s amplitude is fluctuating. Maybe it will be in line with the SP35 ATR curve which was promised to be improved. Unfortunately, we need to wait a bit for SP35 to become available with ATR.
I’m pissed off. Used that ceilingbounce app and waited 4 hrs to complete a High run only to accidentally double tap the “stop test”. It overwrote the test 
I completed the Turbo run and thankfully saw the High test and the time it stopped so I’ll just create my own. High lasted 4 hrs 16 min, hit 47°C without any stepdowns, so that’s 4hrs 16min straight on High.
S**t happens, Funtastic. What app did you use for testing the output? I recently used one simply called "Lux Meter" and I was quite satisfied with it.
https://play.google.com/store/apps/details?id=de.waldau_webdesign.app.luxmeter&hl=de&gl=US
Good thing I saw the graph before it erased it. It looked exactly like this. I’ll just use this in my video review.
As you can see it started to regulate once hitting 47°C for the first 2hrs and then seemed to settle. Room temp was 26°C with no cooling
My video review will be on youtube by tomorrow night. One thing that bothers me is the tint on the SF47T is very cool white, while the L21A is a neutral white. It almost looks like it’s being pushed too hard or isn’t cooled well. It’s a neutral white until you kick it into Turbo. I think I’ll remove the mcpcb and check the surface is flat. The thermal paste is spread out all around the mcpcb which is usually a good sign.
Maybe it’s just a different bin to Convoy’s CULPM1 but blue/purple has never been a good sign for these
Jacob, how satisfied are you with the focus / centering of the emitter? I am not sure if the reflector geometry fits to the CULPM1.TG. Instead of a concentrated spot mine appears to have a bit of a washed-out spot with some artifacts / blurred corona around it. It looks like the shape of an eye with eyelids around. Hard to explain but I will provide some shots anytime soon anyway. Mine seems to get a touch of coldwhite on turbo, too. But it's still okay, not being angry™blue.
Cheers, Thomas
Have you had a flashlight using these leds before though? The artifacts are four ovals overlapping around the hotspot, this is normal on the Convoy L21A, C8, and S2. The artifacts are worse if it’s not dead center and these centering rings aren’t easy to get it 100%
I’m glad you mentioned this. We don’t talk about these things enough. I was trippin when I got my SP36 and Acebeam L30. Maybe not because of artifacts but because of things like beam shape and tint shifts too. I know it gets mentioned here and there but not enough.
I would have never known that about the Osrams, and I’ve read plenty about it all over the place. I’ve also never seen this characteristic manifested in the many beam shots I’ve seen since they all look like perfectly round lightsabers. But I know I may have been uneasy if I got one and wasn’t aware of this.
Anyway, my main point was thanks. I expect to get one at some point soon and this helped a bunch.
Decided to take a look at the driver, here’s my photos
T shaped driver - 26.4mm
23.8mm MCPCB
Tail assembly
Reflector measurements
Depth (length) - 50.5mm
Top dia - 50.6mm
Led opening - 7.9mm
How do I use custom values in an excel chart? I’m having a lot of difficulty. I used a lux app and have the csv data, selected it and inserted a chart. How do you or can you rename and add different values to the chart, such as lumens instead of the lux value, or the time values to something readable like 0, 1hr, 2hr, etc
Are you having trouble reading the file?
If csv loads badly, check if you need to change the dot to a comma or remove the apostrophe.
So do we have 3.5h on turbo (1500lm) or not? ;))