I got my SEEKNITE S11 GITD a few days ago. Bought it for $12.99 from Banggood using Fin17’s code:
I also bought some identical looking ones (not GITD though) from AliExpress but they have not arrived yet. I suspect that this flashlight is sold under many brands, such as Alonefire S11, BORUIT S11, etc. but I couldn’t find any teardowns for them so I can’t be sure.
Generally speaking, I mostly like this flashlight. It is very similar to the NITECORE TIKI (UI is almost the same) and not too much bigger:
I have drawn a chart for the UI:
I don’t have any way to measure lumens output but it is brighter than the TIKI on turbo.
I don’t have a way to measure color temperature either, but it doesn’t look like 6500K to me. My guess would be around 5000K-5500K. It is warmer than the TIKI and I think the TIKI is lower than 6500K.
The GITD works well, although I don’t find this feature useful at all:
The Auxiliary white LED is CW, unlike the TIKI. The UV light IS UV, but it’s UV component is weak and it’s not as “clean” as the TIKI. My guess is that it has purple wavelengths in addition to the UV (just like the sunlight has all the colors, including UV). I tried to capture the difference with my camera but While the XANES KT and the S11 light looks about the same to my eyes as the photo, the TIKI came out very different, in real life it is not only much brighter, but more things light up in the money bill. You can, however, see in the S11 photo that there is visible purple:
The tail magnets do hold the flashlight horizontally, but any small bump or shake will make it drop.
Teardown:
Disassembly is very easy, just unscrew the metal head (mine was partially undone already ), remove the heatsink+TIR lens and then push from the USB port and the whole innards will slide out:
The thread is lubricated, I lack the experience to say if enough, though. The SST20 LED looks genuine to me:
Only the sides of the the bare copper have thermal compound on them (not sure why):
Some of the battery markings are faded but most of them are intact. The battery is marked “701040 3.7V 260mAh (0.9)62Wh DD10”:
The circuit board looks pretty simple:
I have not measured anything but I’ll make some assumption as to how it works just by looking at the photo:
The big unmarked SOP-14 IC is the (unknown) MCU. It runs the 5 LEDs with PWM via the five A2sHB MOSFETs (the SOT-23-3 packages), the primary LED has an additinal 0.5Ω current limiting resistor (two 1Ω in parallel). The SOT-23-5 IC marked LTH9 is the charge controller (probably TP4054). The battery protection is on a small PCB in the battery, I have not opened it but my guess would be a DW01+8205S duo.
I measured 228mAh on the battery, discharged from full to 2.7V at a constant resistance of 71Ω:
I charged the battery with an external charger at 128mA (read the last paragraph to see why). The capacity discrepancy is probably because the manufacturer rates the battery with a slower discharge and/or to a lower voltage (E.G. C/10 to 2.5V).
Funny thing though, the battery measures only 38.5mm x 10mm x 6mm, not 40mm x 10mm x 7mm as the marking implies.
Charge current is about 500mA:
That seems too much to me. I don’t know the specs of the battery but I have doubts as to it’s longevity with this much current. I barely charge my Li-Ion batteries with 1C, let alone 2C like this flashlight.
If I could be assed, I would change the 2K resistor (marked 202) next to the TP4054 with a 4.7K one to get a 198mA charge current, but I can’t, so I won’t.
Also, since the TP4054’s termination current is one tenth of the charge current, it means it will terminate the charge at 50mA, so the battery will never be fully charged to 260mAh (my guess would be around 240mAh).
[update: Aug. 23rd 2021]
I have received the non-GITD S11 that I bought from an AliExpress seller for $10.97 (free shipping), but before I begin I would like to correct a couple of things: first, the UI chart has a slight omission: you can switch to each mode from the other, I.E. double-press while the side lights are on will turn on the main LED, and triple-press while the main LED is on, will turn on the white side light.
Also, I forgot to mention the S11 has a low battery warning, the charging LED will turn green for a few seconds in any of the modes if battery voltage is higher than 3V, and red (blinking) if it is below. The red will also blink if the battery < 3V while the flashlight is on.
The S11 from AliExpress is slightly different. The package claims a different main LED, the Samsung LH351B:
And it does indeed looks like it is:
Judging by djozz’s photo:
The color temperature is also different. It is cooler. I would guess about 6000K to 6500K.
I couldn’t see or feel any lubrication on the threads or the O-ring, so the waterproofing is questionable (might still comply with the stated IP65 though).
Ultra-Violet is about the same, strong light, but most of it is in the visible range:
Once again, I tried to capture the TIKI’s UV but no matter what I did I couldn’t take a photo that shows what my eyes see. I did, however, manage to take one photo where the TIKI’s light shows more UV activated things light up:
(These glowy lines light up all over the note easily with the TIKI but not at all with the S11)
The board is slightly different, but pretty much the same:
The battery is the same. I didn’t see any reason to test the capacity again, it’ll just be the same:
I can say for a fact that the protection circuit works well, because I accidentally shorted the battery wires (oops) and the battery output was turned off and did not reset until I connected it to a charger.
That sums up the differences. In addition, I have made some further tests:
Quiescent current: The flashlight draws about 1uA from a fully charged battery when off.
Main LED current draw (from the battery):
Economic: 7mA.
Low: 38mA
Medium: Starts at 150mA, but within a few seconds starts ramping down slowly. This doesn’t seem to have anything to do with heat, it is completely time based.
High: Starts at 500mA , but within a few seconds starts ramping down quickly. This doesn’t seem to have anything to do with heat, as using cooling (fan) doesn’t change the time it stays on 500mA and also turning the flashlight off and on immediately as it starts throttling down doesn’t change anything as well.
Turbo: Starts at 750mA and after a while, starts throttling down. I didn’t measure the time but I would estimate it’s about 30s to 1min.
UV: 260mA.
I also measured the white and red side LEDs but after re-assembling the flashlight I discovered that I forgot to write the values down ( :person_facepalming: ). Sorry.
Please note: These values were measured with a Ruideng DPS3005. It is an amateur power supply and I don’t know how well it handles the PWM measurement, so take these numbers with a grain of salt.
This time I actually took the time to change the 0603 charging resistor:
(Don’t judge my soldering… It’s very small and I didn’t use any magnification)
And now I like the charging current much better:
A weird thing happened though, before I re-assembled the flashlight, I did another test with the PSU and noticed that all the currents were lower than what I measured earlier, E.G. the turbo was about 600mA and the high was about 400mA.
Maybe I damaged something when soldering the new resistor? I don’t believe the actual change to the resistor could have had any such effect.