Let’s cut to the chase shall we? So what’s special about the LUC? Well it applies the appropriate charging current based on the length of the cell. Anything longer than ~66mm gets charged at ~1000mA, else ~500mA. It achieves this by having 2 springs at the bottom of the charger. When the sliders make contact with the springs the 1000mA charging current is applied. Simple and effective.
This makes it idiot-proof so the user can’t negligently charge smaller cells like 16340 at 1000mA. And of course the bigger cells get charged faster which is a good thing. It takes way too long to charge 26650’s on 500mA chargers like Nitecore i2/i4
In case you’re wondering, the springs are purely for signalling only. No charging current passes through the springs.
The sliders allow charging of cells as short 30.4mm and as long as 71.3mm, so it pretty much cover all the common flashlight cells: 16340, 14500, 18350, 16650, 18500, 18650, 26650, etc. The LUC features raised + terminals so flat-tops are OK.
Now let’s charge up a Sanyo 14500 840mah:
The LUC features CC/CV charging. As expected the short 14500 cell charged at specifically ~480mA in the CC phase. The CV phase ended when the current dropped to below 80mA thus ending the charge like a proper li-ion charger should i.e. no trickle charging. Cell voltage upon termination: 4.21v
When charging longer cells the higher charge rate kicks in, specifically ~1020mA, and follows a similar CC/CV profile. CV phase ended when the current dropped below 250mA. Cell voltage upon termination: 4.17v
USB OUTPUT FEATURE (preliminary, more info to be added later). In a nutshell this feature seems to work well and seems to be able draw from either bay. Will add more info when I finish testing.
CONCLUSION: The LUC seems to be a good charger. The LCD is a good feature though it only has a resolution of a tenth of a volt that may be all a casual user needs. I also like the automatically-selected dual charge rates. Overall the construction seems to be very good. The sliders operate smoothly and aren’t flimsy.
However the 250mA termination current (at the 1000mA rate) seems a bit high, so the cell will finish with a bit less charge. But it also means that it’ll finish earlier and not spend too much time applying the tapering current at the end of the CV slope.
See ya! 
