Hello all,
Today i am going to present my third lantern of the K series. Generally K-series, is the result of further improving my lantern making technique and addressing a bunch of issues as
* increased luminosity with more efficiency
* dimming down to few lumens
* replaceable led bulbs
* using high efficiency LEDs of still warmer white color
* simpler electronic design
Overally, the vintage outlook of the lantern is pretty much the same as the previous series i.e. modified petroleum hurricane lanterns, but the above attributes were achieved after hard work and lots and lots time of experimentation in order to put all together despite the inherent restrictions of making such lanterns.
About the KΓ lantern
........
Chassis: Standard 30cm height (12''), plain type, reinforced with standard glass treated so as to be semi-frosted (antiglare) and labeled
the "bulb": An improvised LED fasten-heatsink 5-sided element that has mounted x 15 (5 each side) 2323SMD Samsung SPMWHT221MD5WAW0 see datasheet here
http://www.led1.de/shop/files/Samsung/SPMWHT221MD5WAW0S0.pdf
Ahhh... those tiny and rather expensive SMD leds are a pain to be handled and soldered without damaging them. But the light they emit is almost heavenly. Warm white (2700K)
That improvised bulb is mounted on a GU10 male socket that fits on a porcelain female socket permanently fastened on the lantern chassis. If ever for some reason the bulb is damaged, easily can be replaced, let aside
the fact that LED technology improves month after month so the 125 lumens / watt of this bulb could be easily 200 or even 250 in few years.
the batts: ΚΓ lantern once open the bottom lid, takes in a similar fashion with all lanterns made by me so far, takes 3 x C alkaline batteries of 1.5 volts each. They are calculated to last according energizer's datasheet around 12 hours
at max.
the circuit: A use of MC34063A boost controller IC, that inputs from 4.5 volts down to 2.5 volts whereas providing stable power output around 1.35 watts. Its efficiency is around 85% at max setting and in lowest voltage.
(meaning in most current draw for those who know about electronics). In other words, lamp's brightness is undiminished irrelevantly of batteries' status (unless exhausted). At that power lamp shines with 140+ lumens at
max.
Minimum luminosity is less than a lumen. Once closed (FET switched) no quiescent current. The circuit needs some 25mW to run. Once the bulb is removed circuit will stay idle (no burn). A pot is attached to circuit for
voltage level adjustment (power out restricted)
weight: Less than 900gr with batteries (2 pounds)
...
Forgive my tech enthusiasm but i am an enthusiast
i made this lantern having in mind those who want a vintage, unique made lamp, robust, that needs no maintenance (higher power rechargeable li-cells needs), that will stay year after year in place and when it is needed it would be there to provide all the light you need and create an wonderful atmosphere. Also being independent of charger will continue happily to light once supplied with a fresh set of batteries.
photos:
Cheers,
Barou
ps:
http://rechargeable-led-lantern.com/?p=205