This mod is provided by Hans B. (K.). Thank
you!
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| This is a 2 steps mod of the Dorcy Metal Gear 3 AAA Flashlight.
The picture shows the chance of this flashlight casing - more
room for better batteries. 3 AAA Cells are not really the best
choice to supply a LED, rest doing that at 1 Watt or possibly
a bit more. The brightness is quickly decreasing during battery
lifetime - the standard behavour of alkaline primary batteries.
So what about 2* 123A Lithium? The case looks for enough spare
room |
Any mod for other batteries depends on the possibility of
easy demounting of the light - which luckily can be done easily.
The head of the lamp can simply be unscrewed - given you have
strong but non-scratching grip on case and head.Any mod for
other batteries depends on the possibility of easy demounting
of the light - which luckily can be done easily. The head of
the lamp can simply be unscrewed - given you have strong but
non-scratching grip on case and head. |
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| The casing reveals its Luxeon secrets - a standard 1 Watt
application. After unscrewing the hexagon with some matching
tool the LED holder comes out and reveals another spacy cavern. |
And there it is - the additional room in the in length (approx
10 mm ) necessary for 2* 123A instead of the AAA Cells. |
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| That is the idea - the longer batteries can fit taking some
of the space of the lamp cavern, the battery diameter is indeed
less than that of the the AAA casing. |
The milled parts for the mod. The aluminum part replaces the
lamp cavern, its height is about 11 mm. The battery holder is
just a piece of pipe - in this case as well milled, but every
tube starting from glued rolled cardboard to plastic tube with
the right diameter would fit for both pieces. |
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| Finally, to reveal the secret whats inside of the proud big
LED cavern - its simply a current limiting resistor. The new
shorter cavern still gives enough room for the resistor, but
the value has to be changed. The two lithium 123A have about
6 Volts instead of the 4,5 Volts of 3 AAA. The old resistor
is 1 Ohm, the new one has to be 2,2 Ohm minimum, otherwise the
maximum current will be to high. |
The new lamp housing with the new resistor and a connection
plate - copper layered board cut to a round disk. With the 2,2
Ohm the current with fresh batteries is higher than the starting
current with fresh AAA, and it will decrease slower. That gives
some sort of turbo to the brightness, but I have still to check
if the LED is happy with this. The power loss in the resistor
is doubled - sad enough lots of the gained battery power of
the Lithium cells will just heat the world. |
| So far stage one of this mod - replacing the battery
for gaining higher brightness and longer battery lifetime. Yet,
the power loss in the resistor is nagging, and sure the room
in the lamp housing is big enough for a step-down converter:
and this will be stage 2 of this mod. |
