4D Maglite to 4x18540 (14.8v) with Superbrightled 1W LED 7-30v

I read this from another forum post back in 2011:

“superbrightleds has a couple of PR LED bulbs.
PR2-1WHP-30V. Flange base 1 Watt High Power Cree XRE Cool White LED. 1 to 9 Volts DC and 7 to 30 Volts DC. 100 lumen.
I recommend the 7-30V as buck regulators are more efficient and probably brighter.
PR2-3WHP-9V. Flange base 3 Watt High Power Cool White LED. 3.5 to 9 Volts DC operating voltage range, 180 lumen. 110 degree beam pattern”

I’m trying to convert all my D-Cell Mags to 18650 simply because I found a cheap source of 18650s and I’ve already got the charger.

Originally I didn’t think my 4D Mag was going to get an LED conversion because of the cost of finding something that could handle 15v, but these Superbrightled 7-30v 1w LEDs may make it possible to convert the whole fleet to 18650.

My only worry would whether the switch/wiring of the Mag could handle that voltage. Any thoughts?

Cheap 18650 and 4 cells in series in a sealed Maglight sounds like a pipe bomb to me.
Stick with a 6V LED and 4 NiMH rechargeables.

I’m thinking of running 4 quality protected batteries, would that be any better?

Yes, if they are really high quality cells, and they are protected, that should be okay. But, the LED bulb you cited is only a 1W LED. It won’t put out much light and for runtime you would still do just fine with alkalines or NimH rechargeables. If you do use 18650’s to power it, one would be plenty. There is no need to use four.

I expect that the voltage would not be an issue until you got to hundreds or maybe thousands of volts.

You could vent the tailcap to help with pipe-bomb action in the event of a failure. If you found a source for “cheap 18650s” then they are very likely not “quality protected cells.” (And I only trust the protection so far.)

As has been pointed out… this project seems a little iffy. What’s the general idea? The proposed bulb will give stock brightness (stock bulb is 105 lumens), not even the brightness of a mild aftermarket bulb.

Have you considered building something like a Mag623? You could also build an ROP with two 18650 and a battery spacer for something milder, or IIRC you could even use the L bulb from the Pelican 3854 pack to get an even milder build. You still might want to vent that tube though.