The other day a friend of mine stopped by with a problem he thought I could help him out with. He's a servayer and his old style military type flashlight wasn't up par with the new LED flashlight. What to do? Take that new LED flashlight (freebie) and put the guts into the old flashlight.
*the only extra parts I needed was some wire, a 3AAA battery holder and some 1in. SCH40 PVC pipe.

Step 1: Take It Apart

This is the easy part. CHECK THE PHOTO

Step 2: Wire Up the Lens

1. DESOLDER SPRING off the LED PCB and save for use later.
2. Take the LED PCB and solder on some wire leads
a. NEGATIVE to the OUTSIDE CIRCLE of LED leads
b. POSITIVE to the INSIDE CIRCLE of LED leads
3. Take the OLD LENS and drill a hole ( big enough for the POSITIVE WIRE LEAD ) somewhere near the metal contact ring.
4.a. Thread the NEGATIVE WIRE LEAD thru the rear of the old bulb holder.
b. Thread the POSITIVE WIRE LEAD thru the hole drilled near the contact ring.
5.a. SOLDER the NEGATIVE WIRE LEAD to the metal part of the old BULB HOLDER.
b. SOLDER the POSITIVE WIRE LEAD to the metal CONTACT RING.

It's ok if the LED lens floats, it will self center and tighten up when reassembled.

Step 3: The Battery

The problem: The old flashlight uses 2 D cell batteries and the LEDs use 3 AAAs.

The solution: Find another battery holder like the one that came out of the freebie flashlight and run those two series battery circuits in parallel.

THIS IS EASIER TO DO THEN IT IS TO EXPLAIN

1. SOLDER a WIRE LEAD to the POSITIVE end of one of the battery holders
2. SOLDER a WIRE LEAD to the POSITIVE end and a WIRE LEAD to the NEGATIVE end of the other battery holder.
3. HOT GLUE the POSITIVE battery holder ends together.
4. HOT GLUE the POSITIVE WIRE LEADS down and out to the negative end with the wire lead.
5. HOT GLUE the NEGATIVE WIRE LEAD down and out to the negative end without the wire lead.
6. SOLDER the NEGATIVE WIRE LEAD to the edge of the negative end.

Step 4: The Battery Holder

1. Cut a 4.5 in. piece of 1 in. SCH40 PVC pipe.
2. DRILL a 1/16th in. hole into one end of pipe.
3. REMOVE 2 negative and 1 positive caps off of the D cell batteries.
4. SOLDER the SPRING to the outside end of one of the negative battery caps.
5. Take the positive wire leads from the battery and run thru the plastic gasket thing that came off one of the batteries.(this is an insulator, very important)
6. DRILL a 1/16th in. hole near the edge of the other negative battery cap.
7. SOLDER the POSITIVE WIRE LEAD to the inside end of negative battery cap with hole.
8. SOLDER POSITIVE BATTERY CAP and NEGATIVE BATTERY CAP with spring together, let cool and HOT GLUE to PVC pipe end without drilled hole.
9. Put battery into new battery holder NEGATIVE end first.
10. Screw the new positive cap to the PVC pipe.

Step 5: Reassemble

1. Reattach the lens assembly.
2. Slide new battery holder with batteries NEGATIVE end first.
3. Reattach the base of the old flashlight and go have some fun in the dark.CFH