I got this from instructables.com see the link for the whole article at the end. The author believes with the modification you can get 60 days of useable light at 6 hours of use a day!
ITEMS NEEDED
- Eveready Floating LED Flashlight 5109LSH7/5109LS
- Resistor (56 ohm)
- Soldering Iron
- Extra 6 volt Battery (because we are preppers! always have backups! as we said in the military 2 is 1, 1 is none!)
HOW TO BUILD
STEP 1
Unscrew the Black right that holds the light of the flashlight on the front. Remove the light assembly (seen in photo) put in the Battery and put it back together, to test and make sure it works.
Then re-remove the light assembly and rind as shown in the picture above. Unsolder on or the two red wires from the metal contact (what the arrow is pointing to in the photo)
STEP 2
The resistor chosen was 56 ohm which reduced the power to the LEDS to 50 milliamps (from 180 milliamps)However you dont have to use a 56 ohm, a 44 ohm (two in series) would reduce the power to 56 milliamps and 100 ohm would reduce it to 31 milliamps, it all depends on what you want to do. The fewer the milliamps the less power, longer life, but also reduced light intensity.
Solder on end of the resistor to the metal contact on the light (bright metal on left) and the other end to the wire that you removed in Step 1. Re assemble the Light. You are don!
RESULTS
The Left beam is from an un-modified verson while the one on the right shows the decreased light capacity in the modified version.
The original creator ran the light 24 hours a day and found that after 15 days (360 hours) there was still useable light, but noticeably dimmer than when the experiment started. He estimates that if used 6 hours a day you could get 60 days out of this thing!
CONCLUSIONS
Its not a perfect fix, we all want LONGER LASTING and FULL POWER, however that isnt going to happen! However I see this as a good use for around the house for daily chores, going to the bathroom, etc. Have a Backup FULL POWER light for say checking for intruders or that bump in the night. But 60 days of useable light is VERY GOOD!
Original article can be found here.
Apparently the same guy who did the flashlight mod in your article did another one that is the happy medium between really bright and long run time. The test picture for the comparison between the modified 10 LED and the half watt maglight seems to indicate that for about 6 dollars you can have maglight brightness and way over 100 hours of run time:
http://www.instructables.com/id/Rayovac-Bright-10-LED-Mod-150-Hours-Under-600/?ALLSTEPS
This is a great article. I decided to try it with a 220ohm resistor and it’s still plenty of light and has been on for over 2 weeks now!!! Keep up the cool project ideas! Thanks!!