Kitchen Panda
Enlightened
During a recent, rare, Internet outage, I decided to figure out why my ancient Led Lenser 3 x AAA light ( model number 7???, don't have the original packaging and don't see it cataloged anywhere any more...it's pretty old) had stopped working. This was my first "high power" LED light, bought many years ago at a Sears store in Fargo ND. It knocked around for years, but I foolishly left batteries in it and so had to dismantle it for cleaning. I got it working again, though the battery carrier looks kind of ugly. It sat in the junk drawer of my workshop since I have more reliable flashlights that haven't yet had their innards eaten.
I had a 14450-sized LiIon cell that I'd acquired from a borken vape pen. I had a vague ideal that I could use it to turn this into a rechargeable light - I even had the charging circuit from the vape, it would have been a bit of a callenge to make it all fit but a good winter project.
Did I mention "direct drive" ?
I got one brief flash of light out of it on the LiIon, then it went dark. I ran out of time to play with it and set it aside till last week.
The miniature snap-ring pliers I bought to dismantle an AAA light were too big for that, but fit this light perfectly. I unscrewed the aluminum block holding the LED and found...just that. An LED, one lead screwed to the aluminum, the other wired to the + battery carrier contact. Not even a resistor!
Obviously the internal resistance of the AAA pack is what keeps the LED from burning out...and a vape pen battery has a very low internal resistance.
Oh well. Now the project is to a) find a suitable LED b) find some kind of driver - worst case, a series resistor! c) fit the LiIon battery and charging circuit d) figure out a way to make a teeny microUSB slot in the side of the case.
After spending months of free time I will have home-brewed a rechargeable flashlight I could buy for $30 any day of the week. Maybe I'll get a UV LED or something cool like that, to make it a little less mainstream.
Bill
I had a 14450-sized LiIon cell that I'd acquired from a borken vape pen. I had a vague ideal that I could use it to turn this into a rechargeable light - I even had the charging circuit from the vape, it would have been a bit of a callenge to make it all fit but a good winter project.
Did I mention "direct drive" ?
I got one brief flash of light out of it on the LiIon, then it went dark. I ran out of time to play with it and set it aside till last week.
The miniature snap-ring pliers I bought to dismantle an AAA light were too big for that, but fit this light perfectly. I unscrewed the aluminum block holding the LED and found...just that. An LED, one lead screwed to the aluminum, the other wired to the + battery carrier contact. Not even a resistor!
Obviously the internal resistance of the AAA pack is what keeps the LED from burning out...and a vape pen battery has a very low internal resistance.
Oh well. Now the project is to a) find a suitable LED b) find some kind of driver - worst case, a series resistor! c) fit the LiIon battery and charging circuit d) figure out a way to make a teeny microUSB slot in the side of the case.
After spending months of free time I will have home-brewed a rechargeable flashlight I could buy for $30 any day of the week. Maybe I'll get a UV LED or something cool like that, to make it a little less mainstream.
Bill
