Funny this topic should come up - Over the past week, I've been converting several of the Dorcy/Ozark Trail lanterns that Wal-Mart sells for $3.50 (including battery) to operate on a single white 20 mA LED. The idea is to have a cheap, reliable light that will run for several hundred hours, at some sacrafice in brightness over the original Krypton bulb.
Right now, I'm using a dropping resistor to limit the LED current, but eventually will be installing a LP2951 regulator instead. As part of the modifications, the lantern battery is glued in place for maximum drop-resistance, and all connections are soldered. The pushbutton switch in these lanterns has a very solid feel, and should last a while.
big beam said:
You should be able to tell by the balance of the battery.If it's top heavy it has d's in it.If it's balance is in the middle it has f's.I think the spacer is in the bottom.
The Dorcy Mastercell 4R25 "Heavy Duty" battery that is included with these lanterns has a center of gravity approximately 1/3rd of the way up from the bottom. However, I've drilled a peek-hole in both the top and bottom of one of these batteries, and both ends appear to be completely filled with cells. This particular battery sells for under 2 bucks at Dollar General stores, but since Wal-Mart throws in a brand-new flashlight for just a buck and a half more...