thread on another forum got me thinking....my tent fan "motor" for my ceiling fan will run 9 hours on a new D cell, but only slightly more than 3 hours on a AA Eneloop in a single cell "D" adapter... I ordered a set of the dual cell adapters, but haven't received them yet...so I put together a proof of concept, using a couple of sheet metal screws and fender washers to produce a "pack" to increase the milli Amp hours available... the pack does not need to fit in a cylindrical tube, so went with a 4 pack...the sheet metal screws are to keep the washers centered...the section of plastic tubing is a spacer... pack is held together with a piece of bicycle inner tube





I ran a duration test, and the pack ran the fan motor for 9 hours, my desired outcome, but upon recharging the Eneloops, found one had not been discharged, so evidently had not made electrical contact... so the old "three points determine a plane" has some merit... I have a much smaller bicycle inner tube, and will try a 3 pack tomorrow...which should fit in a cylindrical flashlight body...the space between the 3 batteries is quite small, might possibly find a couple of roofing nails with large enough head, or try some pre 1982 copper pennies for contacts...regards