The Edna battery box is constructed from aluminium and weighs 75g without battery.
The box has a screw lid, at the opposite end to the lamp cable gland. The lid has an O ring to ensure a water tight seal.
The Edna battery box accommodates 1S1P 3.7v li-ion battery packs, using an individual 18650 cell, with battery protection circuitry and RC connector.
Single cells arrangement keep helmet weight to an absolute minimum, while providing sufficient capacity for a decent sport caving trip!
Edna battery packs are simple non-proprietary 3.7v arrangements, so the customer need not be tied to expensive proprietary battery packs, as often used by lamp manufacturers.
The Edna battery box will also accommodate individual 18650 batteries, using Edna battery holder.
For further battery guidance and charging options, see Edna Batteries
The Edna battery box can be attached to back of helmet with suitable shock cord, zip ties etc, according to user preference.
A flexible, impact tolerant approach, widely used by cavers for mounting battery boxes and battery packs on helmets!
The Edna battery box has been designed to be serviceable with fairly basic skills.
Should maintenance ever be required, then the cable gland end of the battery box can also be unscrewed, and if required the cable gland can also be readily removed. We would of course advice against disturbing the cable gland end of the battery box, other than for essential maintenance. If cable gland is disturbed then replacement of O ring (see Lamp Spares) may be necessary (or reseal with epoxy resin / gasket sealer etc).