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The Conversion of Aquaflashes to take Nicad Rechargeable Batteries.

by Trev Hughes.

A standard aquaflash, using three cells, gives a light output of 1.35W when using a standard bulb but, if converted to take rechargeable nicad batteries the light output is increased to 3.6W.  I have a catalogue advertising 4 Ah cells for about £4.50.  A normal dry cell costs about 35p so the increased light output is not the only advantage.

The actual conversion process is quite simple and can be done on the kitchen table (if you're a bachelor, Ed:).  The only tools required are a saw (for cutting plastic), a small rat-tail file and a craft knife, plus a sheet of sandpaper.  The operations are as follows:

1)         Mounting the Bulb

A pre-focus/screw thread bulb converter is required (I have plenty to spare) and a metal washer cut as shown in fig la.  These allow a 3.6V 1 A bulb to be fitted to the standard reflector.  The plastic bulb holders must be adapted to fit into the reflector's back.  The inner hole is enlarged to the external diameter of the bulb converter and, to allow for the extra thickness of the washer an equal amount must be removed from the end of both pieces (fig 2).

2)         Fitting the converted Reflector

When mounted in the reflector the bulb protrudes past the edge.  A spacer must be made to ensure that the bulb clears the screw down torch lens. A piece of plastic drainpipe or similar to the sizes shown in fig lb is used.  It is most easily made by sanding down the rough sawn annulus on a sheet of sandpaper resting on a hard, flat surface.  To compensate for this spacer the torch body must be shortened by a similar amount to ensure that the "0" seal does not leak.  To complete the job the brass contact strip is shortened by the same distance.

I have tested my converted torches in Wookey Hole and Freke's Cottage well to 80 feet, and to 110 feet in the sea off Poole with no leaks.

If anybody requires 4Ah nicad batteries (U2 size) I have the details.  If a large order can be sent then the unit cost is reduced.