Page 426 - Battery Reference Book

Non-reserve batteries 39/3
Magnesium dry batteries are now finding wide- are activated, to use reserve batteries fairly soon, as
spread use in military communications equipment. they undergo self-discharge.
With Increasing use and production, the cost of these Reserve batteries are recommended for use in
batteries has dropped significantiy. For example, for portable transceivers, locator beacons, electronic
the BA4386/U battery consisting of 16 long C-size counter measures and expendable electronic equip-
cells, the cost dropped from $12.50 per battery to ment.
below $5.00 over 3 years. The equivalent zinc battery
costs approximately $3.00.
Attempts to fabricate magnesium dry cell batteries 39.2 Non-reserve batteries
using flat cell constructions have to date been unsuc-
cessful. This is due to an expansion problem caused Recently, Marathon have announced a battery for mil-
by the build-up of reaction products. itary use. It is being used in equipment exposed to
There are two main types of primary battery: the tropical conditions. The most important magnesium
non-reserve type3 which is ready for use off the shelf battery now in production by Marathon is the BA4386,
and requires no activation or pre-use conditioning, and which serves as the power source for the PRC 25 and
the reserve type, which usually contains the active PRC 77 transceiver sets, formerly powered exclusively
electrode materials but requires the addition of water by the BA386 carbon-zinc battery. The BA4386 bat-
or an electrolyte just before use. tery consists of 18 CD-size cells in a series-parallel
construction. It is used by the military not only because
esewe batteries it has greater capacity per unit volume and weight
than its carbon-zinc counterpart, but also because of
Manganese dioxide-magnesium perchlorate reserve- its superior storage life both at normal and at higher
type batteries are available from Eagle Picher. temperatures.
The advantage of reserve manganese diox- Applications for non-reserve batteries include fire
ide-magnesium perchlorate batteries is that they can and burglar alarm systems, barricade lights, lantern and
be stored for years in an inactivated condition (that flasher applications, small d.c. motor applications, such
is, longer than the non-reserve type) and require as tape recorders, toys, etc., light packs for emergency
activation with the electrolyte before use. However, slide crates in commercial aircraft, and emergency
unlike the non-reserve type, it is necessary, once they location transmitters on aircraft.