Lamar Technologies D-1560 - Manual (Page 3)

II. OPERATION PREFACE
NOTE: RATINGS AND EXAMPLES GIVEN IN THE PREFACE BELOW MAY DIFFER
FROM THE USER OR BATTERY MANUFACTURERS’ REQUIREMENTS.
Discharge current capacity testing is the only valid method of determining
the true reserve (emergency) capacity of a battery. Reserve capacity is especially
important for aircraft which may have to depend on the battery for emergency
power in the event of power failure. The battery must deliver usable power for one
hour.
This is often also important for various ground support equipment and
military vehicles. Most aircraft batteries are 24 volt sealed or vented lead acid, or
NiCad. Military vehicles have 12 volt lead acid batteries which may be combined
for higher voltages and amperages. The 5160 accommodates both 24 and 12 volt
batteries.
An acceptable reserve capacity will also reflect upon the high current
capability of the battery for engine starting and possible other short time high amp
loads. However, the reverse is not necessarily true. An acceptable high current
cold cranking amp test, whether acceptable by hand-held conductance or
impedance test meters, or 15 second CCA load test, does not automatically
translate into an acceptable reserve test.
Both the military and FAA mandate reserve capacity testing for aircraft
batteries. This may be done by removing the battery from the aircraft for testing
every 600 hours of use. The test essentially loads a fully charged battery with a
full ampere-hr rated load. E.g. 40 amp-hr battery drawing a 40 amp load for 1
hour. The battery must deliver full power until the voltage drops to an unusable
level such as when relays and instruments drop-out. This can be at 18 or 20 V.