47 CFR 80.862 - Proof of capacity.
(b) Proof of the ability of a battery used as a main or reserve source to operate continuously for 6 hours can be established by a discharge test over a prescribed period of time, when supplying power at the voltage required for normal and operation to an electrical load as prescribed by paragraph (d) of this section.
(c) When the reserve power supply is an engine-driven generator, proof of the adequacy of the engine fuel supply to operate the unit contiuously for 6 hours can be established by measuring the fuel consumption for 1 hour when supplying power, at the voltage required for normal operation, to an electrical load as prescribed by paragraph (d) of this section.
(d) In determining the electrical load to be supplied, the following formula must be used:
(1) One-half of the current of the required transmitter at its rated power output.
(2) One fourth of the current of the automatic radiotelephone alarm signal generator; plus
(3) Current of receiver; plus
(4) Current of emergency light(s); plus
(5) Current of the bridge-to-bridge transceiver when connected.
(e) At the conclusion of the test specified in paragraphs (b) and (c) of this section, no part of the main or reserve power supply must have an excessive temperature rise, nor must the specific gravity or voltage of any battery be below 90 percent discharge point of the fully charged value.