Selection of service accumulator batteries

Required power [W]	Required time of service [h]

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Battery capacity: [Ah]

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Rated voltage:	Type of battery:
24 V	Lead-acid of large surface caonstruction
12 V	Lead-acid with latticed structure plates
	Alkaline
	Alkaline with low internal resistance

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Temperature of electrolyte:

25 °C, batteries placed on board of ships sailing in the tropical zone,

15 °C, batteries fitted on board of ships sailing in unrestricted zone,

5 °C, batteries fitted on board of ships sailing in unrestricted zone or operated in moderate zone and installed in the engine room or compartments to heated by adjacent rooms,

-15 °C, batteries fitted on board of ships sailing in unrestricted zone or operated in moderate zone and installed in non-heated rooms,

-25 °C, batteries fitted on open decks on ships other than sailing only in the tropical zone.

Temperature coefficient, a= , assumed:

Discharging time coefficient, b= , assumed:

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Calculations were carried out based on the Polish standard PN-W-89509:1997 Merchant ships, batteries, selection, in accordance with the following equation:

, where

P - power [W],

t - time [h],

U_n - rated voltage[V],

a - temperature coefficient (curves are available in the standard) taking into account reduction of the capacity due to electrolyte temperature,

b - time coefficient (curves are available in the standard) taking into account reduction of the capacity in time.