Service batteries

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

Battery capacity: [Ah]

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
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:

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

aku_service_wzor, where

P – power [W],

t – time [h],

Un – 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.

 

Author: Daniel Czarkowski