I have a requirement to supply 3 battery banks to start 4 engines.
Engine 1: 24VDC, 2 x 7.5kW Starters (330ah Victron AGM Battery Bank, Skylla TG 100Amp Charger)
Engine 2: 24VDC, 1 x 6kw Starter (330ah Victron AGM Battery Bank, Skylla TG 100Amp Charger)
Engine 3: 24VDC, 1 x 5.5kw Starter (165ah Victron AGM Battery Bank, Skylla TG 50Amp Charger)
Engine 4: 24VDC, 1 x 5kw Starter (90ah Victron AGM Battery Bank, Skylla TG 35Amp Charger)
I have purchased batteries to suit those recommended by the engine supplier however I need to prove that the batteries are large enough to cope with the starting currents of each engine.
Each engine needs to be able to crank for maximum of 10 seconds for 6 start attempts.
How do I calculate this?
I also need to prove the batteries can be recharged in less than 6 hours.
I calculated the charger size with the following formula:
ah of battery * 40% charger losses / charger current