I agree with David - separate and properly sized systems if you have the real estate and $$: House bank sized to handle 12v and inverter loads for the duration needed. genset starter battery main engine(s) starter battery - I prefer one for each, but one is not an embarrassment. Relying on the genset to start the mains (or the reverse) is not comforting (I know!) co-located windlass/hoist battery(s) (optional) Isolators and combiners to make it easy to recharge (and power the inverter) the house bank from main propulsion engines. Switch if you want manual control. Nice set of jumper cables when you gotta go below and get going if 'stuff happens'. Separate chargers (or legs) for each bank, or they do not get fully topped off. Readily available distilled (or rain or dehumidifier condensate) water for topping off electrolyte. Good digital meter for testing. I also like my inductive amp meter (12 vdc design) to confirm current flows during sanity checks. Has two scales: 0-50 and 0-300 amps. My $.03. Jim In a message dated 8/19/2009 12:00:46 A.M. Eastern Daylight Time, trawlers-and-trawlering-request@lists.samurai.com writes: A big bank for house loads and a separate battery for starting your main engine all tied together with a combiner or isolater for a "set and forget" solution is the way I would go.