ScrimpyJack

looking for advice before i set sail and leave my marina and try continual cruising this year, I have a 3kw inverter with 570w of solar panels and been spoilt with mains supply and ever ready tank of hot water. When Ive been out cruising I've always struggled after a few weeks to keep my batteries topped up, and have to run the engine now and then. Presumably our continual cruisers run their engines or use a generator to get hot water... do you recommend an affordable generator to do this and how long do you need to run it to top the battieries up and get a tank of hot water from the calorifier. Im not technical when it comes to solar charge or plumbing so any advice would be helpful. apologies if this has been asked before.