[nkaminar]

On our sailboat the alternator was on the main engine, a Diesel. Most sailboats are set up that way. We had two huge deep discharge house batteries and a large starting battery. All were flooded lead-acid batteries. The engine was run for an hour once a day to charge up the holding tanks for the refrigerator and freezer. We had solar panels so the alternator was not needed unless the house batteries were run down because of using the inverter or other big loads. The charging curve is designed to charge the lead-acid batteries in the shortest amount of time and to their full capacity. This was years before Li-ion batteries were available. The charge controller for the solar panels had the same charge curve.

The holding tanks for the refrigerator and freezer contained a salt solution that froze and then melted throughout the day to maintain the proper temperatures.

On a sailboat the engine is used to enter an anchorage or to get to a dock at a marina. It is also used to motor when there is no wind or when trying to head directly into the eye of the wind. We motored about half the time. I hated to do it but it was necessary.