Obviously there are individual problems which lead to certain solutions. The general issue here was charging cruiser's batteries. And this of course goes back to the typical and exceptional use of stored batteries.
Most yachts have two banks and many have a separate starting bank. This enables the yacht to use the engine
to charge the house bank even when it is deeply discharged. High output alternators do this with less run time and fuel consumption
Obviously a cruiser will have to decide how much electricity to use, how to minimize this and then devise a strategy to top off the batts.
The argument that being anchored out in the middle of no where you can run your generator
to make some quickie amps and then some ice is kinda silly since chances are that you won't have a supply of gas after a while out there in paradise. So then you have to store a lot of it and we all know the dangers of gasoline.
Setting up a wood shop on a beach and is AC power tools is another odd reason to carry a genset. While it's a hoot to have a table saw and a drill press and a jointer, it's not something that most cruisers really need. In fact today many power tools are using 12 or 14 volt batteries.
So the charging question becomes one of weighing the options and doing a cost benefit analysis including such things as initial cost, maintenance
, repair and spares, weight, "output", fuel
cost and even environmental impact including noise
and greenhouse gases.
Using the diesel
doesn't seem like an advantage when you look at fuel, maintanence, repair, environmental impact over a gen set, but since you already have one and presumably the fuel storage
thing worked (your fuel tank) and it doesn't need to invert AC power (energy loss) to charge the batteries either. And you can capture energy and create hot water
as part of the deal.
Solar is expensive initially as is a wind
gen which is a mechanical system and has maintenance
costs and each are dependent on the environment
to give up energy, wind or sun so unlike a gen set you are not using stored energy (in gasoline) to charge your batts. Wind and solar are "free" energy and though you can't get at when YOU want, over time the intial costs of the capture systems per amps they provide goes down and down, while gen sets remain dependant on the cost of gasoline and we know where that is ultimately headed.
I have cruised and lived aboard in the Caribbean
and never felt the need for more charging than I got from my diesel
and two solar panels
. I don't stay at marinas
so I was anchored out for years. I also was not especially miserly with my power use, but I didn't have a freezer
nor air conditioning
. My engine drive refer worked fine (still is) 19 years on. ON the other hand I had plenty of hot water
and had as many hot showers as I wanted. What I did do was balance by use with replenshment options and this means I ran the motor
1+ hrs a day. This begins by making an average daily electrical
use calculation. I don't have a 12v refer / freezer
and don't have air con which requires enormous power.
Of course the tropics yeild a lot of solar energy and wind as well, though less of the later in protected anchorages
and fuel costs are pretty high down there too.
I don't think a generator back up is a bad idea, but it's not on my list of priorities for a bullet proof electrical system
. If I depended on this to charge my batts I would consider it a weak link and another motor
to worry about and rust away.