Boy that is a good question! The best answer I have so far is that if I could find a slightly used Fischer Panda 4200 Mini, I could move the water heater back in the port cockpit locker (or perhaps to the starboard side) and put the gen set where the water heater is. That would give me just enough room to perform maintenance and I would still be able to squeeze into those lockers to maintain other systems. The reason I would have to go with the older FP is that it is small enough to fit! The newer EPA certified engine makes the replacement model 2" higher, 3" wider and 4" longer... Just enough to make me think twice! The NexGen 3.5 is simply too long for my use and Mase makes a small gen set that is interesting but it is designed so that maintenance would be a nightmare in my installation. Before anyone tries to warn me about the complexity of the Fischer Panda line, I should mention that I have intimate knowledge of a couple of these units. I can cope with them...
As for all the suggestions about solar panels, I am sure they would help but every dealer I have spoken to says that I would need in the order of 300 to 400 watts of panels to do what I want. That is a lot of panels! If I price the high output flexible kind I quickly get to a number north of $4000 for the panels alone! The output on the latest Soliban panels is warranted for 5 years now, not bad I guess.
I understand that there are less expensive choices out there but for a number of reasons I am not interested. Too, sometimes we take the Bimini down and solar panels mounted on the fabric would make that challenging.
I have simply run the engine for these past ten years to charge batteries. As I said earlier, this makes me a little crazy! It is less the sound of he engine than the knowledge that the engine is unloaded and thus actually being abused. It is no problem for a short weekend to run in the bulk phase of the charge just to keep the batteries between 50% and 80% but on longer stays when making water, loading the fridge regularly, playing the stereo, charging phones... You eventually have to pay the piper. It is not unusual for us to use 100 to 150 amp hours while at anchor! I guess I should be embarrassed to admit that but the reality is, that is what happens.
The Superwind wind generator has had a nice impact on our energy bank as a I am sure solar would too.
I will probably simply install the A/C for this season and continue to run the engine. The reality is that unless we decide to budget energy (what a concept!!!) we will likely be running an engine for charging in some way.