I have been contemplating this for years and I finally decided to splurge and I will add a fuel cell to our setup.
Our 25FB has 400W solar on the roof (4 flexible Zamp panels), a Blue Sky 3000i MPPT charge controller, and 200Ah AMSolar Li-battery bank.
The system is in place for almost 2 years now. It works flawlessly; the 1000W stock Airstream inverter is sufficient for our use, even for running our Nespresso machine including the milk frother
The only issue is that when we hit extended cloudy weather periods, are camping in a forest, or in the winter, we use up our battery resources relatively quickly. Running the furnace in cold nights adds more to the load. With 50Ah use and only 15Ah replenishment by the solar system, we are down to 50% of the battery's capacity after 3 days. Our water usually lasts for 8 days, we can stretch it to 10 days before we need to empty the waste water tanks, so the challenge is either to be very conservative with our energy consumption, add more Ah to the battery, or to buy a generator. We cannot go beyond 250Ah in battery capacity without major upgrades to the electrical system.
We are towing with an SUV (Pepper, our 2014 Cayenne Diesel) and after almost 50K miles towing, I am absolutely confident that the Cayenne was the right decision [but this is another thread that needs some updates].
So, a generator (probably a small Honda 1000i @ $800) would be the way to go, but it requires regular maintenance, comes with the smell and the need for fuel, etc. Still, absolutely, the generator would be the fiscally responsible and logic solution. Without a truck, we would still have to figure out how to transport it, it requires effort each time we use it, etc.
As mentioned, I have been playing with the idea of a fuel cell and even started a thread years ago but besides rumors and smartypants comments from people who like the technology but do not find that it is a feasible solution (all kinds of reasons), there was pretty much nothing that was available with respect to first hand experience. I browsed some European boards where fuel cells are being used in RVs and the reviews are perhaps falling into 3 categories:
1) Happy users
2) Unhappy users (mostly people who "froze" their fuel cell in winter times and needed repair)
3) Critical non-users who mainly complain that they are sweet but the costs are prohibitive
Well, here we are. The order for an Efoy 80i fuel cell kit has been placed today!
The system incl tax costs 4x as much as an equivalent (I know not comparable really) small generator, so upfront costs are high. The boss agreed to this (my B-day and X-mas present combined) and with the promise that she can run the hair driver from now on...
I plan to post here my first hand experience with the system, which I plan to use during a 14 day boon docking trip over Christmas and New Year.
I ordered the smallest fuel cell that provides 80Ah over 24h when continuously run, which should be ample to "trickle charge" my battery system when the solar panels are just not providing sufficient power. In November, the maximum output of my solar panels was 8A, but the average output of a full day ranged from a minimum of 10Ah (clouds) to 18Ah (sunshine but early sunset because the sun was blocked by a hill). With a use of 50Ah (maxing it out with running "stuff"), I hope that running the Efoy for half a day would be sufficient to get by batteries fully charged each day, continuously.
One cartridge of methanol fuel (10L, 2.64G @ $70) should be sufficient to generate 760Ah, so the costs of replenishing 10Ah will be around $1. Not sure how this compares to a generator (probably lousy and costly). But, we use the system perhaps 8-10 weeks per year, about half of the time the sun will be out. This results in 4-5 weeks (35 days max) of about 20Ah (estimated) = one cartridge per year. Hopefully no other maintenance - the system should be plug and play.
Cartridges are available at iMarine with free shipping (although when I ordered it stated a $40 surcharge for dangerous goods, but it did not show up on the final bill - will see how this works out). I am not sure whether the cartridges can be re-filled with (high quality) methanol from other sources, certainly something that will be discussed in the future.
Ok, this is setting the stage. I will post pictures when the stuff arrives.