13 days without hookup (6 in Anza Borrego SP and 7 in Death Valley) and I can report a couple of things.
First of all, we had very little sun. Our site in Anza Borrego was fully in shade because of a hill from 1:30PM onwards. In Death Valley, we had site #58, which is highly rated for the shade provided by one of the few trees - a good thing in the summer, but not perfect for solar. So overall, the best scenario for testing our fuel cell setup.
Other observations in bullet points:
• we used about ⅔ (1.8G) of methanol.
• the fuel cell hums and we did only run it once over night.
• our energy consumption is much higher than I previously stated (wrong estimate) - we use in total about 70-80Amps.
• the battery rarely went below 70% (our system is calibrated for the 200Ah battery and it tells us: a) the current draw (or charge) in amps, and b) the amount of amps from full. So with a fully charged battery we have, in theory, 200Ah at 100%.
Shown below is a typical scenario for pretty much 11 of the 13 days:
9:13AM - battery is 43Ah from full (watching TV at night, plus the fridge - despite running on propane - draws about 1amp/h, other leaching devices add about 0.6amps/h)
11:49AM - battery is 29Ah from full
Solar is lousy - 1.7A charge current
BUT fuel call PLUS solar (minus fridge etc draws) produces 3.8A charge current:
Usually, at night (6PM), the battery was >90% charged. On three days, we made it up to 100%.
Only on one night, we only made it back to 85% charge (about 30Ah from full); here we decided to run the fuel cell over night. We started the morning at 10Ah from fuel and caught up to 100% at about mid day.
• I also noticed that the Efoy was producing 3.0A at maximum - it mostly lingered at 2.9A. This means that in 24h, the maximum Ah output from the Efoy80 is 24x2.9 = 70Ah.
So, overall, running the fuel cell from wake up time (about 7AM) until bedtime (around 10PM) was pretty much giving us a free mind about our battery charge situation. We were attentive about our electricity use but we did not conserve energy. We had the inverter running from about 7PM until 11PM with one or sometimes both TVs, plus the Apple TV. We used the Keurig or Nespresso coffee makers 3-4 times during the days. The furnace was running only in the early morning hours (usually from 5AM until 7AM).
Is this setup good for everyone? Probably it depends on your habits and the climate. For Western US camping, the Efoy80 is certainly sufficient as an add-on to a good solar system during the winter months. If running the furnace is required for most of the night, I probably would look into the Efoy140 or 210 models, which produce more power. But then the methanol consumption is probably going to go up and hauling multiple 10 liter cartridges of methanol is probably not very convenient (and expensive). For us, I believe that we found a good winter setup.