The wind is back at Horseneck Beach campground.  The reservation website did warn that “sites can be breezy.”  People who come here regularly seem to be prepared for it, as I see a lot of kites and streamers attached to poles.  The big round rocks from the beach make handy weights to keep your belongings from blowing away, too.

So we broke out the kite that we’ve owned for many years and hardly ever flown.   Eleanor admits to being a hopeless kite pilot, and Emma has surprisingly little knowledge of kites, so there was some initial confusion, but eventually up it went, and it flew very well … until the inevitable crashes in the wild rose bushes. The kite survived to fly another day.

We didn’t do much else.  In the morning, we cleaned up the Airstream and relocated it to another campsite. (We’ve booked two more days here, but that meant we had to switch sites.)  I was tied to the computer the rest of the day, editing articles for the upcoming Winter 2010 and Spring 2011 issues.  Still, working near the beach on a beautiful sunny day gives the opportunity for very pleasant breaks, walking along the seashore or just enjoying the sun and salty breeze blowing through the trailer.

We had thought that in the evening we might hit one of the local restaurants for another seafood dinner, but of course being post-Labor Day, all of the tourism-related businesses are closing or reducing hours.  We settled for some interesting takeout from the local grocery and a movie at home.  It has gotten very quiet here, and that’s nice.

Solar report:  Since not much is happening, I’ve got an opportunity to talk a little more about solar.  Forgive me if this topic bores you, but I get a lot of inquiries from blog readers, so I know there is a need for real-world information.  Yesterday was full sun again, and with our 230 watt panel array, at this time of year (when the sun angle is still fairly high), we really can’t store all the power we generate.

We started Tuesday morning with a 36.0 amp-hour deficit, which is fairly normal as a result of using lights, water pump, and laptop the night before.  During Tuesday I was on the laptop for at least six hours, consuming about 9-10 amp-hours in total, and Eleanor used probably another 3-4 amp-hours charging her laptop.  Still our batteries were at 99% by 5 p.m., indicating that we generated more than 50 amp-hours during the day.

That’s all well and good while the sun shines, but the other half of a solar charging system is storage.  You’ve got to have battery capacity that is matched to your power needs and the capacity of your panels.  Long-time blog readers know that since January 2010 we have used a single Lifeline GPL-4D, which has a rated capacity of 210 amp-hours.  Today (Wednesday), we will see that half of the system put to the test.  The forecast is for gloomy skies and rain — in fact, it just started to rain as I am typing this.  Under the rain cloud, our power generation has been cut from 8-9 amps when sunny to a miniscule 0.8 -2.1 amps (depending on the thickness of cloud).  Essentially, at this moment we are generating only enough power to make up for the parasitic drain that is inherent in all modern RVs.  So, under those circumstances our power supply would be entirely reliant on the battery.

We started today with a deficit of 34.7 amp-hours. If we generate no power today, I would expect the battery to be drained by a further 20-30 amp-hours by 5 p.m., just as a result of my laptop use and normal parasitic drain. (Parasitic drain comes from the circuit boards and always-on electronic modules in the stereo, refrigerator, thermostat, propane leak detector, etc., and totals about 0.5 amps per hour.)  Tonight, we will use another 25-35 amp-hours, which means we could end up tomorrow morning with a deficit of 80-100 amp-hours.

Ideally you never want to discharge the battery by more than 50%, which means that at 110 amp-hours we need to either find some sunshine, or plug in to power.  If we are not cognizant of our power budget today, and the weather continues as it is, we’ll be up against that limit tomorrow.

Now, there are three practical responses to this.  (1) We could add more battery capacity.  A second Lifeline GPL-4D battery would double our capacity, but at the cost of about $500-600 and 135 pounds of added weight.   Also, given the rating of our solar panels, we would be hard pressed to recharge a deficit of 110 amp-hours under typical conditions.  Certainly we’d never be able to do it in a single day.  So our batteries and panels would not be well matched, although that’s not a big problem.

(2) We can plan ahead.  For example, we know that tomorrow we are pulling out of the campground and relocating.  There’s a very good chance that we will get at least partial sunshine while we are towing, which will yield power for the batteries.  (The tow vehicle does not add a significant amount of power to the batteries while towing, by the way — that’s sort of an urban myth.)  Or, if we know we are going somewhere that we can plug in, we don’t need to worry about reaching our power limit tonight.

(3) We can cut our power usage.  I could relocate to a coffee shop somewhere and use their power for my laptop.  I could take the afternoon off.  We could use only the LED lights in the trailer tonight.  We could use the campground showers to avoid using the power-hungry water pump in the trailer.  I find that a lot of people hate conserving because it makes them feel deprived, but we don’t mind so much.  If I’m “forced” to quit work early, I can live with that.

But I probably won’t get that excuse.  That’s because, in the real world, the weather changes.  It probably won’t stay cloudy all day.  Even as I’ve been typing this, the rain has stopped and some breaks have appeared in the skies.  Right now we are generating 6-8 amps, which is a very healthy rate for recharging the Lifeline. Despite fluctuations, we should generate at least enough power today to offset my laptop use.

It’s important to consider this, because people who don’t like solar power tend to invent worst-case scenarios to “prove” that it is impractical, and those scenarios often include cloudy skies.  That’s like proving generators don’t work when the gas tank is empty.  Especially in the northeast and northwest, it is quite possible to have extended cloudy periods that make solar impractical, but even in those cases it is useful.   The point is not to have unlimited power capacity.  For us, solar is a tool to enable us to camp peacefully while silent, maintenance-free power streams into our batteries automatically and extends our time in a great spot like this one.