What angle should my solar panels be?
For year-round use, tilt them up from flat by roughly your latitude. More precisely, for most of the US (latitudes 25 to 50 degrees) the best fixed angle is your latitude times 0.76 plus about 3 degrees, which comes out a little flatter than your raw latitude. For example, at 40 degrees north the optimal year-round tilt is about 34 degrees, facing true south. The calculator above gives the exact figure for your latitude, along with steeper winter and flatter summer angles if you are willing to adjust twice a year.
Should RV or van solar panels be flat or tilted?
Flat is fine if you move every few days, camp mostly in summer, or travel at southern latitudes, because the year-round loss from flat mounting is only about 10 to 15 percent and you skip all the fuss. Tilting is worth it if you live off-grid full time, rely on solar through the cooler months, park in one place for a while, or travel up north, where a flat panel can lose 40 to 55 percent of its output in midwinter. RV owners who tilt have measured winter gains of 33 to 42 percent. If you mostly camp in summer, adding another flat panel is often easier than tilting.
What is the best winter solar angle?
Steeper than your year-round angle, because the winter sun sits low in the sky. A simple rule is your latitude plus about 15 degrees. For maximum December output the precise figure is a bit steeper still, around your latitude times 0.875 plus 19 degrees, which at 40 degrees north works out to roughly 54 degrees. A steep winter tilt has a bonus on the road: it sheds snow better than a flat panel, which can otherwise sit covered for days.
Which direction should solar panels face?
True south in the northern hemisphere. Note that a compass points to magnetic south, which can be off from true south by as much as 20 degrees depending on where you are in the country, so correct for your local magnetic declination using the free NOAA declination calculator. The good news is that facing is forgiving: being 15 degrees off true south costs only about 1 percent a year, and 30 degrees off costs a few percent. A flat panel has no direction at all, so aim only starts to matter once you tilt.
Is a solar tilt mount worth it?
It depends on how you travel. A tilt mount (about 30 to 60 dollars per panel) earns its keep if you are stationary for stretches, live off-grid full time, use solar through winter, or camp at higher latitudes, where it can add 30 percent or more to your output. It is usually not worth the hassle for summer-only trips or if you move every day, since you have to set the panels up and take them down each time, and an unattended tilted panel can catch wind. For frequent movers, oversizing a flat array by roughly a third often beats tilting.
How much energy do flat solar panels lose?
Over a full year, a flat (zero-degree) panel produces roughly 10 percent less than one tilted at your latitude in the south, about 15 percent less in the middle latitudes, and 20 to 25 percent less up north, by clear-sky estimates. The annual figure is modest because a flat panel still collects diffuse light from across the whole sky. The real penalty shows up in winter, when the sun is low: a flat panel can produce 40 to 55 percent less than a steeply tilted one. So flat mounting costs you the most exactly when you tend to have the least sun.
How often should I change my panel tilt?
Hardly ever, for most people. A single angle set to your latitude already captures about 71 percent of what a two-axis sun-tracker would produce. Flipping between a summer and a winter angle just twice a year raises that to about 75 percent, which is nearly all of the available gain. Adjusting four times a year adds only a fraction of a percent more, and daily fiddling is not worth your time. Set it and forget it, or at most switch it twice a year, around late March and mid September.