Rationing solar power

Sometimes normal awareness is not enough to keep a solar setup functioning with usable power. In these situations one might need to take steps to minimize loads and maximize power generation.

Here are some examples:

• smaller solar installations
• a stretch of rainy days
• a forest campsite with no good access to sunlight
• smoke from forest fires
• very short winter days

• find and eliminate parasitic loads
• make it a habit to turn off anything you don't need right now. Channel your Inner Dad who says “turn off the lights when you leave the room!”
• timeshift charging of phones, laptops, etc to periods of excess power
• charge light sources during full sun and use them at night
• go to bed with the sun, rise with the sun
• use low-power entertaining like reading instead of power-hungry entertainment like TV, gaming console, etc
• turn down screen brightness on phones, tablets, TVs
• Inverters
  • minimize the use of inverters by using 12v appliances and adapters when possible
  • turn inverters off when not in use
  • size the inverter to meet the needs of your biggest loads. Oversizing wastes power because bigger inverters have more parasitic draw. It may be worthwhile to have a small inverter for small loads and a big inverter for big loads; this stops the inefficient use of small loads on a big inverter.
  • use MSW unless your intended uses need PSW; MSW have lower parasitic draws.
• open your refrigerator as little as possible after sundown
• cook with propane instead of electricty

• ensure the panels are not shaded by natural obstructions: move out from under trees, overhangs, etc.
• ensure the panels are not shaded by manmade obstructions on your own RV: antennas, A/C units, vents, etc. One way to minimize shading is to park so that the greatest expanse of panel is facing south and any obstructions are on the north side of the van.
• tilt panels if possible
• ensure no tarps, awnings or other obstructions are preventing cooling breezes from passing under/over the panels; panel output drops as cell temperature rises.
• framed panels (mono and poly) should be mounted with some space underneath them for cooling airflow. Cell temperature affects panel voltage output.
• clean the solar panels. Dust or dirt on the panels can decrease panel output by 5-10% in some cases.²⁾
• tweak your PWM controller to produce more power, and be ruthless about not running loads until the battery bank is out of bulk mode.
• invest in an mppt controller if you can, and configure it to battery manufacturer specifications
• install an isolator for alternator charging
• use shore power charging (via converter) anytime it is available