Off Grid
Solar panels
Most solar panels come in one of two varieties: monocrystalline and polycrystalline. Mono panels are slightly more efficent but also more expensive. Where space is not a concern, poly panels can be cheaper or sized up to provide more energy at a given cost. Ironically, the cheaper poly panels sometimes outperform mono panels in conditions of partial shade or obstruction.
Renogy 100 watt solar panel (mono)
- 100 watts (nominal)
- Monocrystalline
- Dimensions: 42.2 X 19.6 X 1.38 in
- Compact form factor
- Weight: 14.3 Pounds
- Input voltage: 17.9 Volts
- Maximum System Voltage: 600V DC (UL)
Gas generators
WEN 56475 4750-Watt Portable Generator
- 4750 watts
- Dimensions: 26.6 x 17.1 x 17.3 inches
- Weight: 112.5 Pounds
- Engine displacement: 223 Cubic Centimeters
Wind turbines
Dyna-Living 24V 800W Wind Turbine Generator
- 800 watts max, substantially less in most conditions
- Min wind speed: 2 m/s (about 5 mph)
- Rated wind speed: 13 m/s (about 30 mph)
- Max wind speed: 50 m/s (about 110 mph)
Human power
Human power is a very inefficient way to generate electricity. In some situations, such as extended natural disasters, it can be better than nothing.
K-TOR Power Box 50
- Rated 50 watts, realistically about half that with sustained pedaling
Energy storage
Lead-acid deep-cycle batteries may be used for stationary energy storage at home. Lithium is still more expensive for a given amount of energy storage, but lithium has advantages in portability, safe discharge depth, and long-term battery life.
Mighty Max 12V 35AH deep cycle battery
- Capacity: 35 AH
- Dimensions: 7.68 x 5.16 x 7.13 inches
- Weight: 23.2 pounds
Charge controllers
There are two main types of charge controllers: PWM and MPPT. The difference is that MPPT is about 20% to 30% more efficient than PWM in converting the voltage from the solar panels (or other source) to the optimum voltage for charging batteries. However, MPPT is also more expensive than PWM (often hundreds of dollars vs. tens of dollars), so it's usually not worth using in small installations where those hundreds of dollars could double or triple the size of the solar array instead.
In larger installations, an MPPT controller can pay for itself with the efficiency gained. And if the total cost of electricity is not a priority, MPPT controllers are also useful for making better use of a limited amount of production capacity.
Renogy Wanderer Li 30A 12V PWM Negative Ground Charge Controller
- For charging and monitoring a 12V battery system
- Handles up to 30 amps
- Dimensions: 6.45 x 4.31 x 1.76 inches
- Weight: 0.65 lbs