Solar, battery & generator guides
Reference charts and plain-language guides for off-grid, RV and backup power, with the numbers worked out and links to the calculators you’ll need.
- Appliance wattage chart: running and starting wattsHow many watts does a refrigerator, microwave, AC, sump pump or TV use? Running and starting watts for home and RV appliances, with daily energy.
- LiFePO4 vs lead-acid (AGM and flooded) for solarLiFePO4 vs AGM and flooded lead-acid for solar, RV and boat banks: usable capacity, cycle life, weight, efficiency, cold charging and safety.
- 30 amp vs 50 amp RV: the watt math30 amp vs 50 amp RV service explained with the watt math: 3,600 W on one 120 V leg vs 12,000 W on two, what each runs and what generator it needs.
- Generator safety: carbon monoxide, backfeeding and transfer switchesPortable generator safety from CPSC and OSHA: carbon monoxide, where to put it, why never to backfeed through an outlet, transfer switches and refueling.
- Battery safety for solar, RV and van systemsSafe handling, charging and installation of LiFePO4 and lead-acid batteries: short circuits, BMS, charging temperatures, hydrogen venting and disposal.
- Peak sun hours by city (and what they mean)Peak sun hours for US cities from NREL’s PVWatts — yearly average, worst and best month — plus what a peak sun hour is and how to look up your own.
- Solar and battery words explainedPlain-English glossary of solar, battery and generator terms: watts vs watt-hours, amp-hours, depth of discharge, sun hours, MPPT, Voc and surge watts.
- Battery group size chart: amp-hours for group 24, 27 and 31Amp-hours for group 24, 27 and 31 deep cycle batteries from manufacturer data sheets — flooded, AGM and lithium — and what the group number tells you.
- 12V battery voltage chart: state of charge12 V lead-acid battery voltage vs state of charge from a manufacturer data sheet, with 24 V and 48 V equivalents, plus LiFePO4 charge and cut-off voltages.
- Propane tank size chart: gallons, Btu and hoursHow many gallons and Btu are in a 1, 20, 30, 40 or 100 lb propane tank, and how many hours each lasts at 10,000 to 50,000 Btu per hour.
- How to size an off-grid solar system, step by stepSize an off-grid solar system in five steps: load list, battery bank, solar array, charge controller and inverter, with a worked van example.
- Starting watts vs running wattsStarting watts vs running watts for generators and inverters: what each means, which appliances surge, and how to add them up without oversizing.