We have run an off-grid homestead in Montana for twelve years. In that time we have used all three formats — hand-crank radios during shoulder-season outages, a solar generator setup through summer fire season, and a propane generator when back-to-back cloudy days wiped out our solar buffer. None of them is universally right. Each wins in a specific scenario and fails you in others. If you are still deciding what to buy before the next outage, start with the 72-hour blackout checklist to nail down your total load, then come back here to settle the format question.
This comparison is not about brand names or review stars. It is about which energy format fits your geography, your load, and your safety situation. Get the format right first. Equipment shopping comes second.
Why the 72-Hour Window Changes Everything
A 72-hour outage is long enough that hand-waving does not work, but short enough that you do not need to solve every energy problem — just the critical ones. Critical loads for most households are: refrigeration (keeping food safe), communications (phone charging, weather radio), lighting, and one or two medical devices if applicable. Space heating, air conditioning, entertainment — those are comfort items, not survival items.
A standard full-size refrigerator draws roughly 100–150 watts while running, cycling on and off to average around 1–2 kWh per day depending on ambient temperature and how often it gets opened. A smartphone charges at about 5–18 watts. An LED replacement lamp pulls under 10 watts. Your actual critical load for 72 hours likely falls in the 3–6 kWh range — a completely manageable number if you choose the right format.
Where people go wrong is trying to power the whole house. A propane generator running central air in summer will burn through fuel in ways that make a 72-hour scenario expensive and complicated. Size to critical loads only.
What Hand-Crank Power Actually Gets You
Hand-crank generators and hand-crank radios get misunderstood as serious backup power. They are not. A hand-crank emergency radio with a built-in generator produces in the range of 1–5 watts while you are actively cranking. That is enough to charge the internal battery for a few minutes of radio reception. It is not enough to charge a modern smartphone to useful capacity in any reasonable amount of time.
Where hand-crank earns its place: communications. A quality hand-crank NOAA weather radio is one of the most reliable pieces of emergency equipment you can own. No sun required. No fuel. No grid power. It delivers weather alerts and emergency broadcasts regardless of conditions. Every prepared household should have one — full stop — regardless of what other backup power they choose.
The honest verdict: hand-crank is a communications tool, not a power tool. We would not build a 72-hour power plan around it for anything beyond radio reception and minor device trickle-charging.
Solar: The Silent Workhorse With One Hard Dependency
A solar generator — a lithium battery pack with an integrated inverter, charged by portable solar panels — is the best format for most suburban and rural households in clear-weather climates. No exhaust. No fuel storage. No noise ordinance headaches. You can run it indoors safely. The battery stores energy overnight or through short cloud cover, and panels recharge it daily as long as sun is available.
The single hard dependency is sunlight. A 72-hour outage during a Pacific Northwest winter storm with three days of heavy overcast will not let you recharge. In that scenario a solar generator works through day one on stored capacity, struggles on day two, and may fail you on day three. If your region regularly produces multi-day overcast during outage seasons — ice storms, nor'easters, blizzards — solar alone is not a complete solution.
The DOE recommends working with qualified installers to assess solar potential at your specific location, noting that output depends on local sun hours, system orientation, and efficiency. The same logic applies to portable solar setups: a 200W panel in Phoenix produces meaningfully more energy per day than the same panel in Seattle in January. Know your peak sun hours before betting your food supply on solar.
Propane: The Most Watts per Dollar, With Real Safety Strings
A dual-fuel or dedicated propane generator gives you more wattage for less money than almost any other format. A 3,500-watt propane generator costs a fraction of what a comparable solar generator runs. It can handle a refrigerator, several lights, and a phone charger simultaneously without breaking a sweat. Runtime is predictable: you know how many hours per tank, so you can plan your fuel supply for exactly 72 hours.
The safety strings are real and non-negotiable. Propane combustion produces carbon monoxide — a colorless, odorless gas that is dangerous when it accumulates indoors. OSHA's electric power safety guidance identifies carbon monoxide as one of the documented hazards associated with combustion-based power equipment, alongside electrical hazards and thermal burns. Running a propane or gasoline generator indoors, in a garage, or in any partially enclosed space is a documented cause of CO poisoning.
Propane also requires fuel storage. Storing large propane cylinders safely requires appropriate outdoor storage away from structures and ignition sources, following standard safety practices. If you live in an apartment, a dense urban area, or a place with HOA restrictions on outdoor fuel storage, propane may not be practical regardless of cost.
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Calculate your critical loadAdd up the wattage of everything you actually need to run: refrigerator, phone charger, medical devices, lighting. Multiply average watts by 72 hours to get your watt-hour requirement. Most households land between 3,000 and 8,000 Wh for true critical loads.
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Assess your sun reliabilityLook at historical weather patterns for your outage season. If your region typically gets fewer than 3 peak sun hours per day during winter storms or major weather events, solar cannot reliably recharge in time. Cloudy-climate households need propane or a hybrid approach.
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Check your combustion spaceDo you have outdoor space at least 20 feet from doors, windows, and vents where you can run a generator safely? Apartment dwellers and dense urban households without safe outdoor generator space should not use propane or gasoline generators — solar or battery-only is their only real option.
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Evaluate your fuel storage situationPropane requires storing cylinders outdoors in a well-ventilated area away from structures. If HOA rules, municipal codes, or physical space make this impractical, cross propane off the list regardless of cost advantages.
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Match format to scenarioClear-weather climate + outdoor space = solar generator with propane backup. Cloudy-climate + outdoor space = propane primary with solar supplementing in good weather. No outdoor space = solar generator only. All three households = add a hand-crank NOAA radio regardless.
- Size your battery or fuel supply for the full 72 hours
For solar: buy a battery with at least 1.5x your 72-hour critical load to account for depth-of-discharge limits and cloudy recharge days. For propane: calculate runtime per tank from the manufacturer spec at your expected wattage, then buy enough tanks for 72 hours of actual run time (not 24/7 — you run it in cycles, not continuously).
- Test before the outage, not during it
Run your chosen system on a clear day under real load before an emergency. Confirm the refrigerator stays cold on solar or propane cycling. Confirm your fuel lasts as calculated. Problems discovered during a test are inconvenient; problems discovered on day two of a real outage are dangerous.
Common Mistakes That Strand People Mid-Outage
The most common mistake is buying a solar generator sized for marketing watt-hours rather than usable watt-hours. A 1,000 Wh LiFePO4 unit gives you roughly 800–950 usable Wh at 80–95% depth of discharge. A 1,000 Wh AGM-based unit gives you roughly 500 Wh before you risk damaging the battery. Read the chemistry before comparing prices.
The second mistake is powering only electricity while neglecting water. A working refrigerator does you no good if you don't have safe water. Power your backup pump or water heater if needed, and have a plan for boiling water safely — especially relevant if propane is also your backup cooking fuel. If municipal water is disrupted alongside the power outage, you also need to understand water filtration vs purification before you need it.
The third mistake with propane is running the generator inside a structure "just for a few minutes" because it's cold or raining. Carbon monoxide builds up faster than people expect. There is no safe duration for indoor operation. OSHA's electric power safety documentation classifies combustion-related gas hazards as a serious workplace hazard category; the same chemical risk applies in residential settings.
The Hybrid Approach Most Serious Preppers Use
The households that handle outages most reliably do not choose just one format. We use solar as the daily workhorse — silent, no fuel, no exhaust — with a small propane generator as the emergency backup for extended overcast or high-load situations. The hand-crank radio sits on the shelf year-round and gets tested every few months. Each format covers the other's weakness.
This is not a budget recommendation — it requires buying two systems. But if you are in a climate with unpredictable weather during outage seasons, the hybrid approach is the only one that delivers true 72-hour resilience without hoping for good weather.
Can a hand-crank generator actually charge a smartphone?
A hand-crank emergency device produces 1–5 watts while actively cranking, far below the 5–18 watts a modern smartphone draws during charging. You can top off a nearly-full phone over a long cranking session, but a dead phone will take many hours of continuous effort to reach useful capacity. Treat hand-crank as a communications tool for weather radio, not a phone-charging solution.
How much propane does a 3,500-watt generator use per hour?
A 3,500-watt propane generator running at half load typically burns around 0.4–0.6 gallons per hour, though actual consumption depends on the specific engine and load level. A standard 20-pound barbecue cylinder holds about 4.7 gallons of propane. At half load that gives you roughly 8–12 hours per cylinder. For a 72-hour outage running 8 hours per day in cycles, plan for at least two standard cylinders.
Is it safe to run a solar generator indoors during an outage?
Yes. Solar generators — battery packs with integrated inverters — produce no exhaust and no carbon monoxide. They are designed for indoor operation. This is one of the key advantages over propane and gasoline generators, which must only be operated outdoors in well-ventilated locations far from windows, doors, and vents. If indoor operation is a requirement, solar is the only safe choice.
What size solar generator do I need to keep a refrigerator running for 72 hours?
A standard refrigerator averages roughly 1–2 kWh per day, so 72 hours requires 3–6 kWh of usable storage. For a LiFePO4 battery at 80% depth of discharge, you need a rated capacity of 4,000–8,000 Wh. Add phone charging and lighting and you are looking at a 2,000–3,000 Wh rated unit as a practical minimum for most households, assuming some daytime solar recharge. Without recharge, size to 1.5x your 72-hour load.
What is the safest distance to run a propane generator from my house?
Propane and gasoline generators should be operated at least 20 feet from doors, windows, vents, and any opening into a structure. Exhaust should point away from the building. This distance is widely referenced in generator safety guidance as the documented minimum to prevent carbon monoxide from entering occupied spaces. Install a battery-operated carbon monoxide detector inside the home whenever operating any combustion generator nearby.