Runtime Guide · Updated July 2026
What Can a Solar Generator Run? — Complete Runtime Guide
One of the most common questions from new buyers is “will a solar generator actually power my fridge / CPAP / sump pump / window AC?” The short answer is: it depends on the generator's capacity and the appliance's wattage. This guide breaks down exactly what runs on a 1,000 Wh, 2,000 Wh, and 5,000 Wh power station — and how long each appliance lasts.
Runtime Reference Table
The table below shows typical running watts, surge watts, and estimated runtime on three common solar generator capacities. All runtime figures assume ~85% inverter efficiency and continuous draw — real-world runtime will be longer for appliances that cycle on and off (like a fridge).
Figures are typical ranges based on manufacturer and EnergyStar data. Runtime estimates assume ~85% inverter efficiency and do not account for other loads running simultaneously. Appliances with compressors (fridge, freezer, AC) cycle on and off, so real runtime is often 2–3× longer than the continuous-draw estimate.
Appliance-by-Appliance Runtime Guide
Every appliance is different. Here's what you need to know about the most common devices people run on solar generators.
Refrigerator
A modern EnergyStar refrigerator draws roughly 100–200W while the compressor is running, but it only runs about 30–40% of the time (this is called the duty cycle). That means the average hourly consumption is closer to 45–80 Wh, which extends runtime considerably. The bigger challenge is the startup surge: when the compressor kicks on, it can draw 600–1,200W for a split second. Any generator you choose must be able to handle that surge or the fridge won't start.
Recommended capacity: A 1,000 Wh unit like the Jackery Explorer 1000 V2 can run a fridge for 5–8 hours, which is enough to keep food cold through a brief outage. For 24+ hours of fridge coverage, step up to 2,000 Wh+.
CPAP Machine
CPAP machines are some of the most solar-generator-friendly appliances you can own. Most models draw just 30–60W (about the same as a light bulb), and they have no startup surge because they don't use a motor or compressor. A heated humidifier adds 15–30W to the draw, but even then the total is well within any mid-size generator's comfort zone.
A 1,000 Wh unit can power a CPAP for two to four full nights, depending on whether you use the humidifier. For longer trips or multi-night outages, any generator in the 500–1,500 Wh range will give you worry-free sleep. See our full camping solar generator guide for models that pair well with CPAP use.
Pro tip: If your CPAP uses a DC power supply (cigarette-lighter adapter), plugging into the generator's 12V DC port instead of the AC outlet avoids inverter efficiency losses and can extend runtime by 15–20%.
Window Air Conditioner
Window AC units are the most challenging common appliance for solar generators. A 5,000 BTU unit draws around 500W running, while an 8,000–12,000 BTU unit can pull 1,000–1,400W. The compressor startup surge adds another 1,000–1,400W on top of that, which means you need a generator with at least 2,500–3,000W peak output.
Even then, runtime is limited: a 2,000 Wh generator might run a window AC for roughly 90 minutes at full draw — useful for cooling a bedroom before sleep, but not for whole-day cooling. For extended AC runtime, you'll need a 3,000 Wh+ system paired with solar panels to recharge during the day. The Anker SOLIX F3000 with its 3,072 Wh capacity and 4,860W surge is one of the few mid-range units that can reliably start and run a small window AC.
Sump Pump
A 1/3 HP sump pump draws 800–1,050W while running and can surge to 2,500W on startup — that startup spike is the main hurdle. If your generator's peak output can't clear it, the pump won't start even if the running draw is well within spec. You'll want a generator rated for at least 2,500W peak output for a standard 1/3 HP pump.
The good news: sump pumps run intermittently based on water level, not continuously. During a storm, a pump might run for 10–20 seconds every few minutes, which drastically reduces the actual energy consumed. A 2,000 Wh generator can realistically keep a sump pump running through a moderate storm. For heavy, continuous rain where the pump cycles frequently, a 3,000 Wh+ system like the EcoFlow Delta Pro 3 gives you much more headroom.
Furnace Fan / Blower
Your furnace fan (or blower motor) is essential during winter outages — without it, your furnace can't circulate heat even if the burners are working. Most residential furnace fans draw 300–600W while running, with a startup surge of 800–1,500W as the motor spins up.
A 1,000 Wh unit gives you roughly 1.5 hours of continuous fan operation, but crucially, the fan doesn't run constantly — it cycles with the furnace. In practice, a 1,000 Wh generator might keep your furnace running for 4–6 hours of real-world thermostat cycling. For overnight winter outage coverage, a 2,000 Wh+ unit is much safer.
TV, Router, and Small Electronics
Low-draw electronics are where solar generators truly shine. A modern LED TV uses roughly 100W. A Wi-Fi router and modem combo draws just 10–20W. A laptop charger pulls 45–90W while charging and far less once the battery is full. None of these have startup surges, so you don't need to worry about peak output.
A 1,000 Wh unit can power a TV and router for 8–10 hours of continuous use, or a router alone for 2–3 days straight. This makes even the smallest solar generators incredibly useful for keeping your family connected and entertained during an outage. Any generator on the market can handle these loads with ease.
How to Calculate Your Own Runtime
You don't need to be an electrician to figure out how long a solar generator will run your gear. There's a simple formula that works for any appliance:
Runtime (hours) = Battery Capacity (Wh) × 0.85 ÷ Appliance Running Watts
The 0.85 factor accounts for inverter efficiency — about 15% of the battery's energy is lost during the DC-to-AC conversion. If you're powering a device that uses a DC power adapter (like many CPAPs and routers), you can use 0.95 instead since there's no inverter loss.
Example Calculations
Example 1: CPAP machine on a Jackery Explorer 1000 V2
1,070 Wh × 0.85 ÷ 50W = 18.2 hours
Realistically, with the humidifier off and 8 hours of use per night, that's over two full nights on a single charge.
Example 2: Refrigerator on an Anker SOLIX F3000
3,072 Wh × 0.85 ÷ 150W = 17.4 hours
But since a fridge only runs ~30–40% of the time (compressor cycling), the real runtime is closer to 43–58 hours. That's nearly two full days of food preservation.
Example 3: Window AC on an EcoFlow Delta Pro 3
4,096 Wh × 0.85 ÷ 1,000W = 3.5 hours
With compressor cycling (AC runs roughly 50–70% of the time depending on outside temperature), expect 5–7 hours of real cooling — enough to get through a hot afternoon.
The Duty Cycle Factor
Many appliances don't draw their rated wattage continuously. Refrigerators, freezers, AC units, and sump pumps cycle on and off based on temperature or water level. This duty cycle is the single most important factor people overlook when estimating runtime.
To estimate real runtime: calculate the continuous-draw runtime using the formula above, then divide by the duty cycle. For a fridge with a 35% duty cycle: 17.4 hours ÷ 0.35 ≈ 50 hours. That's the difference between "my generator can barely run a fridge" and "my generator keeps my food cold for two days."
Recommended Generators by Capacity Tier
Not sure what size generator you need? Here's how to match capacity to your typical appliance load.
Anker SOLIX C300 DC
Best for phones, tablets, LED lights, small fans, and a Wi-Fi router. These ultra-portable units are great for camping weekends or single-device backup.
Capacity
288 Wh
AC Output
300 W
Surge
600 W
Jackery Explorer 1000 V2
The sweet spot for CPAP, a small fridge, TV, router, and device charging. Enough capacity for overnight CPAP use plus daytime essentials.
Capacity
1,070 Wh
AC Output
1,500 W
Surge
3,000 W
Anker SOLIX F3000
Run a fridge, freezer, CPAP, TV, and lights simultaneously. Ideal for multi-day outages where you need food preservation plus medical device coverage.
Capacity
3,072 Wh
AC Output
3,600 W
Surge
4,860 W
EcoFlow Delta Pro 3
Fridge, sump pump, furnace fan, lights, and router — all at once. Suitable for partial-home backup during extended outages.
Capacity
4,096 Wh
AC Output
4,000 W
Surge
4,000 W
Anker SOLIX E10 Prime Off-Grid Kit
Whole-home capable systems that can run multiple large appliances simultaneously. Designed for full off-grid living or multi-day whole-home backup.
Capacity
12,000 Wh
AC Output
7,680 W
Surge
10,000 W
Still not sure? A good rule of thumb: if you're only running small electronics and a CPAP, a 500–1,000 Wh unit is plenty. If you need fridge plus a few essentials, go for 1,500–3,000 Wh. For whole-home or multi-appliance backup including pumps or AC, you'll want 3,000 Wh+. And if you're planning to go fully off-grid, the 5,000 Wh+ tier with solar panels is your starting point.
Written by Alex Rivera · Senior Technology Analyst · Updated
Frequently Asked Questions About Solar Generator Runtime
How long can a solar generator run a refrigerator?
A standard EnergyStar refrigerator (150W running, ~35% duty cycle) will run for roughly 5–8 hours on a 1,000 Wh generator, 10–16 hours on a 2,000 Wh unit, and 25–40 hours on a 5,000 Wh unit. The duty cycle is the key factor — because the compressor cycles on and off, real-world runtime is typically 2–3× longer than a continuous-draw estimate. For multi-day fridge coverage during an outage, we recommend at least 2,000 Wh of capacity paired with solar panels for daytime recharge.
Can a solar generator run a CPAP machine all night?
Absolutely. A CPAP machine draws just 30–60W (no surge), so even a small 300 Wh generator can power one for a full 8-hour night. A 1,000 Wh unit gives you 2–4 nights of CPAP use on a single charge. For the best runtime, use your CPAP's DC power adapter (cigarette plug) instead of the AC adapter — this avoids inverter efficiency losses and can extend runtime by 15–20%. Heated humidifiers add 15–30W to the draw but are still easily managed by a 500 Wh+ generator.
Will a solar generator run a window AC unit?
It can, but it's challenging. A small 5,000 BTU window AC draws 500–600W running but surges to 1,500–2,000W on startup. You'll need a generator with at least 2,500W peak output to start one reliably. Even then, runtime is limited: expect roughly 1.5 hours from a 2,000 Wh unit or 4 hours from a 5,000 Wh unit. For extended AC use, you'll want a 3,000 Wh+ system with solar panels to recharge during the day. The Anker SOLIX F3000 (3,072 Wh, 4,860W surge) is one of the few mid-range units that handles window AC well.
Can I run a microwave off a solar generator?
Yes, but most microwaves draw 800–1,200W while running, which means they consume your battery quickly. A 1,000 Wh generator can run a 1,000W microwave for roughly 50 minutes of total cook time — but since you only use a microwave for 2–5 minutes at a time, that's dozens of heating sessions. The bigger concern is ensuring your generator's AC output wattage can handle the microwave's draw. Most 1,000 Wh+ units with 1,500W+ AC output can run a microwave without issues. Just don't expect to cook a full Thanksgiving dinner on a small generator.
How long will a 1,000Wh power station last?
It depends entirely on what you're powering. A 1,000 Wh generator will run a CPAP (50W) for 16–30 hours, a TV (100W) for 8–12 hours, a fridge (150W, cycling) for 5–8 hours, or a Wi-Fi router (15W) for nearly 3 days. For mixed use — say, CPAP overnight, TV and router during the day, and a few device charges — a 1,000 Wh unit comfortably covers about 24 hours of typical outage needs before requiring a recharge.
What size solar generator do I need for my home?
Start by listing the appliances you must keep running during an outage. For a fridge, router, lights, and a CPAP, a 1,000–2,000 Wh unit will cover you for a day. If you need a sump pump or furnace fan, step up to 3,000 Wh+. For a window AC, well pump, or whole-home coverage, look at 5,000 Wh+ systems with 240V split-phase output. Use the runtime formula above to calculate your specific daily watt-hour budget, then choose a generator with at least that much capacity — ideally 1.5–2× your daily needs to give yourself a buffer for cloudy days when solar recharge is slow.
Can a solar generator run a space heater?
Technically yes, but practically it's not a great use of your battery. Space heaters draw 1,500W continuously, which means a 1,000 Wh generator would run one for only about 30 minutes. Even a 5,000 Wh unit only lasts about 2.5 hours — and that's using the entire battery. A much more efficient approach for winter outages is to power your furnace fan (300–600W) instead, which uses a fraction of the energy. If you must use electric heat, a propane or kerosene heater is a better choice, or use an electric blanket (100–200W) which provides personal warmth at a fraction of the power draw.
Does a solar generator need solar panels to work?
No. A solar generator is first and foremost a battery. You can charge it from a standard wall outlet before an outage and use it like any other battery backup. The "solar" in solar generator refers to its ability to accept solar panel input for recharging, which makes it possible to extend runtime indefinitely during extended outages. For short, predictable outages (a few hours to a day), pre-charging from the wall is perfectly adequate. For multi-day or indefinite off-grid use, solar panels are essential.