What Can a Solar Generator Actually Power? Real Wattage Guide
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The short answer: a solar generator can power almost anything that doesn't draw heat continuously. A 1,000Wh unit can run a refrigerator for 6-7 hours, charge a laptop 15 times, or power a CPAP for two nights. It cannot run a space heater for more than 40 minutes or a window AC unit for more than 90 minutes. The limiting factor is always the combination of your device's watt draw and your battery's watt-hour capacity. This guide puts real numbers on everything.
How to Find the Watt Draw of Any Appliance
Every appliance has a label — usually on the back or bottom — listing its electrical specs. Look for a line that says something like "120V ~ 60Hz 8.5A" or "900W." If you see amps but not watts, the formula is: Watts = Volts × Amps. A device rated 120V × 8.5A draws 1,020W.
Some appliances list a range ("900-1200W") — this is because the motor or heating element cycles. Use the higher number when estimating capacity requirements to avoid running out of power unexpectedly. For devices with motors, also check for a "surge" or "starting watts" figure, which reflects the brief spike on startup.
A cheap kill-a-watt meter (around $20) plugs between any appliance and your outlet and shows real-time wattage. This removes guesswork — your specific refrigerator model matters, since a modern Energy Star fridge pulls 80-100W while an older model might draw 150-200W.
Watt Draw Reference Table
| Appliance | Running Watts | Startup Surge |
|---|---|---|
| Phone charging | 5-18W | None |
| Laptop | 45-65W | None |
| LED TV (50 inch) | 60-100W | None |
| LED room lighting | 10-30W total | None |
| Box fan | 25-75W | None |
| Mini fridge / 12V cooler | 40-60W | 100W |
| Full-size refrigerator | 100-150W | 200W |
| CPAP (no humidifier) | 30-60W | None |
| CPAP (heated humidifier) | 70-120W | None |
| Coffee maker | 800-1,200W | None |
| Microwave | 900-1,500W | None |
| Electric kettle | 1,200-1,500W | None |
| Hair dryer | 1,200-1,875W | None |
| Space heater (small) | 750-1,500W | None |
| Window AC (5,000 BTU) | 500-600W | 1,200-1,800W |
| Power drill | 600-900W | 1,500W |
What a 300Wh Unit Can Power
A 300Wh solar generator is the smallest useful capacity tier. Budget roughly 255Wh of usable energy (300 × 0.85 efficiency).
- Phone charges: 255Wh ÷ 10Wh per charge = ~25 phone charges
- Laptop charges: 255Wh ÷ 50Wh per charge = ~5 full laptop charges
- LED lights (20W): 255 ÷ 20 = ~12.75 hours
- CPAP (45W average): 255 ÷ 45 = ~5.7 hours — one night, no humidifier
- Refrigerator (130W): 255 ÷ 130 = ~2.0 hours — not practical for backup
A 300Wh unit is appropriate for camping where you only need to charge devices, or as a phone/laptop backup during a short outage. It cannot realistically power a refrigerator, microwave, or any heating/cooling appliance.
What a 1,000Wh Unit Can Power
Usable energy: ~850Wh (1,000 × 0.85).
- Refrigerator (130W): 850 ÷ 130 = ~6.5 hours
- CPAP no humidifier (45W): 850 ÷ 45 = ~18.9 hours — two nights comfortable
- CPAP with humidifier (95W): 850 ÷ 95 = ~8.9 hours
- LED TV + lights + fan (150W combined): 850 ÷ 150 = ~5.7 hours
- Laptop (55W): 850 ÷ 55 = ~15.5 hours of use
- Coffee maker (1,000W for 7 minutes): Draws ~117Wh — makes ~7 pots before battery dies
- Microwave (1,100W): 850 ÷ 1,100 = 46 minutes total use time (many 2-3 minute sessions)
- Space heater (1,500W): 850 ÷ 1,500 = ~34 minutes — genuinely not worth attempting
A 1,000Wh unit is the minimum for overnight refrigerator backup during a power outage. For a full 12-16 hour overnight outage with a refrigerator plus a few other loads, plan on needing 1,500-2,000Wh.
What a 2,000Wh Unit Can Power
Usable energy: ~1,700Wh (2,000 × 0.85).
- Refrigerator (130W): 1,700 ÷ 130 = ~13.1 hours
- Refrigerator + lights + fan (195W combined): 1,700 ÷ 195 = ~8.7 hours
- Refrigerator + laptop + phone + lights (300W combined): 1,700 ÷ 300 = ~5.7 hours
- Window AC (550W): 1,700 ÷ 550 = ~3.1 hours
- CPAP (45W): 37+ hours — multiple nights easily
- Multiple device charging (phones, tablets, laptops): days of use
A 2,000Wh unit handles most home backup scenarios for 8-16 hours. It cannot sustain all your home's loads, but it can keep the important things running through a typical overnight outage. For multi-day scenarios, you need solar input or a larger system.
What a Solar Generator Cannot Power (Without Running Out Fast)
Some appliances make a solar generator impractical as a backup regardless of capacity:
Electric water heaters: 4,000-5,500W. A 2,000Wh battery runs an electric water heater for under 30 minutes. This is not a viable backup target.
Central air conditioning: 2,000-5,000W depending on unit size and efficiency. Even a 5,000Wh battery runs a central AC system for under 2 hours. Window units (500-600W) are much more feasible.
Electric clothes dryer: 4,000-6,000W. Not practical on battery power.
Electric range / oven: Individual burners draw 1,200-2,100W each; the oven draws 2,000-5,000W. You can boil water on a single burner briefly, but sustained cooking is impractical.
Continuous space heating: A 1,500W space heater running 4 hours draws 6,000Wh — more than most solar generators hold. If heating is a backup priority, a propane or kerosene heater is the correct tool. A solar generator can supplement with an oil-filled radiator on its lowest setting (400W), which draws 1,700Wh over 4 hours — more feasible with a 2,000Wh+ unit.
The Microwave and Kettle Question
People often ask whether a solar generator can run a microwave or kettle. The answer is yes, but briefly — and only if the unit's output rating is high enough.
A 1,000W microwave run for 3 minutes uses 50Wh. Over an entire 1,000Wh battery, you'd get 17 separate 3-minute microwave sessions before the battery dies. That's actually useful for heating food during an extended outage. The key requirement is that the unit's output rating must exceed the microwave's wattage — a 800W output unit cannot run a 1,000W microwave.
An electric kettle (1,200-1,500W) boils a full kettle in 3-4 minutes, using about 75-100Wh. You'd get 8-11 kettles from a 1,000Wh battery. Again, useful — just make sure your unit's output rating clears the kettle's draw, and that you have a surge rating to handle the startup if applicable.
Our Recommendations
Just phones and laptops: EcoFlow RIVER 2 (~256Wh) — sufficient for a weekend of device charging at under $200.
Refrigerator through the night + devices: EcoFlow DELTA 2 (1,024Wh) or Jackery Explorer 1000 Plus — around $700-800, handles the overnight outage scenario well.
Multi-day essential backup: EcoFlow DELTA 2 Max (2,048Wh) or EcoFlow DELTA Pro — see our best solar generators for home backup guide for a full comparison.
Common Mistakes
- Trying to run heating appliances: Space heaters and electric water heaters are continuous draw devices. No portable solar generator holds enough energy to run them for meaningful durations.
- Ignoring startup surge: Window AC units surge to 1,200-1,800W on startup. Your unit's surge rating must exceed this, even if the running watts are within your output limit.
- Calculating by output rating instead of capacity: A 2,000W output unit can run a 2,000W appliance, but only until the battery dies — often in under an hour if the battery is small. Check both the output and the capacity.
- Running a fully empty battery: LiFePO4 is tolerant of deep discharge, but consistently draining to 0% slightly accelerates degradation. Aim to stay above 10-20% where possible.
Frequently Asked Questions
Can a solar generator run a refrigerator?
Yes. A full-size refrigerator draws 100-150W average, with a startup surge to about 200W. A 1,000Wh solar generator will run a refrigerator for approximately 6-7 hours. A 2,000Wh unit handles about 13 hours. For an overnight outage, plan on needing at least 1,500Wh, or use solar input to supplement draw during the day.
Can a solar generator run a window air conditioner?
Briefly, yes. A 5,000 BTU window AC draws 500-600W running, with a startup surge of 1,200-1,800W. A 2,000Wh unit will run it for approximately 3 hours. The startup surge means you also need a unit with a surge rating above 1,800W — most 2,000W+ output solar generators qualify. For sustained cooling, a gas generator or a solar generator with large expansion batteries is a more practical choice.
How long will a 1000 watt solar generator run a CPAP?
A CPAP without a humidifier draws 30-60W. At 45W average, a 1,000Wh unit provides roughly 1,000 × 0.85 ÷ 45 = 18.9 hours — about two nights of use. With a heated humidifier (70-120W average), expect 7-12 hours, or about one night with margin. Most CPAP users find a 500-800Wh unit sufficient for travel and short outages.
Can a solar generator power a microwave?
Yes, as long as the unit's output rating exceeds the microwave's wattage. A 1,000W microwave run for 3 minutes uses about 50Wh. From a 1,000Wh battery (850Wh usable), you'd get about 17 individual 3-minute sessions. The key requirement is that the solar generator's AC output must be at least 1,000-1,100W — units rated at 800W cannot run standard microwaves.
What size solar generator do I need for camping?
For basic camping with phone charging, LED lights, and a laptop, 300-500Wh is plenty. For camping with a 12V cooler or small portable fridge, 500-800Wh is appropriate. If you want to run a full-size refrigerator, use an electric kettle, or power a CPAP every night, go to 1,000Wh. The EcoFlow RIVER 2 Pro (768Wh) is a popular all-purpose camping choice.
Can a 2000 watt solar generator power a house?
It can power essential loads during an outage — refrigerator, lights, fans, phone and laptop charging, and brief microwave use — for approximately 8-16 hours depending on total draw. It cannot sustain an entire home's electrical load. Central air, electric heating, electric dryer, and electric water heater are all beyond what any portable solar generator handles for more than minutes to an hour.
How do I know if my solar generator can run a specific appliance?
Check two things: the appliance's watt draw (from its label: watts, or volts × amps) against the solar generator's AC output rating (the generator's output must exceed the appliance's draw), and the appliance's surge watts against the generator's surge rating. If both checks pass, the appliance will run. To estimate runtime, use: battery_Wh × 0.85 ÷ appliance_watts = hours.
Can a solar generator run a space heater?
Technically yes, but impractically. A small space heater draws 750-1,500W continuously. A 1,000Wh battery (850Wh usable) running a 1,500W heater lasts about 34 minutes. Even a 2,000Wh battery gives you under 90 minutes of heat. For backup heating, a propane heater rated for indoor use is far more efficient — a small propane canister holds the energy equivalent of several solar generators at a fraction of the weight and cost.
