If you’re planning a weekend off-grid or a power outage, you can do so with confidence once you understand how long your solar power generator can run. The runtime of your power-critical devices is dependent upon battery capacity, appliance wattage, and appliance conversion losses. This guide will help you understand runtime calculations, compare common appliance requirements, and select appropriate capacity. You’ll also discover how solar recharging can help to increase the runtime and how to prevent common sizing mistakes.
What determines how long a solar generator will last?
Watts vs. watt-hours
Watts and watt-hours can help you determine the runtime of your solar generator. Watts (W) are a measure of the rate at which an appliance uses electricity, while watt-hours (Wh) are a measure of stored energy. Imagine watts to be speed and watt-hours to be the size of the fuel tank. Generally, the higher the watts, the more battery life the appliance uses, and both measurements are important for determining the length of time the battery will last.
Battery capacity vs. AC output power
Whether a solar generator can power an appliance and how long it will last depends on the capacity of the battery and the amount of power the appliance consumes. Capacity, in watt-hours, represents the amount of energy that can be stored. The output power is measured in watts and is known as the rated AC output. A larger battery will not power appliances that require more power than its output. So, make sure to look at both specs when selecting a solar generator.
How a solar generator supplies energy
A solar generator is a mobile power station that has solar panels that create electrical power. The panels convert sunlight into electrical energy, which in turn is used to charge the battery. The inverter changes the direct current (DC) energy stored in the batteries to alternating current (AC) for compatible appliances. The runtime depends on the battery size, loads, losses in the converter, and the amount of available sunlight. For noise level and operating characteristics for each model, consult the manufacturer’s specifications.
How to calculate solar generator runtime
Find your appliance’s power consumption.
Check the power use of your appliance on its rating label, instruction manual, or plug-in wattmeter. This data will enable you to calculate how much time a solar generator will provide power for your equipment. If the appliance is motor-operated (such as refrigerators), look at the watts used when the appliance is running, and the surge watts needed during start-up. Motors usually need more power when starting up, which can impact compatibility with your generator.
Check usable battery capacity and output limits.
Next, look at the wattage (W) and watt-hour (Wh) battery rating on your solar generator. Always check the manufacturer’s official UK product page for correct specifications. The battery capacity is a measure of how much energy is stored, while the output rating defines how many appliances you can run at once. Make sure that the total running load does not exceed the generator’s rated AC output.
Apply the runtime formula.
Use this formula to estimate runtime:
Runtime (hours) = Capacity (Wh) × 0.85 ÷ Appliance power (W)
The 0.85 factor is an assumed estimate, not a manufacturer-specified figure. It allows for roughly 15% of stored energy being lost to inverter conversion and other system losses. Actual efficiency varies with model, load, and conditions, so treat results as estimates. For example, a 60W laptop running on a 1,070Wh unit lasts approximately 15.2 hours (1,070 × 0.85 ÷ 60). Very hot or cold weather can impact performance.
How long can a power station run common appliances?
A portable power station’s runtime depends on its battery capacity and the wattage of your appliances. A larger battery generally keeps your devices running longer, whilst higher power consumption reduces available runtime.
The table below provides theoretical runtime estimates across four battery capacities. It assumes 85% usable capacity (a 15% allowance for conversion and system losses) and continuous power draw. Microwave and kettle figures demonstrate the calculation method using their stated input wattages, not the number of heating cycles users can expect. Actual runtimes vary with usage patterns and appliance behavior. Fridge-freezers cycle on and off, often running longer than continuous-load estimates suggest. Your power station’s AC output rating must also support both the appliance’s running wattage and startup surge.
| Table 1 | ||||
| Appliance (illustrative load) | 500Wh | 1,000Wh (1kWh) | 2,000Wh (2kWh) | 3,000Wh (3kWh) |
| Wi-Fi router (10W) | ≈ 42.5 h | ≈ 85.0 h | ≈ 170 h | ≈ 255 h |
| LED lighting, four bulbs (40W) | ≈ 10.6 h | ≈ 21.3 h | ≈ 42.5 h | ≈ 63.8 h |
| Phone/tablet charging (20W) | ≈ 21.3 h | ≈ 42.5 h | ≈ 85.0 h | ≈ 128 h |
| Laptop (60W) | ≈ 7.1 h | ≈ 14.2 h | ≈ 28.3 h | ≈ 42.5 h |
| 32″ LED TV (50W) | ≈ 8.5 h | ≈ 17.0 h | ≈ 34.0 h | ≈ 51.0 h |
| Fridge-freezer (200W running, continuous) | ≈ 2.1 h | ≈ 4.3 h | ≈ 8.5 h | ≈ 12.8 h |
| Microwave (800W input, illustrative) | ≈ 0.5 h | ≈ 1.1 h | ≈ 2.1 h | ≈ 3.2 h |
| Electric kettle (1,800W, illustrative) | ≈ 0.2 h | ≈ 0.5 h | ≈ 0.9 h | ≈ 1.4 h |
Your power station’s runtime depends on its battery capacity and the wattage of connected appliances. Doubling capacity doubles runtime, whilst higher wattage reduces operating hours. Calculate each appliance’s energy use by multiplying its wattage by its expected operating hours, then add the results. Allow for system losses and a reserve. Check that the power station supports the combined running wattage of devices used simultaneously, as well as any startup surge.
How to choose the right solar generator capacity
Calculate total energy requirements
First, make a list of all the appliances you would like to power and how many hours they are likely to operate each day. Add up all the watt-hours (Wh) by multiplying the wattage of each appliance by the number of hours it is used each day. Next, divide the total by 0.85 to allow for an assumed 15% conversion loss. Finally, multiply by 1.2 to add a 20% safety margin. This margin is an assumed buffer for unforeseen energy needs, and you can adjust it to suit your own situation.
Check running watts and startup surge
Battery capacity determines how long a solar generator will last, while the rated AC output dictates which appliances can be run at the same time. Add up the running watts of all the appliances you will use concurrently and compare the total with your model’s rated AC output, listed on its official UK product page. Refrigerators and other motor-driven appliances need extra power to start, so check the startup surge in the appliance’s specifications or manual and confirm your power station can handle it before buying.
Compare different capacity options
Solar generators come in many sizes, so be sure the watt-hours you have can meet your home’s energy requirements—smaller units for phones, lights, laptops, and larger units for refrigerators and several appliances. Consider usable capacity, rated output, charging capabilities, and expansion capabilities to determine the system you require.
Choose based on your backup duration and usage
The selection of the appropriate power station will be based on the desired backup power time and the amount of power that is required. The shorter the outages, the smaller the batteries needed, and the longer the outages (overnight or multi-day off-grid), the larger the batteries needed.
For instance, a fridge-freezer, Wi-Fi router, and four LED bulbs draw around 250W if the fridge runs continuously (200W + 10W + 40W). That would need about 2,000Wh (before losses) over 8 hours, more than the 500 v2 (512Wh) or the 1000 v2 (1,070Wh) can supply. In practice, a fridge cycles on and off. Using the average-consumption estimate in Table 2, the requirement falls to approximately 823Wh (including the assumed 15% conversion loss and 20% margin). The 1000 v2’s 1,070Wh battery may meet that figure under these assumptions, while the 500 v2’s 512Wh falls short and larger models offer more headroom. Actual refrigerator consumption and startup surge must also be checked, so determine fridge surge requirements and measure consumption for correct sizing.
| Table 2 | ||
| Item | Calculation | Energy |
| Fridge-freezer (assumed 200 kWh/year energy label; replace with the reader’s own) | 200,000 Wh ÷ 365 = 548 Wh/day; × 8/24 | ≈ 183 Wh |
| Wi-Fi router | 10W × 8 h | 80 Wh |
| LED lighting | 40W × 8 h | 320 Wh |
| Total at the appliances | ≈ 583 Wh | |
| After conversion losses | 583 ÷ 0.85 | ≈ 686 Wh |
| With 20% margin | 686 × 1.2 | ≈ 823 Wh |
Table 1 assumes a refrigerator draws a continuous 200W load, while the 200kWh/year example in Table 2 estimates average consumption over a full year. These represent different operating scenarios and should not be treated as equivalent. Use annual energy ratings as a baseline, but calculate actual consumption based on operating conditions before choosing a suitable power station.
How can solar recharging extend runtime?
Solar recharging may extend your power station’s runtime, but it will not necessarily maintain the battery level during use. The result depends on sunlight conditions, panel input, charging limits, and appliance power consumption. Supported Jackery Explorer v2 models can recharge through SolarSaga panels, a wall outlet (AC adapter), or a 12V car adapter, and the Explorer 240 v2 also supports USB-C PD charging. Solar charging time drops as you add panels. For example, the Explorer 1000 v2 takes 15 hours with one panel and 3 hours with six, while the Explorer 240 v2 takes 11 hours with one panel. Pass-through charging is not specified for every model. Before purchasing, check your model’s UK product page or manual to confirm whether it is supported, along with compatible SolarSaga panels and supported charging configurations.
Common mistakes when estimating runtime
- Confusing Watts With Watt-Hours: Watts measure power consumption, whilst watt-hours measure energy capacity. Confusing these units can produce unrealistic runtime estimates for your appliances.
- Ignoring Startup Surge: Motor-driven appliances often require extra power when starting. Check their startup surge requirements to ensure your power station can handle these temporary demands.
- Forgetting Conversion Losses: Inverters and internal components consume energy during operation. Account for these losses because usable battery capacity is lower than its rated capacity.
- Misjudging Cycling Appliances: Refrigerators and air conditioners switch on and off automatically. Their actual runtime depends on duty cycles, ambient temperatures, and cooling demands.
- Overlooking Operating Temperature: Battery performance varies with temperature during charging, discharging, and storage. Check your model’s specified temperature ranges to avoid inaccurate estimates and potential operating issues.
- Choosing Insufficient Capacity: Selecting a power station that barely meets your calculated requirements leaves little flexibility. Allow extra capacity for unexpected loads, efficiency losses, and changing power demands.
Conclusion
The first step to picking the right solar generator is to know the energy consumption, run time, and power level of the appliances. Before buying, determine the total watt-hours, conversion losses, inverter output, and start-up surge. Allow for additional storage for unforeseen circumstances and extended power failures. View the Jackery Solar Generator collection and compare relevant models to decide the best fit for your setup, or reach out to Jackery with the appliance information for advice on choosing a power station that fits your backup needs.
FAQs
Can a solar generator run a fridge all night?
Yes, a solar generator can power a refrigerator overnight if it has sufficient usable battery capacity. Actual runtime depends on energy consumption, efficiency, and compressor cycling. Check the appliance’s energy label or measure its consumption. A 1,000–2,000Wh unit may work, but results vary. Ensure the inverter can handle the compressor’s startup surge, which can be several times the running wattage. Check the appliance’s manual or label for the exact figure.
What size solar generator do I need for a power cut?
Choose capacity and output depending on the appliances required and the duration of the power outage. For electronics, lights, and routers, 500- 1,000 Wh is a good choice. If you need to refrigerate and have longer backup times, 1,500–3,000Wh is a good choice. The Jackery Explorer 500 v2 is suitable for simple emergencies. When purchasing, determine running watts, start-up surges, and watts per day.
Can I use a solar generator while it charges?
Pass-through charging, which powers appliances while the unit receives energy from solar panels or a wall outlet, varies by model. Check your model’s manual or UK product page to confirm it is supported. If it is, and incoming power exceeds consumption, the battery continues charging. Otherwise, stored energy decreases more slowly. Maintain ventilation, and never exceed the inverter output limits during simultaneous charging and usage.
What is better, an inverter or solar generator?
A solar generator is an all-in-one portable unit that includes a battery, inverter, and charge controller. You can explore Jackery models that work well for camping, traveling, and as a basic emergency backup power supply. Fixed solar inverters can be used for larger household loads by using separate batteries and solar panels.
