Power station runtime calculator
Advertising disclosure: This page contains no affiliate links.
Enter your power station's capacity in watt-hours (Wh) and what you're plugging in. The calculator estimates how long it will run, separately for the mains (AC) sockets and the 12 V and USB outputs, and prints the working.
Quick rule: runtime in hours ≈ Wh × 0.81 ÷ watts for the mains sockets, or Wh × 0.855 ÷ watts for 12 V/USB (LiFePO4 battery). Our methodology page explains both factors. Jackery's FAQ uses a single 0.8 factor (Jackery FAQ) and its blog uses 0.85 (Jackery), so results are in the same range. Jackery adds that its formula "is not suitable for devices with variable or high startup power, like air conditioners, refrigerators, or freezers".
Fill in what you know. Results update as you type. Leave advanced settings alone unless you know better figures.
Advanced settings (efficiency, depth of discharge, derate)
Solar recharge (optional)
Your estimate
Estimate only. Real runtime varies. Battery age and temperature, how hard the inverter is working, appliances that cycle on and off, start-up surges and the power station's own standby use all change the result. Always check your appliance's rating plate and your power station's manual, and don't rely on this for medical equipment.
Quick examples (LiFePO4, mains socket, full power)
| Appliance (typical watts, source) | 500 Wh | 1,000 Wh |
|---|---|---|
| Broadband router, 10 W (top of Energy Savers' 7–10 W) | about 40 h | about 81 h |
| Electric blanket, 200 W (top of Energy Savers' 130–200 W) | about 2.0 h | about 4.0 h |
| Laptop charger, 65 W (top of Energy Savers' 20–65 W; check yours) | about 6.2 h | about 12.4 h |
Rounded down. A device with a thermostat or a varying load runs longer than "full power" suggests. Cold or older batteries run shorter.
What will a 1,000 W power station run?
Check whether a "1000" in a name or listing means watt-hours (Wh) or watts (W). They measure different things. The capacity in Wh sets how long things run. The continuous AC output in W is the most it can supply at once. A model number often follows the capacity rather than the output: for example, Jackery states 1,070 Wh capacity and 1,500 W rated AC output for the Explorer 1000 v2 (Jackery UK; Jackery manual). Check both figures on the spec sheet, plus the surge rating if you have anything with a motor or compressor.
What changes the answer
- Battery chemistry: we assume 90% of the rated capacity is usable for LiFePO4 and 80% for NMC.
- AC or DC: the inverter for the mains sockets costs energy (we assume 10%). 12 V and USB outputs cost less (we assume 5%).
- Temperature and age: add a derate in the tool if the battery is cold or old.
- The appliance's real draw: use the rating label, or measure with a plug-in energy meter.
How the calculator works
Every step uses the same formulas, so you can check the result by hand:
AC draw from battery W = AC appliance W ÷ inverter efficiency
DC draw from battery W = DC/USB appliance W ÷ DC conversion efficiency
runtime h = usable Wh ÷ total draw from battery W
(for AC only: runtime h = usable Wh × inverter efficiency ÷ AC load W)
start-up check: running AC W + largest single (start-up W − running W) ≤ inverter surge W
energy for a day = Σ (W × quantity × hours ÷ efficiency)
solar Wh a day = min(panel W, max solar input W) × solar factor × peak sun hours
Manufacturers publish quick versions of this. Jackery's is capacity × 0.85 ÷ device watts (Jackery), and EcoFlow's FAQ uses the same 0.85 (EcoFlow). We split that single factor into depth of discharge and efficiency so you can see and change each one.
Worked example: Evening power cut at home
This is an imaginary 1,000 Wh LiFePO4 power station with a 1,200 W inverter (2,400 W surge), not a real product, running these appliances. The fridge hours are an example of compressor on-time, not a measured figure.
| Appliance | Type | Running | Start-up | Hours/day |
|---|---|---|---|---|
| Fridge (mains) | AC | 120 W | 480 W | 8 h |
| Broadband router | AC | 10 W | – | 6 h |
| LED bulb or lamp | AC | 8 W × 3 | – | 5 h |
| Laptop (mains charger) | AC | 65 W | – | 3 h |
| Phone charging (USB) | DC | 5 W × 2 | – | 2 h |
Solar: 200 W panel lying flat, London in October (1.86 peak sun hours, PVGIS 2014–2023 average).
- Usable energy:
capacity × depth of discharge × (1 − derate)
1,000 Wh × 0.9 × (1 − 0) = 900 Wh - AC load through the inverter:
Σ (running W × quantity) ÷ inverter efficiency
(120 + 10 + 8 × 3 + 65) W = 219 W; 219 ÷ 0.9 = 243.33 W from the battery - DC and USB load:
Σ (running W × quantity) ÷ DC conversion efficiency
(5 × 2) W = 10 W; 10 ÷ 0.95 = 10.53 W from the battery - Runtime with everything on together:
usable Wh ÷ total battery draw W
900 Wh ÷ 253.86 W = 3.55 h (3 h 33 min) - Inverter continuous check:
running AC W ÷ continuous rating W
219 ÷ 1,200 = 18.3% (pass) - Start-up (surge) check:
running AC W + largest single extra start-up W, compared with the surge rating
219 W + 360 W (Fridge (mains): 480 W start-up − 120 W running) = 579 W vs 2,400 W = pass - Energy needed for a day:
Σ (W × quantity × hours ÷ efficiency)
120×8÷0.9 + 10×6÷0.9 + 8×3×5÷0.9 + 65×3÷0.9 + 5×2×2÷0.95 = 1,504.39 Wh from the battery (usable: 900 Wh, 59.8% of a day) - Solar recharge:
min(panel W, max input W) × solar factor = effective W; × peak sun hours = Wh/day; usable Wh ÷ Wh/day = days
200 W × 0.7 = 140 W; × 1.86 h = 260.4 Wh/day; 900 ÷ 260.4 = 3.46 days (6.43 peak-sun hours) from empty to full
Result: about 3 h 33 min with everything on at once. Continuous check Pass Start-up check Pass One day's use needs 1,504 Wh from the battery against 900 Wh usable, so a full charge covers about 60% of the day. The panel would take about 3.5 October days to refill it from empty.
| Appliance | Runtime alone |
|---|---|
| Fridge (mains) | 6 h 45 min |
| Broadband router | 81 h (about 3.4 days) |
| LED bulb or lamp | 33 h 45 min |
| Laptop (mains charger) | 12 h 28 min |
| Phone charging (USB) | 85 h 30 min (about 3.6 days) |
Default assumptions and where they come from
All defaults live in one data file, with a source or reason for each. Where we couldn't find a published figure we say it's a rough estimate.
| Setting | Default | Why |
|---|---|---|
| Inverter efficiency (AC) | 90% | Rough estimate. EcoFlow's worked examples use 90% inverter efficiency as a planning assumption. Jackery and EcoFlow's quick formulas use a single 0.85 factor (Jackery's newer FAQ 0.8) covering all losses. 90% here combined with the 90% LiFePO4 usable depth of discharge gives an overall factor of 0.81, between those two quick-formula factors. It is not a measured figure for any product. [1] [2] [3] [4] |
| DC/USB conversion efficiency | 95% | Rough estimate. DC and USB outputs skip the inverter but still pass through a voltage converter, so we assume a smaller loss than AC. 95% is our planning estimate, not a published figure. Adjust it if your manufacturer gives one. |
| Usable depth of discharge, LiFePO4 | 90% | Rough estimate. EcoFlow's depth-of-discharge article gives 70–90% for lithium-ion and LiFePO4 batteries, with 80% recommended for its LiFePO4 DELTA Pro. Its 100Ah worked example uses 100% for LiFePO4, and Dometic says lithium iron phosphate batteries are "nearly 100%" usable. BLUETTI's Elite 100 V2 manual uses 90% in its operation-time formula ("DoD (Depth of Discharge) is 90%"). We use 90%, a planning estimate within that spread. It's at the top of EcoFlow's 70–90% range, so it isn't a cautious figure: lower it if you want more margin. [1] [2] [3] [4] |
| Usable depth of discharge, NMC lithium-ion | 80% | EcoFlow gives a recommended depth of discharge of up to 80% for (non-LiFePO4) lithium-ion batteries. [1] [2] |
| Temperature and ageing derate | 0% | Rough estimate. Off by default. EcoFlow says there is no fixed winter penalty and treats cold and age as planning factors (its example uses 0.95 for age and 0.90 for cold). Add a derate if the battery is old or cold. [1] [2] |
| Solar factor (share of panel rating delivered) | 70% | Rough estimate. Panels rarely deliver their rated watts: Jackery lists light intensity, angle, temperature, cables and charge-controller conversion as causes. 70% of rated watts at peak-sun equivalent is our planning estimate; Jackery does not publish a single figure. [1] |
| Inverter headroom warning | above 80% of continuous rating | Rough estimate. We show a warning (not a fail) when running AC load is above 80% of the continuous rating, to leave headroom for loads that vary. A cautious rule of thumb, not a manufacturer requirement. |
| Start-up check method | running W + largest single extra start-up | Peak demand = all running watts + the single largest extra start-up watts (start-up W − running W), because appliances rarely start at the same moment. If several motor loads may start together, add their start-ups yourself. [1] [2] [3] |
| Car-style 12 V socket limit | 10 A (about 120–126 W) | The car-style 12 V socket on each of the four power stations we checked (one per major brand) is rated 10 A: 12 V × 10 A = 120 W (EcoFlow states 12.6 V, 126 W). This is what those four spec sheets say, not a rule for every model: check yours. USB-C ports have their own limits: check each port's rating on the maker's spec sheet. [1] [2] [3] [4] |
| Safety margin (sizing calculator) | 20% on top of the energy you need | Rough estimate. Sizing adds 20% on top of the energy you need, to allow for battery ageing, cold, appliances that draw more than expected and the power station's own standby use (BLUETTI's runtime formula adds the unit's self-consumption, about 10 W for the Elite 100 V2). 20% is our planning choice, not a published figure. [1] |
| Days without recharging (sizing calculator) | 1 day | Rough estimate. One day without recharging unless you change it. |
Typical appliance wattages (check your own label)
These are typical ranges from published sources, not measurements of your appliance. The calculator fills in the upper end of each range so the estimate errs on the cautious side. Your appliance's rating plate, charger or manual is always the better figure.
| Appliance | Type | Typical | Notes and source |
|---|---|---|---|
| Fridge (mains) | AC | 40–120 W; start-up about 480 W (4 × running) | Pre-filled with the upper end of the typical range (cautious for runtime and inverter checks). Fridges switch on and off, so they don't draw this all day. For daily energy, use the kWh/year on the energy label: average watts = kWh/year × 1,000 ÷ 8,760, run for 24 hours. Start-up pre-filled at 4 × running watts: BLUETTI's manual says motors and compressors may start at 2–4 times rated power (EcoFlow says 2–3 times), so we use the cautious end. A US generator guide (Honda) estimates about 1,200 W starting for a fridge or freezer. Check your fridge's manual if it lists a start-up figure. Source · start-up source · EcoFlow blog · Honda Power Equipment (US) generator wattage estimation guide |
| Fridge-freezer (mains) | AC | 200–400 W; start-up about 1,600 W (4 × running) | Pre-filled with the upper end of the typical range (cautious for runtime and inverter checks). Cycles on and off like a fridge; see the energy label tip for daily energy. Start-up pre-filled at 4 × running watts: BLUETTI's manual says motors and compressors may start at 2–4 times rated power (EcoFlow says 2–3 times), so we use the cautious end. A US generator guide (Honda) estimates about 1,200 W starting for a fridge or freezer. Check your fridge's manual if it lists a start-up figure. Source · start-up source · EcoFlow blog · Honda Power Equipment (US) generator wattage estimation guide |
| 12 V compressor cool box | DC/USB | about 9.12 W | One manufacturer's figure for one model (Dometic CFX5 45: 0.76 Ah/h × 12 V ≈ 9.12 W) at 32 °C ambient with 4 °C inside. Your model and conditions will differ; this is already an average, so use 24 hours. Source |
| Laptop (mains charger) | AC | 20–65 W | Pre-filled with the upper end of the typical range (cautious for runtime and inverter checks). Check the watts printed on your charger. Many laptops can also charge from USB-C (DC), which avoids inverter losses. Source |
| Phone charging (USB) | DC/USB | 2.5–5 W | Pre-filled with the upper end of the typical range (cautious for runtime and inverter checks). Fast chargers can draw more while charging quickly. Source |
| Tablet charging (USB) | DC/USB | 10 W | Energy Savers lists 10 W. Source |
| Broadband router | AC | 7–10 W | Pre-filled with the upper end of the typical range (cautious for runtime and inverter checks). In a power cut your broadband may still be down if the street cabinet has no power. Source |
| LED bulb or lamp | AC | 4.3–13 W | Philips CorePro A60 bulbs (Signify UK product data): 4.3 W (470 lm, like an old 40 W bulb), 8 W (806 lm, like 60 W), 13 W (1,521 lm, like 100 W). Pre-filled with the upper end. The watts are printed on your bulb. Source · source 2 · source 3 |
| LCD TV | AC | 125–200 W | Pre-filled with the upper end of the typical range (cautious for runtime and inverter checks). Newer, smaller TVs often use less; check the label or the energy label. Source |
| Electric blanket | AC | 130–200 W | Pre-filled with the upper end of the typical range (cautious for runtime and inverter checks). Most have lower settings that use less. Source |
| CPAP machine (ResMed AirSense 11) | AC | 56.1–73.2 W | ResMed's own user guide gives typical 56.1 W and peak 73.2 W for the AirSense 11. Heated tubing and humidifier settings change it. If you rely on a medical device, ask your supplier about backup power; don't rely on this estimate. Source |
| Diesel heater (12 V) | DC/USB | 14–29 W | Pre-filled with the upper end of the typical range (cautious for runtime and inverter checks). One model's published running range (Webasto Air Top 2000 STC). The glow plug draws more for a short time at start-up and shut-down; check your heater's manual. Source |
| Starlink (Standard kit) | AC | 75–100 W | Pre-filled with the upper end of the typical range (cautious for runtime and inverter checks). Starlink's published average for the Standard kit. Other kits differ. Source |
| Desktop computer | AC | 80–200 W | Pre-filled with the upper end of the typical range (cautious for runtime and inverter checks). Source |
| Microwave | AC | 600–1,500 W | Pre-filled with the upper end of the typical range (cautious for runtime and inverter checks). The watts on the front are usually cooking power; the power drawn from the socket is higher (Honda's guide lists about 1,000 W for a 650 W microwave). Check the rating plate. Source |
| Kettle | AC | 3,000 W | Most UK kettles are 2,000–3,000 W, more than many portable power stations' continuous rating. Check the rating plate. Source |
| Hairdryer | AC | 2,000 W | High-power heater: check the rating plate. Source |
Where to find your power station's figures
You need three numbers from the spec sheet: capacity in Wh, continuous (rated) AC output in W, and surge or peak output in W. They're usually on the manufacturer's product page or in the manual, for example at EcoFlow UK, Jackery UK, BLUETTI UK or Anker SOLIX UK. We haven't tested any of these, and listing them isn't a recommendation.
Frequently asked questions
How long will a power station last?
Divide the usable energy by what you're running: capacity (Wh) × 0.81 ÷ watts for mains devices. For example, 1,000 Wh running 200 W lasts about 4 hours.
How long will a Jackery last?
Use the Wh on your model's spec page in the formula above. Jackery's own estimate is Wh × 0.8 ÷ watts (Jackery FAQ).
Can I run a TV or laptop?
Check the watts on the device's rating label against the power station's continuous AC output. If it's within the rating, enter the watts in the tool to see how long.
Why does the calculator show a lower figure than the maker's runtime claims?
We use cautious planning assumptions and full-power draw. Makers may base their examples on different factors. We show our working so you can compare.
Why is my real runtime shorter than the estimate?
Common reasons are a cold or older battery, the inverter's own standby use, appliances that draw more than their label at times, and start-up surges. Add a derate in the advanced settings to plan for this.
Why does the calculator say my fridge needs more than its running watts?
Fridge and freezer compressors need a short burst of extra power to start. BLUETTI's manual says motors and compressors may start at 2–4 times their rated power, and EcoFlow says 2–3 times; a US generator guide (Honda) estimates about 1,200 W starting for a fridge or freezer. The inverter's surge rating has to cover that burst on top of everything else that's running.
Should I use AC or the 12 V and USB ports?
If an appliance can run from DC or USB, it usually avoids inverter losses, so the battery lasts longer. Check the port's limit: the car-style 12 V socket on each of the four power stations we checked is rated 10 A, about 120 W (EcoFlow RIVER 3: 12.6 V, 10 A, 126 W, Jackery Explorer 1000 v2 (manual: Car Port 12V⎓10A), BLUETTI AC180, Anker SOLIX C1000). Other models can differ, so check your spec sheet.
How do I work out a fridge's daily energy?
Use the energy label: average watts = kWh per year × 1,000 ÷ 8,760. Enter that as running watts with 24 hours a day, and enter the start-up watts separately for the surge check.
Related: What size do I need? · Spec table · Power station safety
Sources
- Jackery blog: What can a Jackery Explorer 1000 Plus run? (formula: capacity in Wh × 0.85 ÷ operating wattage, "calculated considering 85% efficiency")
- Jackery FAQ: How can I estimate the runtime of my portable power station? (formula: Wh × 0.8 ÷ device W; not suitable for fridges and other start-up loads)
- EcoFlow Ireland FAQ: How do I estimate runtime? (Wh × 0.85 ÷ device W)
- EcoFlow blog: How long does a 100Ah lithium battery last? (DoD, 90% inverter efficiency example)
- EcoFlow blog: What is depth of discharge for batteries? (lithium-ion up to 80%; DELTA Pro LiFePO4 recommended 80%)
- EcoFlow blog: How to estimate DELTA Pro Ultra X runtime (SOC window × remaining capacity × temperature × efficiency; 0.90 planning assumptions)
- EcoFlow blog: Do portable power stations work in cold weather? (usable capacity factor; no fixed winter penalty)
- Jackery: Charging power loss (why panels deliver less than their rated watts)
- European Commission JRC, PVGIS monthly radiation (MRcalc), PVGIS-SARAH3, 2014–2023; daily values calculated by us from monthly totals
- Energy Savers (Centre for Sustainable Energy): How much electricity am I using? (typical power ratings and ranges)
- Centre for Sustainable Energy: How much electricity am I using? (average power ratings)
- Honda Power Equipment (US) generator wattage estimation guide: approximate starting and running watts (US generator guide estimate)
- Home generator systems wattage worksheet, archived copy (Wayback Machine, 8 Sep 2024): total running watts + the single highest additional surge ("you will only need to factor in the appliance with the highest additional surge watts")
- Webasto Air Top 2000 STC specifications (power consumption 14–29 W)
- Starlink Standard kit specification sheet (average power consumption 75–100 W)
- Energy Saving Trust: energy saving light bulbs (lumens, not watts, measure brightness)
- ResMed AirSense 11 user guide (ResMed, official PDF), technical specifications: typical power consumption 56.1 W, peak 73.2 W
- Signify (Philips) CorePro LEDbulb 4.3-40W A60 E27, UK product data: 470 lm, power consumption 4.3 W
- Signify (Philips) CorePro LEDbulb 8-60W A60 E27, UK product data: 806 lm, power consumption 8 W
- Signify (Philips) CorePro LEDbulb 13-100W A60 E27, UK product data: 1,521 lm, power consumption 13 W
- BLUETTI Elite 100 V2 user manual (EU), FAQ: operation time uses "DoD (Depth of Discharge) is 90%" and inverter efficiency "over 90%"; devices with motors or compressors may start at 2–4 times their rated power; operation time includes self-consumption of about 10 W; specifications: Cigarette Lighter Port 12V / 10A
- EcoFlow blog: How many watts does a refrigerator use? (start-up surge typically 2–3 times running watts)
- EcoFlow UK: RIVER 3 specs, Car Output 12.6V, 10A, 126W max (checked 18 Oct 2026)
- Jackery Explorer 1000 v2 user manual (230 V version), Car Port 12V⎓10A (checked 18 Oct 2026)
- Anker SOLIX UK: C1000 specs, Car Auxiliary 1× 12V⎓10A (checked 18 Oct 2026)
- Dometic UK: CFX5 45, Energy Consumption 12VDC (Ambient@32C, Internal@4C) 0.76 Ah/h (checked 18 Oct 2026)
- Dometic CFX3 45 product FAQ (usable capacity: lithium NMC "roughly 80%", lithium iron phosphate "nearly 100%")
- BLUETTI UK: AC180 product page (12V DC Outlet: "1 × 12V/10A (Car outlet, regulated.)")
- Jackery UK: Explorer 1000 v2 product page
Figures last checked: 18 October 2026.