Portable Power Station Runtime Calculator
Calculate how long a portable power station will run your appliances during a power outage. Estimate runtime, compare station sizes, and plan backup power for camping, emergencies, and off-grid use.
Appliance Loads
Backup Settings
How long you need backup power during the outage.
12V for small portable setups, 24V for mid-size, 48V for whole-home.
LiFePO4 recommended: safest, longest life, deepest discharge.
Auto-set by chemistry. LiFePO4: 80%, Lead-Acid: 50%.
Modern pure sine wave inverters: 90–95%. Use 90% for conservative sizing.
Extra capacity buffer for temperature, aging, and unexpected loads.
Total wattage of solar panels connected to charge controller.
Average daily peak sun hours for your location.
MPPT controllers: 95–98%. PWM controllers: 80–90%.
Backup System Results
Suggested Battery Configurations
Solar Recharge Estimate
Planning Notes
Common portable power station loads pre-loaded. Add your actual devices to see accurate runtime.
Mathematical Formulas
For portable power stations, Battery Voltage and DoD are internal — compare the Energy Required to the station's usable Wh rating.
Formulas & Worked Examples
Example 1: Phone Charging & Small Devices
Charge two phones and run a Wi-Fi router for an evening power outage (6 hours).
Given Values
- Phone Chargers ×2: 15W each = 30W total
- Wi-Fi Router: 12W
- Backup Duration: 6 hours
Step 1: Total running load
= 42W
Step 2: Energy for 6 hours
= 252 Wh
Step 3: After inverter efficiency (85%)
= 296 Wh
Step 4: With 20% safety margin
= 356 Wh
Final Answer
A 400Wh portable power station provides ample capacity for phone charging and Wi-Fi through a 6-hour evening outage.
Small device loads are easy to back up — even compact power stations handle them comfortably.
Example 2: Laptop Work Setup
Keep a laptop and desk lamp running during a daytime work outage (4 hours).
Given Values
- Laptop: 60W
- LED Desk Lamp: 10W
- Backup Duration: 4 hours
Step 1: Total running load
= 70W
Step 2: Energy for 4 hours
= 280 Wh
Step 3: After inverter efficiency (85%)
= 329 Wh
Step 4: With 20% safety margin
= 395 Wh
Final Answer
A 400–500Wh portable power station covers a laptop work setup for a half-day outage.
Laptops are moderate loads — plan for at least 400Wh to leave headroom for battery degradation.
Example 3: Camping Lights & Fan
Power LED string lights and a small fan while camping overnight (10 hours).
Given Values
- LED String Lights ×2: 10W each = 20W total
- Portable Fan: 50W
- Backup Duration: 10 hours
Step 1: Total running load
= 70W
Step 2: Energy for 10 hours
= 700 Wh
Step 3: After inverter efficiency (85%)
= 824 Wh
Step 4: With 20% safety margin
= 988 Wh
Final Answer
A 1,000Wh portable power station comfortably runs lights and a fan through a full camping night.
Overnight loads add up — a 1,000Wh station is the sweet spot for camping comfort.
Portable Power Station Energy Flow
Energy flows from the internal DC battery through the inverter to your AC appliances, with losses at each conversion step.
Portable Power Station Capacity Comparison
| Station Capacity | Usable Wh (85% eff.) | Fridge Runtime | Phone Charges | Laptop Runtime | Best For |
|---|---|---|---|---|---|
| 250 Wh | 213 Wh | 1–2 h | ~14 | ~3.5 h | Phone & device charging |
| 500 Wh | 425 Wh | 2–3 h | ~28 | ~7 h | Small device + lights |
| 1,000 Wh | 850 Wh | 5–6 h | ~56 | ~14 h | Fridge + devices overnight |
| 1,500 Wh | 1,275 Wh | 8–10 h | ~85 | ~21 h | Fridge + lights + Wi-Fi |
| 2,000 Wh | 1,700 Wh | 10–12 h | ~113 | ~28 h | Full essential load 12h |
| 2,500 Wh | 2,125 Wh | 13–15 h | ~142 | ~35 h | Extended outage backup |
Runtimes assume standard refrigerator cycling (30–50% duty cycle). Phone charges based on 15Wh per charge. Laptop runtime at 60W continuous.
Frequently Asked Questions
How long will a portable power station run a refrigerator?
A 1,000Wh lithium portable power station runs a standard refrigerator (150W running) for approximately 5–6 hours. A 2,000Wh station extends this to 10–12 hours. Remember the compressor cycles on and off, so actual runtime may be longer.
What size portable power station do I need?
For essential loads (fridge + Wi-Fi + lights + phone charging, ~250W average), a 1,000Wh station provides 3–4 hours. For overnight backup (8 hours), plan for 2,000–3,000Wh. For multi-day outages, consider 3,000Wh+ with solar recharging.
Can a portable power station run a microwave or space heater?
Most portable power stations (1,000–2,000W output) cannot run microwaves (1,000–1,500W) or space heaters (1,500W+) simultaneously with other loads. They may handle a microwave alone briefly, but not continuously.
Do portable power stations lose charge when not in use?
Yes, all lithium batteries self-discharge at 1–5% per month. Store portable power stations at 50–80% charge in a cool location. Check charge every 3 months if in long-term storage.
What Is Portable Power Station Runtime?
Why This Calculation Matters
→ Portable power stations are rated in Wh (watt-hours), but real runtime depends on your specific appliances — a station rated for '2,000Wh' doesn't mean 2,000W for 1 hour.
→ Inverter efficiency losses (10–15%) reduce usable capacity. A 1,000Wh station provides roughly 850–900Wh of actual output.
→ Lithium NMC batteries should not be discharged below 80–90% depth of discharge. LiFePO4 units allow 80–100% DoD.
→ Higher discharge rates reduce usable capacity — running a 1,500W load from a 1,000Wh station depletes it faster than running 500W.
→ Matching your load to a power station's output rating is critical — exceeding continuous output shuts down the unit, even if capacity remains.
Practical Applications
Power Outage Preparedness
Before buying a portable power station, calculate exactly how long it will power your critical appliances during an outage.
Camping & RV Trips
Plan your portable power station capacity based on what you'll actually plug in — fridge, lights, phone charging, CPAP.
Worksite & Remote Power
Power tools, lighting, and equipment at remote locations without grid access.
Emergency Kit Planning
Determine what size portable power station fits your household's critical emergency load requirements.
Common Mistakes to Avoid
✗ Comparing Wh capacity across different battery chemistries — NMC stations at 80% DoD deliver less usable energy than LFP stations rated at the same Wh.
✗ Ignoring inverter efficiency losses — a 1,000Wh station provides only 850–900Wh of usable AC energy after DC-to-AC conversion.
✗ Exceeding the continuous output rating — running a 1,800W load on a 1,500W-rated station shuts it down even though it's below surge capacity.
✗ Assuming manufacturer Wh ratings include DoD limits — some manufacturers quote DC capacity which excludes both inverter losses and DoD derating.
✗ Forgetting that high discharge rates reduce usable capacity — a 1,000Wh station powering 1,000W drains faster than one powering 250W.
✗ Not checking surge rating for motor-driven appliances — refrigerators and pumps need 3–4× running wattage during startup.
✗ Storing a portable power station fully charged for months — lithium batteries self-discharge 1–5% per month; store at 50–80% for long-term storage.
✗ Ignoring temperature effects on runtime — cold weather below 0°C reduces lithium capacity by 10–25%.
Why Trust These Calculations?
This calculator uses standard electrical engineering formulas. Runtime estimates assume 85% inverter efficiency and standard depth-of-discharge limits.
View our methodology →Home Power Outage Battery Backup Calculator
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