Solar Generator Calculator

Find the right portable power station size. Check off your devices, set how long you need power, and pick your solar panel — get your Wh capacity recommendation instantly.

How to Use This Calculator

Check off your devices

Select every device you need to run or charge. Each device shows its wattage, daily hours of use, and daily watt-hour consumption. The list covers the most common portable power station use cases — camping gear, work-from-anywhere setups, emergency backup, and outdoor events. Note that high-wattage appliances like coffee makers and microwaves consume a large portion of the budget despite short daily use.

Set days of use

How many days between full recharges? For a weekend camping trip with no solar: 2 days. For a week-long overlanding trip with a solar panel: 7 days (but the solar will recharge daily, so the battery just needs to bridge the nights). The calculator applies a 20% headroom above your raw consumption — accounting for inverter inefficiency (typically 85-90%) and battery aging over time.

Select your solar recharge panel

If you'll be recharging via solar while in the field, select your panel wattage. The calculator shows how many days it takes to fully recharge the station from empty, and whether your panel produces enough to sustain your load indefinitely (daily solar production ≥ daily consumption). If your solar covers daily use, you only need enough battery capacity to bridge through nights and cloudy hours — not multiple days of storage.

The Formula

Daily Wh = Sum of (device watts × hours per day) Total Wh needed = Daily Wh × Days of use Recommended capacity = Total Wh × 1.20 (20% headroom) Standard size = Next available power station size above recommended Daily solar harvest = Panel watts × 5 peak sun hours × 0.85 efficiency Recharge time (days) = Station capacity ÷ daily solar harvest Can sustain = Daily solar harvest ≥ Daily Wh consumption

Power Station Size Guide

256–500 WhPhone, laptop, lights for 1-2 days. Day hikes, short trips.

700–1,000 WhLaptop + CPAP + lights for 2-3 days. Weekend camping.

1,500–2,000 WhMini fridge + devices + fan. Car camping, tailgating, emergency backup.

2,400–3,000 WhHome essentials during power outage (fridge, lights, devices, fan).

4,000–5,000 WhExtended outage backup, refrigerator + medical devices + work setup.

Example

Weekend camping + work setup — 2 days

A remote worker takes a 2-day camping trip and needs to work from the campsite. Devices: laptop (65W × 6h = 390Wh), phone charging (20W × 2h = 40Wh), LED lights (20W × 4h = 80Wh), CPAP (40W × 8h = 320Wh). Daily total: 830Wh.

Daily consumption830 Wh

2 days total1,660 Wh

With 20% headroom1,992 Wh

Recommended station2,000 Wh (e.g., EcoFlow Delta 2)

With 200W solar panel200 × 5 × 0.85 = 850 Wh/day solar production

Sustainable?Yes — 850Wh solar > 830Wh daily load

A 2,000 Wh power station with a 200W folding solar panel handles this setup indefinitely. The station bridges overnight consumption; the panel fully recharges it the next day while also powering daytime loads. This exact setup — EcoFlow Delta 2 + 220W panel — is a popular choice among remote workers.

FAQ

What is a solar generator (portable power station)? ▼

A solar generator (also called a portable power station or solar power station) is a self-contained unit combining a lithium battery, pure sine wave inverter (AC output), USB ports, DC outputs, and a solar/AC/DC input charger. Unlike traditional gas generators, they produce no fumes or noise, require no maintenance, and can be recharged from solar panels. Leading brands in 2026 include EcoFlow, Jackery, Bluetti, Anker, and Goal Zero. They range from 256Wh backpack units to 5,000Wh home backup systems.

Can a portable power station run a refrigerator? ▼

Yes. A standard 20 cubic foot refrigerator uses about 150W and 1.5 kWh per day (it cycles on and off). A 2,000 Wh power station can power a standard refrigerator for about 12-16 hours (factoring in inverter efficiency and the compressor start surge). With a 400W solar panel producing 1,700 Wh/day, the station recharges faster than the fridge drains it, making indefinite operation possible on sunny days. For power outage backup, a 2,000-3,000 Wh station is the minimum for keeping a refrigerator cold.

How long does it take to charge a power station with solar? ▼

At 5 peak sun hours and 85% efficiency: a 200W panel produces 200 × 5 × 0.85 = 850 Wh per day. A 1,000 Wh station charges in about 1.2 sunny days. A 2,000 Wh station takes about 2.4 sunny days with a 200W panel. Double the panel to 400W and halve the time. Most power stations accept multiple solar inputs — check your station's maximum solar input spec (e.g., 800W max for EcoFlow Delta Pro) and use the largest array that fits within that limit for fastest charging.

What's the difference between a power station and a traditional battery bank? ▼

A traditional DIY battery bank (like a 12V LiFePO4 battery with a separate inverter and charge controller) is typically cheaper per Wh for larger systems but requires assembly, wiring, and component selection. Portable power stations are all-in-one, safe, and warranty-backed but cost more per Wh. For systems under 2,000 Wh that need portability, power stations are the clear winner. For permanent installations above 3,000 Wh, DIY systems become cost-competitive. For RVs and tiny houses in the 2,000-5,000 Wh range, it's a close call — power stations offer simplicity, DIY offers customization and lower cost.

How many watts of solar panel do I need for a power station? ▼

Rule of thumb: match solar panel wattage to roughly half the power station's Wh capacity. A 1,000 Wh station pairs well with 200W of solar (full recharge in ~1 day of good sun). A 2,000 Wh station pairs with 400W (full recharge in ~1 day). You can add more solar for faster charging or to sustain higher loads — check your station's maximum solar input wattage and don't exceed it. Also check the maximum open-circuit voltage (Voc) — most stations accept 12-150V DC, and some require specific voltage ranges.