“How many panels?” is really the wrong question. What you want to know is how many watts of solar it takes to replace what you use each day. Once you have that, it doesn’t matter much whether you buy it as one 400 W panel or four 100 W ones.
Step 1: Know your daily use
Add up your essential appliances in watt-hours per day; the power station size calculator does this for you. Some typical totals:
- Phones, router and lights: about 700 Wh a day
- Add a refrigerator: about 2,100 Wh a day
- Add a chest freezer: about 2,900 Wh a day
Step 2: Find your peak sun hours
| Region | Avg. peak sun hours | Winter |
|---|---|---|
| Desert Southwest | 6–7 | 4.5–5.5 |
| CA, TX, FL, CO | 5–5.5 | 3.5–4.5 |
| Southeast & Midwest | 4–4.5 | 2.5–3.5 |
| Northeast & Great Lakes | 3.5–4 | 2–2.5 |
| Pacific Northwest | 3–3.5 | 1–2 |
If winter storms are what worry you, plan around the winter number. If it’s hurricane season or summer heat, plan around summer.
Step 3: Do the math
Panel watts needed = daily Wh ÷ (peak sun hours × 0.75)
The 0.75 accounts for real-world losses from heat, angle, dust, cables and the charge controller.
For example, 2,100 Wh a day in the Midwest (4.5 sun hours):
2,100 ÷ (4.5 × 0.75) ≈ 620 W of panels
| Daily use | 3.5 sun hours | 4.5 sun hours | 5.5 sun hours |
|---|---|---|---|
| 700 Wh | 270 W | 210 W | 170 W |
| 1,500 Wh | 570 W | 440 W | 360 W |
| 2,100 Wh | 800 W | 620 W | 510 W |
| 3,000 Wh | 1,140 W | 890 W | 730 W |
The solar panel calculator does this for your location.
Step 4: Check what your power station can take
There’s a limit to how much solar a power station accepts. Many 1 kWh units take 200–600 W, and bigger systems 1,600–2,400 W. There’s also a voltage window, something like 11–60 V per input, so remember that series wiring adds up voltages and parallel wiring adds up current. Some units have two solar inputs you can use at once.
If what you need each day is more than the input can take, you’ll need a bigger station or fewer loads.
Typical setups
| Goal | Typical panel kit |
|---|---|
| Phones, router, lights indefinitely | 200 W |
| Fridge + essentials (summer) | 400–600 W |
| Fridge + essentials (winter) | 800 W+ |
| Fridge, freezer, sump, fans | 1,000–1,600 W with a 3.6 kWh+ station |
Getting more from each panel
- Tilt them toward the sun and re-aim them a few times a day. That’s worth up to 30% more energy than leaving them flat.
- Keep them out of all shade, even from a chimney or a branch.
- Keep them clean.
- Use short, thick cables between the panels and the station.
A simple rule of thumb
In most of the U.S., plan on about 300 W of solar for every 1 kWh you use a day, and more in winter or in cloudy regions. Start with whatever your budget and your power station’s input allow. Even a partial solar setup makes a big difference to how long you can ride out an outage.