Solar generators: how many panel watts do you actually need?
A "solar generator" is a portable power station plus solar panels. The panels decide how fast you refill; the battery decides how long you last overnight. Here's how to size both, with honest real-world numbers.
What a solar generator is (and isn't)
It's a battery, an inverter and a solar charge controller in one box. You plug panels into the solar input, and the box charges itself while running your devices. There's no engine, fuel or exhaust, so it's quiet and safe indoors, but it only produces as much energy as the sun puts back in.
It isn't a whole-home solar system. Rooftop solar with a home battery is wired into your electrical panel and sized in tens of kilowatt-hours. A portable solar generator is for essentials, camping and RVs, or as a plug-in backup.
How many solar panel watts do you need?
To replace what you use each day:
The 0.75 factor reflects real conditions: panel angle, heat, dust, wiring and charge-controller losses. Example: you use 1,200 Wh a day and get 4.5 peak sun hours. 1,200 ÷ (4.5 × 0.75) ≈ 360 W of panels, so two 200 W panels.
Peak sun hours across the U.S.
"Peak sun hours" means the number of hours of full-strength (1,000 W/m²) sunlight a day delivers. These are rough year-round averages for a well-angled panel. Winter can be 30–50% lower in northern states. For your exact ZIP code, check NREL's free PVWatts tool.
| Region | Typical peak sun hours | Winter (approx.) |
|---|---|---|
| Southwest (AZ, NM, NV, inland CA) | 5.5–6.5 | 4–5 |
| Texas, Southeast, Florida | 4.5–5.5 | 3.5–4.5 |
| Mountain West, Great Plains | 4.5–5.5 | 3–4 |
| Midwest, Mid-Atlantic | 4–4.5 | 2–3 |
| Northeast, Great Lakes | 3.5–4.5 | 1.5–2.5 |
| Pacific Northwest | 3–4 | 1–2 |
How long will solar take to charge my station?
| Battery | 200 W of panels | 400 W | 800 W |
|---|---|---|---|
| 300 Wh | ≈2 sun hours | ≈1 (if input allows) | n/a |
| 1,000 Wh | ≈6.7 (about 1.5 days) | ≈3.3 | ≈1.7 |
| 2,000 Wh | ≈13 (about 3 days) | ≈6.7 | ≈3.3 |
| 3,800 Wh | ≈25 | ≈12.7 | ≈6.3 |
That's why a 2 kWh station with a single 200 W panel is a slow combination. Match panel watts to the station's maximum solar input if you want same-day recharges.
Input limits that trip people up
- Maximum solar input (W). Extra panels beyond the limit don't charge faster. Many 1 kWh units cap at 200–500 W; larger units allow 1,000 W or more.
- Voltage window (V). Panels wired in series add voltage. Exceeding the station's maximum input voltage can damage it, so check the "PV input" range (for example 12–60 V) before wiring panels in series.
- Connector type. Most stations use XT60 or Anderson inputs. Panels usually ship with MC4 connectors, so you may need an adapter cable.
- Shading. Partial shade on one cell can cut a panel's output dramatically. Foldable panels should face the sun and be re-angled a few times a day.
Panel sizes for the models we compare
| Station | Capacity | Max solar input | Sensible panel set |
|---|---|---|---|
| Elite 30 V2 | 288 Wh | 200 W | 100–200 W foldable |
| AC180 | 1,152 Wh | 500 W | 2 × 200 W (400 W) |
| Elite 200 V2 | 2,074 Wh | 1,000 W | 3–4 × 200–250 W, checking the voltage window |
| Elite 400 | 3,840 Wh | 1,000 W | 1,000 W total, checking the voltage window |
| Apex 300 | 2,765 Wh base | Up to 4,000 W (with add-on controller) | Rigid rooftop or ground array; installer recommended |
Solar input figures are from manufacturer pages (checked Nov 15, 2026). Some units require an accessory to reach their maximum. Confirm on the listing.
Solar generator calculator
Enter your solar panel watts and local sun hours in step 3. The capacity result accounts for daily solar recharge.