Solar Charge-Time Math: 200 W vs 400 W Input Charts
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This page is arithmetic + manufacturer max-input limits, not outdoor irradiance testing by Watt Weekender. Real charge times depend on sun angle, temperature, panel orientation, cable loss, and the station’s MPPT window.
Related: camping solar needs · home backup EcoFlow vs Anker · fridge loads while recharging
Core formula
Hours (ideal) ≈ (Battery Wh × derate) / (Effective solar watts into battery)
Where derate accounts for charging inefficiency. A common planning derate is 1.15–1.4×. Manufacturers sometimes publish “full charge in X hours” under lab conditions — treat as best-case.
Effective solar watts ≤ min(real panel output, station max solar/DC input).
Input caps (official)
| Station | Max solar / DC input (mfr) | Source |
|---|---|---|
| EcoFlow DELTA 3 | 500 W (11–60 V) | EcoFlow US |
| EcoFlow RIVER 2 Max | 220 W (11–50 V, 13 A) | RIVER 2 Max |
| Anker SOLIX C1000 | 600 W (11–60 V) | C1000 |
| Anker SOLIX C300 | 100 W (11–28 V XT60; panel constraints) | C300 |
| BLUETTI Elite 100 V2 | 1,000 W (12–60 V, 20 A) | BLUETTI |
| Jackery Explorer 1000 v2 | 400 W total dual DC8020 (200 W/port class) | Jackery FAQ |
A 400 W array cannot push 400 W into a 100 W-capped station.
Idealized charts
~288 Wh pack (derate 1.25 → need ≈360 Wh)
| Effective input | Ideal hours |
|---|---|
| 100 W | ≈3.6 h |
| 200 W | ≈1.8 h |
~512 Wh pack (derate 1.25 → need ≈640 Wh)
| Effective input | Ideal hours | Note |
|---|---|---|
| 110 W | ≈5.8 h | Near RIVER 2 solar class |
| 200 W | ≈3.2 h | Only if station accepts ≥200 W |
| 220 W | ≈2.9 h | RIVER 2 Max max |
~1,024–1,070 Wh pack (derate 1.25 → need ≈1,280–1,340 Wh)
| Effective input | Ideal hours | Who can take it |
|---|---|---|
| 100 W | ≈12.8–13.4 h | Small inputs / poor sun |
| 200 W | ≈6.4–6.7 h | Common portable dual 100 W |
| 400 W | ≈3.2–3.4 h | Jackery 1000 v2 max band |
| 500 W | ≈2.6 h | DELTA 3 max |
| 600 W | ≈2.1–2.2 h | C1000 max |
| 1,000 W | ≈1.3 h | Elite 100 V2 max |
EcoFlow markets DELTA 3 ≈2 hours at 500 W MPPT under their tests; Anker cites C1000 ≈1.8 hours full solar under theirs — order-of-magnitude aligned, weather not included.
200 W vs 400 W (same station)
If the station accepts both, doubling effective input halves ideal time. Field average often 50–80% of STC panel rating, so “400 W of panels” may behave like 200–320 W for hours — still usually faster than one 200 W panel, not always a clean 2×.
Worked weekend scenario
Camp fridge budget ~1,200 Wh/day (camping article example). You run a cooler from a 1,070 Wh Jackery and want to replace 800 Wh by sunset.
- Need ~800 × 1.25 = 1,000 Wh into battery
- At 200 W effective: 5 h sun
- At 400 W effective: 2.5 h sun
If clouds cut you to 150 W average, you need ~6.7 h — plan loads accordingly.
Planning checklist
- Voltage + connector compatibility.
- Max input watts.
- Size panels ≤ cap (or accept clipping).
- Apply derate; don’t bet critical loads on brochure times.
- Pair with load-side calculator.
Last reviewed: 2026-09-24 (MDT).