Solar panel pairing calculator
How long to refill your power station with a portable solar panel? How many days can you stay off-grid? Realistic numbers — accounting for ~78% nameplate-to-real production ratio and ~92% charge controller efficiency.
Approximate peak sun hours: Southwest US 6.0 · Texas 5.5 · Midwest 4.5 · Pacific NW 3.5 · Northeast winter 3.0
Off-grid days assumes you're using up the full capacity daily. Cut that in half if you also want to keep a reserve.
Why the 78% factor?
A "200 W" panel rarely delivers 200 W in the field. Real factors: panel angle vs. sun, partial cloud, dust, temperature derating, and minor MPPT mismatch with the power station. Independent tests on portable folding panels consistently show 75–85% of nameplate. We use 78% as a conservative middle ground.
For fixed roof-mounted residential panels, the ratio is higher (~85–90%) but those aren't typical for portable power stations.
Frequently asked questions
Why the 78% derating from nameplate panel rating?
Real-world tests across BougeRV, Renogy, EcoFlow, Jackery, and Goal Zero panels consistently show 75–85% of nameplate output under typical conditions. Causes: panel angle versus sun (you're rarely perpendicular with portable panels), partial cloud, dust film, temperature derating (cells lose efficiency when hot), and minor MPPT mismatch with the power station. 78% is a conservative middle estimate.
Where do I find peak sun hours for my location?
NREL's PVWatts tool gives precise per-ZIP-code values. Quick estimates: Southwest US 5.5–6.5 hours, Texas/Florida 5.0–5.5, Midwest 4.0–4.5, Northeast 3.5–4.0, Pacific Northwest 3.0–3.5. Subtract 20–30% for winter, add 15–20% for summer.
Will my power station accept any solar panel?
No. Check three things: connector (XT60, MC4, 8mm — most include adapters), open-circuit voltage (must be inside the input range listed on your power station's spec sheet — exceeding it can damage the charge controller), and short-circuit current (must be inside the input amp rating). Brand panels paired with same-brand power stations always work; mixing brands needs the spec check.
Is one big panel better than two smaller ones?
Usually yes — fewer cables, less voltage drop, more reliable MPPT tracking. But two smaller panels give you flexibility (split across hood + roof, point each at different angles, use one when the other is shaded). For RV/van life, parallel two 100 W panels often beats a single 200 W panel because of partial shading from trees.