Estimate daily amp-hours into the battery from panel watts, peak sun hours, system efficiency, and battery volts. You enter sun hours and efficiency — we do not invent location insolation maps. Harvest-only math, not a full array-design tool.
Enter panel array watts, peak sun hours / day, system efficiency (0–1), and battery bank volts.
Estimate daily amp-hours into the battery from panel watts, peak sun hours, system efficiency, and battery volts.
Daily amp-hours ≈ panel watts times peak sun hours times system efficiency, divided by battery volts.
daily_Ah ≈ (panel_watts × peak_sun_hours × system_eff) / battery_volts
Harvest-only. No location insolation maps or vendor array sizing.
Start with the calculator’s default entries: Panel array watts = 200; Peak sun hours / day = 4.5; System efficiency (0–1) = 0.75; Battery bank volts = 12.
With those entries the calculator returns:
56.3 Ah / day
675 Wh harvest · eff 0.75
Wh ≈ 200 × 4.5 × 0.75 = 675.0 Wh
daily_Ah ≈ 675.0 ÷ 12 = 56.25 Ah
Formula used: daily_Ah ≈ (panel_watts × peak_sun_hours × system_eff) / battery_volts
One input at a time. Raise Panel array watts from 200 to 300 and leave everything else alone. The result becomes:
84.4 Ah / day
1013 Wh harvest · eff 0.75
Wh ≈ 300 × 4.5 × 0.75 = 1012.5 Wh
daily_Ah ≈ 1012.5 ÷ 12 = 84.38 Ah
Assumptions: inputs for this solar harvest ah estimate match the hints (soundings, nameplate Ah, marked tank capacity, and so on).
Equivalent full-sun hours for your site and season. Enter a value from a reliable source for your location — we do not invent maps.
Controller, wiring, heat, and angle losses. Many planners start near 0.70–0.75 unless you measure better.
Reflected in the efficiency you enter, not as a separate OEM table on this page.