Solar generator recharge time calculator

Select your US state, month, solar panel wattage, and power station capacity to see recharge days and peak-equivalent sun hours from NREL PVWatts V8 reference data.

Recharging 819 Wh in Ohio during July takes about 0.5 sunny-average days (2.3 hours of peak-equivalent sun).

NREL PVWatts V8 reference for Columbus, OH: 141.66 kWh/month per 1 kW DC (4.57 kWh/kW/day), yielding 1,645 Wh/day from 400 W of panels at 90% MPPT charge efficiency.

Panels laid flat on the ground, partial shade, and cloud cover lower daily output; NREL PVWatts uses typical-year weather for a fixed array tilted at latitude.

1. Location and month
2. Solar panels and power station

Share of DC panel output stored in the battery after MPPT controller and cell charging losses (assumption: 0.90 default).

Lowest $/Wh stations accepting at least 400 W of solar input

Power stations with solar input at or above 400 W sorted by cost per watt-hour
$/WhPriceCapacitySolar maxChemistryProduct
$0.17$1,029
at EcoFlow Store, as of 2026-11-06
6,144 Wh1,000 WLiFePO4EcoFlow DELTA 2 Max Portable Power Station
$0.26$1,579
at EcoFlow Store, as of 2026-11-06
6,144 Wh1,000 WLiFePO4EcoFlow DELTA 2 Max Solar Generator
$0.29$899
at Pecron Store, as of 2026-11-06
3,072 Wh1,600 WLiFePO4Pecron F3000LFP Portable Power Station 3600W 3072Wh

How NREL PVWatts V8 estimates daily solar yield by state and month

Our database stores NREL PVWatts V8 monthly direct-current (DC) kilowatt-hour production for a 1 kW fixed array tilted at latitude in each state's most populous city. Dividing monthly production by the number of days in that month gives daily yield per kilowatt of panels.

Portable folding panels placed flat on the ground, aimed away from true south, or shaded by trees produce less energy than a fixed array. Size your battery first on our portable power station runtime calculator or compare recharging costs on our generator vs power station cost per kWh calculator.