What are realistic expectations for portable panel charging times?

Estimating charging times with portable solar panels

Charging times depend on panel wattage, battery capacity, sun conditions, and charge controller efficiency. A rough estimate helps plan usage.

How to estimate:

• Divide battery capacity (Wh) by panel wattage under ideal sun to get hours (e.g., 500 Wh / 100 W = 5 hours)
• Factor in real-world conditions: typical 60–80% of nameplate output due to angle, heat, and clouds
• Include charge controller losses (around 5–10%)

Example: a 100 W panel might realistically deliver 60–80 W average under good sun, so charging a 500 Wh battery could take 6–8 hours. Use larger panels or multiple panels in parallel to reduce charging time if needed.