Conaway provided a basic formula to determine how long a portable power station will power your devices while camping.
Device A. Wattage x number of hours = Power A
Device B. Wattage x number of hours = Power B
Device C. Wattage x number of hours = Power C
PowerA + PowerB + PowerC = Total daily power or (TDP)
“My general recommendation is to match solar panels (if you plan to recharge by solar) roughly equivalent to your daily power consumption, then choose a power station with a capacity of at least 2x the capacity you need for 24 hours,” Conaway said. “If you’re only planning two-to-three-day trips, you can cut down on either total capacity or solar recharge.”
He said that once you calculate your TDP, divide that into your total capacity to determine how long you’ll have power.
“It is rarely a straightforward answer since devices are likely to be charged at different times/intervals anyway,” Conaway added. “You’re usually going to see somewhere around 85-90% usable capacity of whatever the power station’s stated capacity is.”