Watt-hours: how long the charge lasts
Watt-hours measure total stored energy. To estimate runtime, divide the station's Wh rating by the device's running watts — a 500Wh station running a 50W device (a CPAP machine or router, say) lasts roughly 8-10 hours after accounting for conversion losses. Small stations (150-300Wh) cover phones, laptops, and camping lights for a day or two. Mid-size stations (500-1,000Wh) run a mini-fridge or CPAP overnight. Large stations (1,500-3,000+Wh) run power tools, larger appliances, or several devices through a multi-day outage.
Output watts: what you can actually plug in
Continuous output (often 300W-3,000W+ depending on model) caps what you can run simultaneously, and surge wattage matters for motor-driven devices exactly the way it does for generators. A high-Wh station with low output watts can still fail to start a compressor fridge or power tool — check both numbers against your actual devices, not just total capacity.
Recharge methods and speed
Most stations recharge from a wall outlet (fastest, often 1-2 hours on mid-size units with fast-charge circuitry), a car's 12V outlet (slower, useful on the road), or solar panels (variable, dependent on sun and panel wattage). Planning off-grid or extended-outage use means prioritizing a model with high maximum solar input wattage, so panels refill it in a reasonable window instead of trickle-charging for days.
Sizing solar panels to the station
As a rough rule, a solar array's rated wattage should run roughly 1-1.5x the station's maximum solar input to reach full charging speed on a clear day, and realistic daily harvest often lands at only 20-30% of a panel's rated wattage once weather, angle, and season factor in. For a 1,000Wh station used daily off-grid, a 200-300W panel array is a reasonable starting point, more if you're in a cloudy climate or need a faster refill.
LiFePO4 vs standard lithium-ion
LiFePO4 (lithium iron phosphate) batteries cost somewhat more upfront but rate for roughly 2,000-3,500+ charge cycles against 500-1,000 for standard lithium-ion — many more years of service, plus better thermal stability. Daily or frequent-use scenarios (regular camping, daily solar cycling, a home backup you test often) make LiFePO4's longevity pay for itself. For rare emergency-only use, standard lithium-ion is a reasonable lower-cost option.
Frequently asked questions
What size station runs a mini-fridge overnight?
A mini-fridge draws roughly 60-100 running watts with brief startup surges, so a 500-800Wh station typically covers 8-12 hours of overnight operation with margin to spare.
Can a power station run a full-size refrigerator?
Only larger units with 2,000W+ continuous output and 2,000Wh+ capacity reliably handle a full-size refrigerator's starting surge and sustain it beyond a few hours. Check the fridge's compressor starting watts before assuming any station will work.
How many solar panels fully recharge a station in a day?
Pair a solar array rated at roughly 1-1.5x the station's max solar input wattage as a starting estimate, then expect real-world daily harvest of only 20-30% of that rated wattage due to weather and sun angle.
Is LiFePO4 worth the extra cost?
For frequent or daily use, yes — LiFePO4 batteries last roughly 3-5x more charge cycles. For occasional emergency backup, a standard lithium-ion station is a reasonable budget option.