Watt-hours: how long it lasts
Watt-hours (Wh) 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 (like a CPAP machine or router) lasts roughly 8-10 hours accounting for conversion losses. Small stations (150-300Wh) suit phones, laptops, and camping lights for a day or two; mid-size stations (500-1,000Wh) handle a mini-fridge or CPAP overnight; large stations (1,500-3,000+Wh) can run power tools, larger appliances, or several devices through a multi-day outage.
Output watts: what you can actually plug in
Continuous output wattage (often 300W-3,000W+ depending on model) caps what you can run simultaneously, and surge wattage matters for motor-driven devices the same 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, before buying.
Recharge methods and speed
Most power stations recharge from a wall outlet (fastest, often 1-2 hours for mid-size units with fast-charge circuitry), a car's 12V outlet (slower, useful while driving), or solar panels (variable, dependent on sun and panel wattage). If you're planning off-grid or extended outage use, prioritize a model with a high maximum solar input wattage so panels can refill it in a reasonable window rather than trickle-charging over days.
Sizing solar panels to match the station
As a rough rule, a solar array's rated wattage should be roughly 1-1.5x the power station's maximum solar input to reach full charging speed on a clear day, and realistic daily solar harvest is often only 20-30% of a panel's rated wattage once you average in weather, angle, and season. 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 faster refill.
Choosing battery chemistry: LiFePO4 vs standard lithium-ion
LiFePO4 (lithium iron phosphate) batteries cost somewhat more upfront but rate for roughly 2,000-3,500+ charge cycles versus 500-1,000 for standard lithium-ion, translating to many more years of service, plus better thermal stability. For daily or frequent-use scenarios (regular camping, daily solar cycling, or as a home backup you test often), LiFePO4's longevity generally pays for itself; for rare emergency-only use, standard lithium-ion can be a reasonable lower-cost option.
Frequently asked questions
What size power station do I need to run 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 some margin.
Can a power station run a full-size refrigerator?
Only larger units with 2,000W+ continuous output and 2,000Wh+ capacity can reliably run a full-size refrigerator's starting surge and sustain it for more than a few hours; check the fridge's compressor starting watts specifically before assuming any station will work.
How many solar panels do I need to fully recharge a power station in a day?
As a starting estimate, pair a solar array rated at roughly 1-1.5x the station's max solar input wattage, 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 over standard lithium-ion?
For frequent or daily use, yes, since LiFePO4 batteries last roughly 3-5x more charge cycles; for occasional emergency backup use, a standard lithium-ion station can be a reasonable budget option.