What it draws
Phone Charging
Phones are the load everyone worries about and the one that costs the least. A full charge is a small fraction of even a modest power station, which means the real question is not capacity but whether anything is charged when the outage starts.
Typical draw, and the number that actually applies
A phone charging over USB typically pulls in the range of 5 to 25 W depending on the charger and the state of the battery, and drops toward nothing once full. The wattage printed on the charging brick is a ceiling, not a reading.
Read the nameplate. It is usually a sticker on the back, inside a door, or on the power adapter, and the figure printed there is a maximum for that specific unit rather than a typical reading. Any range on this page is a starting point for arithmetic, not a substitute for that label.
- Running watts used here
- 12 W
- Duty share applied
- Continuous
- Average draw for the estimate
- 12 W
Hours from a 1024 Wh battery
The row stops at 24 blocks; the estimate runs past it. Estimated hours from the reference battery at 12 W average draw. An estimate, not a guarantee.
The arithmetic, in full
hours = (rated Wh x 0.85) / average watts
average watts = 12 W running x 1, continuous = 12 W
= (1024 x 0.85) / 12 W = 870 Wh / 12 W
The estimate below treats one phone charging steadily. In practice a phone stops drawing once it is full, so a household of four phones costs a power station far less over a day than continuous charging suggests.
The derate of 0.85 covers inverter conversion loss and the share of rated capacity a pack will not hand back. It is one planning figure applied to every unit on this site, not a measurement of any particular model.
Starting surge
This load has no meaningful starting surge. It draws essentially the same at switch-on as it does a minute later, which makes it one of the easy ones: if the continuous output is large enough, the load will run.
Duty cycle
This load draws continuously while it is switched on, so no duty share is applied and the average draw is the running draw. Switching it off is the only thing that reduces it.
How to get by without powering it
Every watt-hour you do not spend is one you still have. These are the moves that cost nothing.
- Charge everything as soon as an outage looks likely. A charged phone before the power goes out is worth more than any battery bought after.
- Charge over USB directly from the power station rather than through a wall brick plugged into the AC outlet. Going through the inverter to reach a charger wastes energy for no reason.
- Turn on the phone's low power mode and drop the screen brightness. Both extend the phone far more than a larger battery would.
Where this sits in the sequence
This load becomes realistic at stage 2, and not before. Read that stage including the part about what it does not cover, because the limits are the useful half.
Related gear
Products live on the gear pages rather than here, because the decision on this page is about arithmetic and the decision there is about hardware.