What it draws
Laptop
A laptop is unusual in this list because it already contains a battery, which means the question is rarely whether it can run and almost always how many times it can be topped back up. That reframing changes what you need.
Typical draw, and the number that actually applies
Ordinary work sits roughly between 20 and 65 W depending on the machine and what it is doing. Sustained heavy work draws more. The wattage on the supplied power adapter is the ceiling.
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
- 45 W
- Duty share applied
- Continuous
- Average draw for the estimate
- 45 W
Hours from a 1024 Wh battery
Estimated hours from the reference battery at 45 W average draw. An estimate, not a guarantee.
The arithmetic, in full
hours = (rated Wh x 0.85) / average watts
average watts = 45 W running x 1, continuous = 45 W
= (1024 x 0.85) / 45 W = 870 Wh / 45 W
The estimate below assumes a laptop drawing steadily from the battery through a charger. Because the laptop has its own cells, real use looks more like a few charges spread across a day than one continuous draw.
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 over USB-C where the machine supports it and the power station states a USB-C output large enough. Going through the AC inverter to reach a wall brick loses energy at both ends.
- Drop screen brightness and close what is running in the background. Both cut draw more than most people expect.
- Do the work that needs the machine early, while its own battery is still full, and treat the power station as the second charge rather than the first.
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.