Power Banks & Power Stations
Capacity tells you what a battery holds. The input tells you how long it takes to come back.
This guide covers everything that stores charge rather than converting it: how to size a power bank for a multi-day outage, how power stations are recharged, and the battery-health and safety rules that decide whether either lasts.
- Three routes below cover the sizing, the inputs and the battery
- 18 guides organised by the question they answer
- Every route ends at a capacity, an input profile and a safety rule
Three routes, and you only need one of them
Sizing the battery, charging it and keeping it healthy are three different questions. Start with the one you are asking.
Size the battery
Rated capacity is not usable capacity, and the difference is what separates a power bank that covers an outage from one that does not.
Charge the battery, not just use it
A power station is only as useful as its input. How you refill it decides whether it is ready when the next outage arrives.
Keep it healthy and compliant
Batteries age, swell and fall under regulation. Those three facts decide the product range as much as the capacity does.
Lamps, lights and the desk
Two adjacent uses sit either side of this cluster: products that combine a battery with a light, and the decision between a charger and a battery on a desk.
Dual-use emergency products
A lamp with a USB output sells on the same outage demand as a power bank, and it competes for the same shelf. The distinction that matters is whether the battery is sized for lighting or for charging a phone — products that attempt both usually disappoint at one.
Charger or power bank on the desk
At a desk with a socket, a charger wins on almost every measure. The power bank earns its place when the device moves, which turns the decision into a question about elapsed time rather than capacity.
What actually decides whether a power bank works when it matters
Four things, in this order. The capacity printed on the case is the least useful of them.
Usable capacity after conversion
A cell rated at 20,000mAh delivers considerably less at the port once conversion losses are counted. The number that matters is the rated output watt-hours, not the cell capacity on the label.
The input profile
A large power station recharged at 45W takes most of a day; the same unit on a 140W PD input takes a couple of hours. Input capability, not output, decides whether a battery is ready for the next event.
Temperature in service
Both charging and discharging generate heat, and lithium cells age faster at the extremes. A battery stored in a hot car loses capacity permanently, regardless of its cycle count.
Regulation and transport rules
Battery products carry design duties in the EU and transport restrictions everywhere. Those constraints shape the cell choice and the packaging long before the capacity is finalised.
Where to go from here
The battery cluster connects to four neighbours. Pick the one that matches your next question.
Power bank questions
The short answers. Each one links into the guide that covers it properly.
What capacity power bank do I need for an outage?
Work from the devices rather than the days. A phone holds roughly 15Wh, so a 100Wh bank covers several phone charges; a laptop is 50 to 100Wh, which changes the arithmetic entirely. Size for the device list, not for the marketing number.
Why is my power bank capacity lower than advertised?
Because the cell rating is measured at cell voltage and the port delivers at a different one, so conversion losses take a share. A bank advertising 20,000mAh typically delivers around 12,000 to 14,000mAh at the port.
How do I charge a portable power station faster?
Use its highest-rated input. Many stations accept USB-C PD alongside a mains input, and the PD path often matters more when the mains is unavailable. Check the input profile of the specific model rather than assuming PD will be accepted.
Should I worry about a swollen power bank?
Yes, and the response is specific: stop using it, do not charge it, do not puncture it, and dispose of it through a battery collection point rather than household waste. Swelling is a cell failure, not a worn battery.
Does fast charging shorten a battery life?
It raises the temperature, and sustained heat is what ages a cell. On a well-designed device the charge management limits the damage, so the practical advice is to avoid charging in hot places rather than to avoid fast charging altogether.
Request a battery review
Send us the device list and the use case — commute, travel or multi-day outage. We will come back with the usable capacity that covers it, the input profile that refills in time, and the battery regulation the target markets require.