I recently bought an Anker Zolo 10,000mAh power bank rated for 22.5W and want to use it with my Samsung Galaxy S25 Ultra. I've seen claims that I need a 45W power bank, matching the phone's wall charger, or the battery could become weaker over time. A 45W model is outside my budget, so I'd like to know whether the 22.5W power bank is safe and what difference the lower wattage actually makes. I'm also wondering whether using a wall charger rated below 45W is safe for the same phone.
4 Answers
That power bank is perfectly suitable. The phone only draws the power it can safely use, and a 22.5W bank will simply charge it more slowly than a 45W charger. Using a lower wattage does not weaken the battery. In fact, slower charging often produces less heat, which can be easier on battery longevity.
Heat matters more than simply choosing the highest wattage. Fast charging can make the phone noticeably warmer, while a slower charger may keep temperatures lower. Avoiding excessive heat is generally helpful for battery health, but you do not need to avoid fast charging completely when you need it.
If you plan to take the power bank on a flight, check the airline’s current rules first. Airlines usually limit power banks based on their watt-hour capacity and may require them to be carried in hand luggage rather than checked baggage.
Anker is generally a reputable brand, so the power bank should be fine for normal use. A 45W charger is mainly useful when you need the fastest possible recharge, such as during a short stop while traveling. A lower-rated wall charger is also safe; it will just take longer to charge the phone, provided the charger and cable are from a reliable manufacturer.
So using a wall charger below 45W is safe too, as long as it is a decent-quality charger?
Thanks, that clears up the battery concern.