Samsung Galaxy
Samsung's most reliable check works on almost every Galaxy phone:
- Open the Samsung Members app (it comes installed; get it from the Galaxy Store if not).
- Tap Support, then Phone diagnostics.
- Tap Battery status.
You'll see a verdict such as Normal, Weak or Bad. "Weak" or "Bad" means it's time for a new battery.
On newer Galaxy phones and software, Settings → Battery → Battery information can also show the battery's health and cycle count. Whether it appears depends on the model, the region and the software version, so if you don't see it, use Samsung Members.
Battery protection. In Settings → Battery, Galaxy phones offer a protection setting that can stop charging at 80% or 85%. If your phone never charges past that, this is why, and it's doing your battery a favour.
Oppo
Many recent Oppo phones show battery health under Settings → Battery (look for Battery health or similar wording; it varies with the model and ColorOS version). A maximum capacity under about 80% means the battery has noticeably worn.
What the numbers mean
A lithium-ion battery slowly loses capacity with every charge cycle (using 100% of its capacity in total, not one charge). About 80% is where most makers draw the line: the phone still works, but it runs out noticeably sooner, and it may struggle with bursts of power when the charge is low or it's cold.
Third-party battery apps can give a rough idea, but they estimate from how the phone charges. Trust the phone's own reading, or the signs below.
Signs your phone needs a new battery
- It drops quickly once it's under 30%, or switches off with charge left.
- It can't get through a day it used to manage easily.
- It gets warm while charging or doing simple things.
- It charges much more slowly than before, or stops charging partway (also check the charging port).
- The back or the screen is bulging, or there's a gap at the edge. That's a swollen battery: stop using and charging it, and read what to do about a swollen battery.
Making your battery last longer
- Keep it cool. Heat wears batteries fastest. Don't leave the phone in a parked car or on a sunny dashboard, and take a thick case off if it heats up while charging.
- Use the 80% or 85% charge limit if you usually have a charger nearby.
- Use a good charger. The phone's own, or a reputable brand with the right standard (USB-C Power Delivery, or Samsung's "Super Fast Charging" for Galaxy phones).
- Top up whenever suits you. Small charges through the day don't harm a modern battery.
Sources
- Samsung Australia: Samsung Members app
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