Samsung Galaxy S25 Battery Draining Fast? Here’s How to Fix It
The Samsung Galaxy S25 is one of the most capable smartphones available in New Zealand right now. Its Snapdragon 8 Elite processor, stunning AMOLED display, and AI-powered features make it a genuinely impressive device. But there's one thing that frustrates Galaxy S25 owners more than anything else: battery drain.
If your S25 is struggling to last a full day, running hot, or dropping percentage points even when you're not using it — you're not alone. It's one of the most commonly searched issues for this device, and the good news is that there are clear reasons why it happens and clear ways to fix it.
This guide covers everything: the most common causes of Samsung Galaxy S25 battery drain, practical fixes you can try today, the signs that your battery genuinely needs replacing, and how to get it sorted professionally right here in New Zealand.
Why Is My Samsung Galaxy S25 Battery Draining So Fast?
Before jumping to fixes, it's worth understanding what's actually causing the problem. Samsung Galaxy S25 battery drain usually comes down to one of five things.
1. Background Apps running constantly
Apps continue running in the background even when you're not using them — syncing data, refreshing content, and sending notifications. Social media apps, streaming services, navigation apps, and anything with live updates are particularly hungry. If one of these apps has a bug or is stuck in a loop, it can drain your battery surprisingly fast even when your phone is sitting in your pocket.
2. Display settings
The S25's AMOLED screen is beautiful, but it's also one of the biggest battery draws on the device. Running at maximum brightness, keeping the screen on for long periods, and using a high refresh rate all add up quickly. The Always On Display feature is also convenient but costs power continuously.
3. Software bugs after updates
This is a known issue with the Galaxy S25 series. After major One UI updates, the phone often runs background processes for 24 to 72 hours — re-indexing files, rebuilding caches, and relearning usage patterns. Samsung has also released updates that introduced bugs causing unusual battery drain. If your battery life suddenly got worse after an update, software is likely the culprit.
4. Poor network signal
When your phone is in an area with weak 5G or 4G coverage — a basement, a rural area, or parts of a building with poor reception — it works significantly harder to maintain a connection. This dramatically increases power consumption. Many S25 owners in New Zealand have found that switching from 5G to 4G/LTE in low-coverage areas extends their battery life noticeably.
5. Genuine battery degradation
Lithium-ion batteries degrade over time. Every charge cycle reduces their maximum capacity slightly. If your S25 is older or has been through heavy use, the battery may simply no longer hold the charge it once did — and no software fix will solve that. This is when a battery replacement is the right answer.
6 Fixes to Improve Samsung S25 Battery Life
A) Check which Apps are draining your battery
Go to Settings > Battery & Device Care > Battery. You'll see a detailed breakdown of which apps have used the most power over the last 24 hours or 7 days. Look for any app showing an unusually high percentage — especially apps you haven't recently used. If you find one, restrict its background activity or uninstall it and see if things improve.
B) Adjust your Display settings
Go to Settings > Display and make the following changes:-
- Lower screen brightness or enable adaptive brightness
- Set screen timeout to 30 seconds or 1 minute
- Switch on Dark mode (on an OLED screen, black pixels are turned off entirely, saving real power)
- Reduce the refresh rate from 120Hz to 60Hz if you don't need the extra smoothness
- Schedule or limit Always On Display
These adjustments alone can add one to two hours of screen-on time for most users.
C) Update your Software & Apps
Go to Settings > Software update > Download and install to check for the latest One UI version. Then open both the Google Play Store and Galaxy Store and update all apps. Samsung regularly releases patches that address battery drain bugs — keeping everything updated is the simplest and most effective ongoing fix.
D) Limit Background Activity and Location services
Go to Settings > Apps, select any app you don't need running in the background, and restrict its background activity. For location, go to Settings > Location and change any apps set to "Always allow" to "Only while using the app." GPS and location polling in the background are surprisingly heavy on battery.
E) Enable Samsung's Battery Optimization Tools
Go to Settings > Battery and device care and tap Optimise now. This runs a quick scan and closes unnecessary background processes. Also enable Adaptive battery under More battery settings — this uses machine learning to restrict battery access for apps you rarely use. It takes a week or two to fully learn your habits, but it makes a meaningful difference.
F) Switch from 5G to 4G/LTE in low coverage areas
Go to Settings > Connections > Mobile networks > Network mode and switch to 4G/LTE. If you're in a part of New Zealand where 5G coverage is patchy, your phone will spend a lot of energy hunting for a signal. Dropping to 4G gives you a stable connection with much lower power consumption. Switch back to 5G when you're in a well-covered area.
Signs Your Samsung Battery Needs Replacing
If you've worked through all the fixes above and your Samsung Galaxy S25 is still struggling, the problem is likely the battery itself rather than software or settings. Here are the signs that point clearly to a genuine battery replacement:
1) Your phone shuts down unexpectedly
If your S25 switches off at 15–30% battery, the battery can no longer accurately hold or report its charge. This is a classic sign of a degraded cell.
2) The battery drains from 100% to low within a few hours of light use
A healthy S25 battery should comfortably last a full day of normal use. If you're seeing significant drain by mid-morning without heavy use, the battery's capacity has likely dropped well below its original specification.
3) The phone runs warm even during basic tasks
A degraded battery works harder to deliver power, generating more heat in the process. If your S25 feels warm when you're just browsing or reading, that heat is often coming from a stressed battery.
4) The back of the phone appears to be bulging
This is a serious warning sign. A swollen battery is a safety issue and should be addressed immediately — do not charge the phone further and get it looked at right away.
Samsung Galaxy S25 Battery Replacement in New Zealand
A battery replacement is the most cost-effective way to restore your Galaxy S25 to full performance. Compared to buying a new device — which can cost $1,500 or more for a current Samsung flagship — a professional battery replacement is a fraction of the price and gives you a phone that performs like new again.
At Phone Parts NZ, we are New Zealand's largest locally owned and operated phone parts and repair specialists. Our technicians carry out Samsung battery replacements using quality replacement parts, and we serve customers across New Zealand with fast turnaround times.
There are three easy ways to get started:
View our repair services → Browse the full range of Samsung repair services we offer, including battery replacement, screen repair, charging port repair, and more.
Request a quote → Not sure what your repair will cost? Submit a quick quote request and our team will come back to you with pricing and a clear assessment — no obligation, no surprise fees.
Book a repair → Ready to get it sorted? Book your Samsung Galaxy S25 battery replacement directly online and lock in a time that suits you.
Don't Put Up With a Battery That Lets You Down
A Samsung Galaxy S25 that won't hold charge is frustrating — but it's a solvable problem. Most battery drain issues are fixed with a few software adjustments. And when the battery itself is the issue, a professional replacement at Phone Parts NZ gets you back to a full day's charge without the cost of a new device.
Whether you need a quote, want to book a repair, or just want to talk through your options, our team is here to help.
Explore our repair services at Phone Parts NZ →
