If a Galaxy A55's battery started draining twice as fast, look at the One UI 7 update. Many owners in Samsung's forums reported the A55 losing battery about twice as quickly and heating abruptly after One UI 7, with slower charging too, while others said their battery life improved from two days to three. Samsung's own explanation for post-update drain is the phone re-optimizing apps for a few days, so wait three days before you change settings, then look at the top of Settings, Battery.
Differential
Likely causes of “Samsung Galaxy A-series family battery drains too quickly”, and how to tell them apart
- 1
The phone re-optimizing after One UI 7
What separates it Heat and drain for the first days after the update
How to confirm Wait three days on Wi-Fi and the charger, then recheck
- 2
An app not yet updated for One UI 7
What separates it One app leads Settings, Battery
How to confirm Update it in the Play Store or Galaxy Store
- 3
Screen and 5G use
What separates it Screen-on time is long
How to confirm Lower brightness and compare a day on Wi-Fi
- 4
A worn battery
What separates it Drain continued after the settle period
How to confirm Samsung Members' battery test reports the cell
Before you touch a setting
Record this first — changing settings destroys the evidence
- Whether the drain began at One UI 7
- The top three apps in Settings, Battery
- Hours of screen-on time
- Whether charging is slower too
Try in this order
0 of 4 completedWait three days
ReversibleLeave the phone on Wi-Fi and the charger overnight after the update.
Read the battery list
ReversibleOpen Settings, Battery and update the leading app.
Restart
ReversibleHold Power and Volume down for about 10 seconds.
Run the battery test
ReversibleOpen Samsung Members, Support, Phone diagnostics, Battery.
Model-specific
What is true of this model and not of its siblings
- Battery
- Wikipedia lists a 5,000 mAh battery with 25W wired charging for the A55.
- The A55 in brief
- A 6.6-inch AMOLED screen at up to 120 Hz, a 5,000 mAh battery, 25 W wired charging, no wireless charging, IP67 water resistance and Samsung's promise of several years of updates, so a battery fault is worth fixing rather than ignoring.
- A habit that helps on a mid-range A phone
- Leaving 5G on in a weak-signal area is the most common hidden drain; Settings, Connections, Mobile networks lets you drop to LTE where signal is poor.
- Other models this page answers
- These steps also fit the Galaxy A54 5G.
Stop boundary
When this stops being a self-service repair
- !If drain continues after a week and an app update, run Samsung Members diagnostics and contact Samsung support
- !If the back bulges, stop charging and go the same day
Evidence ledger
Sources behind this answer
A solved thread from A55 owners.
Owners describing drain after One UI 7.
Heating and drain reports.
A55 battery, charging, chip, storage, Wi-Fi, display, glass and SIM tray.
Exact questions
Common questions
Did One UI 7 drain the A55 battery?+
Many owners in Samsung's forums said it drained twice as fast after One UI 7 and heated, while others reported longer battery life.
Will the drain stop?+
Samsung's explanation is the phone re-optimizing apps after an update; if it continues after a few days, the battery test is the next step.
How big is the A55 battery?+
Wikipedia lists a 5,000 mAh battery with 25W wired charging.
Did everyone's A55 battery get worse after One UI 7?+
No. Some owners in Samsung's forums said battery life rose from two days to three after the update, so check your own top apps rather than assuming a fault.
What is the quickest check after the update?+
Wait three days on Wi-Fi and the charger, update the app at the top of Settings, Battery, and only then run the battery test.
What does Adaptive battery do on the A55?+
It learns which apps you use and limits background activity for the rest. After a big update it can take a few days to relearn, which is why Samsung-forum owners saw drain at first.
Should I turn off 5G?+
Only as a test. Compare a day on Wi-Fi or LTE with a day on 5G; if the gap is large, the radio is the cost and Wi-Fi at home solves it.
How is the Galaxy A55's battery different from the A35's?+
Both carry 5,000 mAh cells and 25 W charging, but the A55 uses the Exynos 1480 chip and a metal frame, so the same One UI settings help on both while the A55 tends to run a little cooler under load.
Does the A55's 120 Hz screen matter for battery life?+
Yes. Motion smoothness set to Standard holds 60 Hz and returns a visible share of the day, which is the first setting to try if the A55 drains faster than you expect.