How to Make Your Phone Battery Last Longer: 9 Habits That Actually Work

The fastest ways to make your phone battery last longer are simple: keep the charge between 20 and 80 percent where you can, turn on Optimised Battery Charging (or Battery Protection on Samsung), keep the phone out of the heat, and tame the big power drains like full screen brightness and background app refresh. Phone batteries are consumables. They lose capacity with every charge cycle, but good habits can keep a typical iPhone or Samsung battery above 80 percent health for 2 to 3 years or more. This guide walks through the habits that actually move the needle, how to check your battery health in under a minute, and what to do when the battery is already past saving.

In this article

• Why does my phone battery drain so fast?
• Should I only charge my phone to 80 percent?
• Is it bad to charge my phone overnight?
• Which settings drain the battery the most?
• Does heat damage phone batteries?
• Does fast charging ruin my battery?
• How do I check my battery health?
• What if my battery still will not last the day?
• When should I replace the phone instead?
• FAQ

Why does my phone battery drain so fast?

Every phone battery is a lithium-ion cell, and lithium-ion cells age in two ways: through charge cycles (roughly 500 full cycles before capacity drops to about 80 percent) and through stress, mainly heat and long stretches at very high or very low charge. Day to day, the biggest consumers of power are the screen, the mobile radios (especially on a weak signal, when the phone works harder to stay connected) and apps refreshing in the background. So a battery plan has two halves: reduce the daily drain, and reduce the long-term wear.

Should I only charge my phone to 80 percent?

Keeping your battery between roughly 20 and 80 percent is the single best habit for long-term battery health. Lithium-ion batteries age fastest when they sit at 100 percent for hours, a state battery engineers call high voltage stress. Charging to about 80 percent avoids the most damaging part of the curve while still giving you most of a day of use, and researchers estimate this habit alone can delay a battery replacement by a year or more.

You do not have to manage this manually. On iPhone, go to Settings, then Battery, then Charging, and set a charge limit of 80 percent (iPhone 15 and newer) or leave Optimised Battery Charging on. On Samsung, turn on Battery Protection in Settings under Battery. Both features exist precisely because the 20 to 80 rule works.

Is it bad to charge my phone overnight?

No, overnight charging will not overcharge a modern phone. Every current iPhone and Samsung stops drawing full power once the battery is full. The real issue is that the battery then sits at 100 percent for hours, which is exactly the high voltage stress described above. The fix is to leave Optimised Battery Charging or Battery Protection switched on, so the phone holds at 80 percent for most of the night and only tops up shortly before you wake. Also avoid charging under a pillow or on soft bedding, since trapped heat is worse for the battery than the charging itself, as battery researchers at The Conversation explain.

Which settings drain the battery the most?

If your phone struggles to see out the day, work through these in order. They are ranked by real-world impact:

• Screen brightness. The display is the hungriest component in the phone. Turn on auto brightness and drop the manual slider.
• Shorter auto-lock. Set the screen to lock after 30 seconds instead of 2 to 5 minutes.
• Background App Refresh. Turn it off for apps you do not need updating silently (social media apps are the worst offenders).
• Location services. Set apps to "While Using" instead of "Always".
• Weak signal areas. If you are somewhere with poor reception and do not need data, flick on aeroplane mode or connect to Wi-Fi, which uses far less power than a straining 4G or 5G connection.
• Dark mode. On OLED phones (iPhone X and later, most Samsung Galaxy models) dark mode gives a modest but genuine saving because black pixels are switched off.
• Low Power Mode. When you need the phone to simply survive, Low Power Mode (iPhone) or Power Saving (Samsung) cuts background activity and can stretch the remaining charge by hours.

Does heat damage phone batteries?

Yes, and permanently. Apple warns that ambient temperatures above 35 degrees Celsius can permanently reduce battery capacity, which matters in an Australian summer. The worst offenders are leaving the phone on a car dashboard, in a parked car, or in direct sun at the beach. Heat plus charging is the most damaging combination of all, so if the phone gets hot while fast charging or wireless charging, take the case off or move it somewhere cooler. A battery damaged by heat never recovers that capacity.

Does fast charging ruin my battery?

Not when you use a quality charger. Fast charging generates a little more heat than slow charging, but phones manage this by charging quickly only up to about 80 percent, then trickling the rest. The thing to avoid is cheap, uncertified chargers with poor voltage regulation. A certified GaN (gallium nitride) charger runs cooler and more efficiently than older chargers, and one good multi-port unit can replace the drawer full of adapters.

How do I check my battery health?

On iPhone, open Settings, tap Battery, then Battery Health and Charging, and read the Maximum Capacity percentage. On Samsung, open the Samsung Members app and run a battery diagnostic, or check Settings, then Battery, then Battery Information on newer models. Here is what the number means:

Battery health	What it means	What to do
90 to 100%	Effectively like new	Keep the good habits going
80 to 89%	Normal wear, still solid all-day use	No action needed; a power bank covers heavy days
Below 80%	Noticeably shorter days, possible slowdowns	Consider a battery replacement or a phone upgrade

The 80 percent line matters because that is the industry benchmark for a serviceable battery. It is also why every refurbished phone at OZ Tech Deals is tested to a minimum of 80 percent battery health before sale.

What if my battery still will not last the day?

Some days no setting will save you: festivals, flights, long commutes, or an older battery doing its best. A magnetic power bank is the cheapest fix. It snaps to the back of a MagSafe compatible iPhone (or any phone with a magnetic case) and tops you up while you keep using the phone, no cable required.

If you would rather have raw capacity than slimness, a 10,000mAh bank will fully recharge most phones twice:

Here is how the two compare at a glance:

	Baseus PicoGo AM41	CHOETECH PowerLeap
Capacity	5,000mAh (about one full top-up)	10,000mAh (about two full charges)
Charging style	Magnetic 15W wireless, snaps to the phone	35W wired via built-in USB-C cable
Best for	Everyday carry, MagSafe iPhones	Travel, festivals, any phone or tablet
Price	$69.95 AUD	$76.95 AUD

Not sure whether your phone supports magnetic charging? Our guide to MagSafe and Qi2 accessories explains it in plain English.

When should I replace the phone instead?

If your battery health is under 80 percent and the phone is more than 3 to 4 years old, weigh up the numbers. A battery replacement typically costs $100 to $180 in Australia, and on an ageing phone it fixes the battery but not the slowing chip, dated camera or looming end of software updates. A refurbished phone often makes more sense: every device at OZ Tech Deals is tested to a minimum of 80 percent battery health and backed by a 24-month warranty on the device plus a 12-month warranty on the battery. Read our refurbished iPhone buying guide for the full checklist.

Frequently asked questions

Does dark mode really save battery?

Yes, on phones with OLED screens (iPhone X and later, most Samsung Galaxy models). OLED displays switch black pixels off entirely, so dark mode gives a modest but real saving, especially at higher brightness. On older LCD phones it makes almost no difference.

Is it bad to let my phone battery drop to 0 percent?

Regularly running the battery flat adds wear, because deep discharges stress lithium-ion cells much like sitting at 100 percent does. The occasional flat battery will not kill your phone, but as a habit, plug in at around 20 percent.

Does closing background apps save battery?

No, and it can actually use more power. Swiping apps away forces the phone to reload them fully next time, which costs more energy than resuming a suspended app. Manage Background App Refresh in settings instead.

How long should a phone battery last before it needs replacing?

Most phone batteries retain about 80 percent of their capacity after 500 full charge cycles, which works out to roughly 2 to 3 years of typical use. Good charging habits and avoiding heat can stretch that noticeably further.

What battery health is considered bad?

Below 80 percent maximum capacity is the accepted benchmark for a worn battery. At that point you will notice shorter days and, on iPhone, possible performance management kicking in. That is also why refurbished sellers worth buying from test batteries to a minimum of 80 percent health.