Caring for Rechargeable Batteries So They Last Longer

Tech & Devices Editorial Team Staff Writer · Jul 23, 2023 · 5 min read

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Practical habits for preserving battery health in phones, earbuds, laptops, and other rechargeable devices you use every day.

Key Takeaways

Keeping lithium-ion batteries between 20% and 80% charge preserves their long-term capacity.
Heat is the single biggest enemy of rechargeable battery health — avoid hot environments during charging.
Enabling built-in battery optimization features on phones and laptops can meaningfully slow capacity loss.
Partial charges are generally healthier for lithium-ion batteries than full discharge cycles.
Storage habits matter: devices kept at extreme charge levels for weeks degrade faster.

Why Battery Care Actually Matters

Most rechargeable devices — phones, earbuds, laptops, tablets — use lithium-ion (Li-ion) batteries. These batteries have a finite number of charge cycles before their capacity noticeably declines. A charge cycle is roughly one full discharge and recharge, though partial charges count proportionally. Most Li-ion batteries are rated for 300 to 500 full cycles before dropping to about 80% of their original capacity.

The good news is that a battery's rated cycle count assumes average usage. Habits that reduce heat, avoid extreme charge levels, and limit unnecessary full discharges can extend useful battery life well beyond the manufacturer's baseline estimate. For context on how batteries fit into overall device longevity, see our article on what actually determines how long a device lasts.

Best Practices for Preserving Battery Health

The following practices apply broadly to phones, laptops, wireless earbuds, and similar Li-ion powered devices.

Keep your battery charge between 20% and 80% as a general rule.

Li-ion batteries experience the least chemical stress in the middle of their charge range. Regularly charging to 100% or letting the battery drain to 0% accelerates the chemical degradation that reduces capacity over time.

Example: Setting your phone to stop charging at 80% — a feature available in many device settings — means the battery rarely sits at peak voltage stress overnight.

Avoid exposing charged devices to high heat.

Heat accelerates the chemical reactions inside Li-ion cells that permanently reduce capacity. This is true whether the heat comes from direct sunlight, a hot car interior, or a warm surface during charging.

Example: Charging your phone on a hard, ventilated surface in a shaded area — rather than on a car dashboard in summer — keeps operating temperatures lower during the charge cycle.

Use the charging speed appropriate to your situation.

Fast or rapid charging is convenient but generates more heat, which contributes to faster cell degradation when used as the default every day. Slower charging produces less heat and is gentler on the battery.

Example: Reserving fast charging for when you genuinely need a quick top-up, and using a standard charger overnight or when time allows, balances convenience with battery longevity.

Enable your device's built-in battery optimization settings.

Operating systems on modern phones and laptops include algorithms that reduce how long a battery sits at 100% charge — a state that accelerates aging. These settings are often disabled by default.

Example: On a MacBook used primarily at a desk, enabling the 'Optimized Battery Charging' setting in System Settings can meaningfully slow long-term capacity decline.

Avoid full discharges unless the device requests a calibration.

Deep discharges — running a Li-ion battery all the way to zero — put more stress on the cells than partial discharges. Modern devices rarely need full discharge cycles for calibration, making them largely avoidable.

Example: Plugging in your earbuds at 30% rather than waiting until the low-battery warning sounds is better for the small, hard-to-replace Li-ion cells inside.

Charging Smarter Every Day

Most modern devices include software tools designed to slow battery aging — but they only help if you use them. On iPhones, Optimized Battery Charging learns your routine and pauses charging at 80% until shortly before you typically unplug. Android devices from several manufacturers offer similar scheduled or limited charging modes. Laptops from major manufacturers increasingly include settings to cap charging at 80% for devices that spend most of their time plugged in.

Use Software Limits Before You Buy Accessories

Before purchasing third-party battery accessories, explore your device's native software first. Many phones and laptops already include charge scheduling, charge caps, and health reporting tools that are free and well-integrated. Third-party apps claiming to 'optimize' batteries often provide little benefit that the operating system doesn't already handle.

Wireless charging generates more heat than wired charging, which can contribute to slightly faster capacity loss over time. Our comparison of wired and wireless charging covers the real-world tradeoffs in more detail. Also, if you've heard that overnight charging damages batteries, the evidence is more nuanced than the common claim suggests.

high Open your phone's battery settings today and enable any available charging optimization or charge limit feature.

medium Move your phone off its wireless charging pad once it reaches 80%, or set a charging schedule if your device supports it.

high Stop leaving your laptop plugged in at 100% all day — either set a charge cap in your power settings or unplug once it's sufficiently charged.

medium Charge your devices in a cool, ventilated spot rather than on a bed, couch, or in direct sunlight.

Storage and Long-Term Care

If you're setting a device aside for weeks or months — a backup phone, a seasonal gadget, a spare laptop — the charge level you store it at matters.

Ideal Storage Charge Level

Battery researchers generally recommend storing Li-ion devices at around 50% charge if they'll be unused for an extended period. Storing at full charge keeps the cells at high voltage stress; storing at 0% risks the battery dropping below a safe minimum threshold. A quick partial charge every few months during storage helps maintain cell health.

Charging safety is also worth keeping in mind. Using chargers and cables designed for your device, avoiding covered or enclosed spaces while charging, and not charging on soft surfaces like pillows reduces both heat buildup and fire risk. Our guide to using gadgets safely at home covers these considerations in full. Battery care for Li-ion devices differs meaningfully from lead-acid car batteries; for the latter, see our separate piece on car battery health.

~80%

Capacity retained after 500 full charge cycles

Li-ion battery specifications from major device manufacturers commonly cite 80% capacity retention at 500 cycles under standard conditions.

20°C–25°C

Optimal operating temperature range for Li-ion batteries

Battery research consistently identifies moderate room temperature as the range that minimizes stress and maximizes the useful life of lithium-ion cells.

Tech & Devices Editorial Team

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