Leaving a 2020 MacBook Air (and any device with a lithium-ion battery) uncharged for an extended period can be detrimental to its battery health and can eventually lead to failure.
Here's a breakdown of the key reasons:
- Deep Discharge and Irreversibility:
- Lithium-ion batteries, when fully discharged and left in that state, can enter a deep discharge state.
- In deep discharge, the battery's voltage drops below a critical point, and its internal chemistry can undergo irreversible changes, making it incapable of holding a charge. This means the battery may no longer respond to charging and essentially becomes unusable.
- Self-Discharge:
- All batteries, including lithium-ion, experience a gradual loss of charge over time, even when not in use. This is known as self-discharge.
- While the self-discharge rate for lithium-ion batteries is relatively low compared to older battery technologies, it can still lead to a deep discharge if left unattended for a prolonged period.
- Chemical Degradation:
- Lithium-ion batteries naturally degrade over time, a process called calendar aging, even if not actively used or cycled.
- This degradation involves unavoidable chemical side reactions within the battery's components, leading to a reduction in its capacity.
- If the battery remains uncharged for a long time, these degradation processes can be exacerbated, further contributing to capacity loss and potential failure.
Apple's recommendations for long-term storage
- Charge to around 50%: Do not fully charge or fully discharge the battery.
- Power down the device: Avoid additional battery use.
- Store in a cool, moisture-free environment: Ideally, less than 90° F (32° C).
- Recharge to 50% every six months: If storing for longer than six months.
By following these recommendations, you can help minimize the risk of battery failure when storing your MacBook Air for extended periods.