What Was Happening
A customer from Wimbledon SW19 brought in a MacBook Pro 13-inch 2016 (A1708) following a macOS notification advising them to service the battery. The machine was discharging unusually quickly — where it had previously lasted a full working day on a charge, it was now reaching 20% battery within a couple of hours. The customer had also noticed the machine rocking slightly on their desk, which it had not done before.
The machine was otherwise performing well — the customer used it daily for work and the hardware was in good general condition.
Our Diagnosis
Battery condition check in macOS System Information showed the battery at 52% of its original design capacity, with a cycle count of 847. Apple’s service threshold triggers the warning at 80% capacity; at 52%, the battery was well past that point.
Physical inspection confirmed swelling — the base panel had a slight bow at the centre, consistent with the battery expanding beneath it. On the A1708, the battery sits directly beneath the trackpad and the centre of the chassis. Swelling at this stage had not yet affected the trackpad function, but the bow in the panel was visible and the swelling would continue to progress if the battery was not replaced.
We also confirmed the trackpad was responding correctly across its full surface — no click resistance or dead zones — which meant the swelling had not yet reached the point of mechanical interference.
How We Fixed It
Battery swelling requires careful handling. The A1708 battery is adhesive-bonded to the chassis rather than screwed in — it cannot be levered out without risk of puncturing the swollen cell. We used approved depressurisation and adhesive-release techniques to remove the battery safely before fitting the replacement.
The replacement battery was fitted and secured. Before reassembly, we confirmed the base panel seated flat against the chassis — confirming the new battery was not over-thickness. The machine was assembled and tested: battery charging confirmed, cycle count reset, macOS System Information showing the battery as in normal condition.
The Result
The MacBook Pro was returned to the Wimbledon customer the same day. The Service Recommended warning had cleared. Battery life at full charge was testing at approximately 7–8 hours under typical use — consistent with a new battery on this generation. The base panel was sitting flat.
The 2015–2019 MacBook Pro Battery Pattern
The thin, flat battery design used in the 2015–2019 MacBook Pro range was an engineering compromise to achieve the slim chassis profile. The cells in these batteries degrade in a pattern that produces swelling in a meaningful proportion of units — the A1502, A1706, A1708, A1989, and A2159 all share this characteristic.
Apple ran a battery replacement programme for the 2015 13-inch MacBook Pro following acknowledgement of this pattern, but the affected range extends across the adjacent years. Machines from this generation that are used regularly and are approaching 5–7 years of age are worth monitoring for the battery bow symptom. The visible signal — a base panel that rocks — appears before the trackpad interference that indicates the swelling has progressed to a more urgent stage.
Prevention Tips
- Check macOS Battery Health status periodically: System Settings → Battery → Battery Health
- If the base of your MacBook Pro rocks on a flat surface and it didn’t used to, have the battery inspected — this is the earliest visible sign of swelling
- Using battery management features (macOS 10.15.5 and later offers optimised charging) reduces the number of charge cycles and can slow degradation over time
Local Help in Wimbledon SW19
We carry out MacBook battery replacements at our Putney workshop for customers across Wimbledon SW19 and SW20. Free collection is available — about 12–18 minutes from Putney via the A3.
Related Services
- MacBook Repair — battery and hardware repairs for all MacBook models
- MacBook Repair in Wimbledon — local service for SW19 and SW20
More Case Studies
- MacBook Pro battery swelling repair in Putney — same fault pattern on the adjacent generation
- MacBook Air upgrade to latest macOS in Putney — software service extending another aging MacBook’s life
- MacBook Pro keyboard liquid damage repair in Wandsworth — another MacBook repair from a nearby area