Every iPhone reports two battery numbers, and bulk buyers routinely treat them as one. They measure different things: one describes condition, the other describes history. A lot can look strong on one number and weak on the other, and that gap is where grading disputes start.
Battery health, shown as Maximum Capacity, is a percentage. It compares the charge a full battery holds today with the capacity it held when new. A reading of 88% means the cell is holding roughly 88% of its original capacity.
Cycle count is cumulative use. One cycle is 100% of discharge, however it was accumulated, so two half-charges add a single cycle. Health is a condition reading; cycles are a usage history reading.
Neither number is a runtime measurement. Both are indicators that you still have to test in practice.
When readings look contradictory, the pattern usually points at a cause. These four cover most of what shows up in mixed lots:
| Pattern | What you see | Likely explanation | Buying implication |
|---|---|---|---|
| Aged cell, light use | Health below 85%, cycles under 300 | Calendar ageing, heat exposure, long storage at full charge | Grade on health; test real runtime |
| Heavy but gentle use | Health 90%+, cycles over 700 | Many shallow top-ups, little deep discharge or heat | Usually genuine; confirm runtime matches |
| Fresh readings on an old unit | Health near 100%, cycles near zero | Battery replaced, or service board replaced during a repair | Ask for service history; price the risk |
| Implausible pairing | Health normal, cycles odd for the model age | Counter travelled with the part that was swapped | Cross-check the two numbers together |
A cycle is not "one charge". Discharge 60% today and 40% tomorrow and the counter logs one full cycle. That is why a device used in short top-ups can carry a high cycle count with a cell that still tests well.
Apple rates its batteries by cycles to 80% capacity. As published by Apple, iPhone 14 and earlier are designed to retain 80% of capacity at 500 complete cycles, while iPhone 15 and later are rated at 1000 cycles.
The practical consequence: two units both sitting at 85% health do not have the same remaining life if they belong to different design generations. Always read health and cycles against the model, never against a single company-wide rule.
Because the counter lives with the battery and its management board, a replacement resets one side of the pair without touching the other. That single sentence explains most mismatches our QC team sees. The wider fault picture sits in our guide to common used iPhone defects.
| Number | Best used for | Weak at |
|---|---|---|
| Maximum Capacity | Grade language, pricing bands, return exposure | Detecting repairs or usage intensity |
| Cycle Count | Screening service history and age, spotting refurbishment | Grading on its own or predicting runtime |
Used together they answer two different questions: how much capacity is left, and how hard the unit was worked to get there. Our battery health thresholds guide covers the percentage bands; the battery grading framework covers how to write them into a grade.
A battery floor that mentions only health invites argument. State the pair and the rule for conflict:
Then decide the commercial response in advance. Units that miss the floor are either renegotiated, returned, or moved into a different channel, and battery replacement at scale is only a fix if you have already priced the parts and labour into the offer.
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