Is Fast Charging Killing the Battery? A 2-Year Test on 40 Phones

Summary

In this comprehensive experiment, we test how fast charging, slow charging, and battery health affect the performance and longevity of phone batteries. Using multiple iPhone 12s and Android devices, we simulate real-world charging conditions, including cycles, battery wear, and different charging speeds. The results show minimal differences between fast and slow charging, with slight advantages in keeping battery levels between 30% and 80%. While battery wear does impact battery life, it doesn’t significantly affect performance until the health drops below 80%. The video aims to debunk myths about battery care and offers practical insights on phone maintenance.

Takeaways

• 😀 Fast charging doesn't significantly harm the battery more than slow charging. After 500 cycles, the difference in capacity loss between the two methods is minimal.
• 😀 Charging your phone overnight with a slow charger won’t necessarily prevent battery damage, as the difference between slow and fast charging in terms of battery wear is very small.
• 😀 Keeping your battery between 30% and 80% can help reduce wear, but the effect is limited. The 50% fast-charge group showed less battery capacity loss than the full fast-charge group.
• 😀 Charging habits like leaving your phone plugged in at 100% won’t cause significant damage to the battery. Apple’s warnings about storing a phone at full charge for long periods are precautionary but not drastic.
• 😀 Battery aging is a gradual process, and even phones that went through 500 charge cycles (approximately 1.5 years of use) showed minimal capacity loss (less than 0.5% difference).
• 😀 Once your battery health drops below 85%, you may notice a reduction in battery life. When it falls near 80%, it's time to replace the battery.
• 😀 A degraded battery doesn't necessarily slow down your phone's performance, but it does cause earlier throttling, especially when battery health drops below 85%.
• 😀 Replacing a battery that has degraded around 85% or lower significantly improves performance and battery life, as seen in tests where new batteries increased battery life by 6% to 24%.
• 😀 The test used iPhones and Androids (iQOO 7) with both fast and slow charging conditions to ensure the results are independent and reproducible. It took around six months to complete.
• 😀 The emotional attachment to ‘caring’ for a phone by following charging habits like waiting until the battery is below 20% or charging to 100% didn’t actually benefit the phone, but it provided peace of mind to users.

Q & A

Does fast charging really damage your phone's battery?

Based on the experiment, fast charging caused only a slight increase in battery wear compared to slow charging. After 500 cycles, the fast-charge group showed a loss of 12.3% of capacity, while the slow-charge group lost 11.8%. The difference was minimal, indicating that fast charging doesn't significantly harm the battery in the long term.

What is the healthiest charging range for a phone battery?

The experiment tested a group of phones that charged between 30% and 80%. This group showed less capacity loss compared to the full fast-charge group, but the improvement was limited. Keeping the battery between 30% and 80% can reduce wear, but the effect is not drastic over the long term.

Does battery wear make your phone slower?

Battery wear itself doesn't noticeably affect the phone's performance. However, phones with degraded batteries tend to throttle their performance earlier. For example, an iPhone with 85% battery health starts throttling at 11%, while a new battery doesn't throttle until 5%. This can result in slightly better performance with a new battery.

When should I replace my phone's battery?

Once the battery health drops below 85%, you'll begin noticing shorter battery life. When it approaches 80%, it’s generally a good idea to replace the battery to avoid performance throttling and ensure optimal battery life.

Does keeping your phone plugged in at 100% damage the battery?

The experiment tested phones left plugged in at 100% and found that the battery capacity did not change after a week. While it is true that prolonged storage at full charge can cause some battery wear over time, keeping your phone plugged in at 100% doesn’t cause immediate noticeable damage.

How much does battery health impact daily phone use?

As the battery health drops, you may notice shorter battery life during daily use. For example, phones with 85% battery health had a 6% increase in battery life after replacing the battery, while phones with 77% battery health saw up to a 24% improvement after battery replacement.

What factors influence battery wear the most?

The most significant factors for battery wear include how often you charge, whether you use fast charging, and how low or high your battery level drops before charging. However, the effects are minimal over the course of typical usage, with battery wear only becoming noticeable after a significant number of charge cycles.

Is it better to use a slow charger over a fast charger for battery health?

The experiment showed only a very slight difference in battery wear between fast charging and slow charging. The fast-charge group showed 0.5% more capacity loss than the slow-charge group over 500 cycles. Therefore, using a slow charger is not drastically better for the battery, though it might result in marginally less wear over time.

How does battery wear affect gaming performance?

As the battery health decreases, the phone may throttle performance earlier. In games, this means that a phone with a new battery can continue to run games longer before slowing down. For example, a phone with 85% battery health starts throttling performance at 11%, while a new battery doesn’t throttle until 5%.

Does using your phone while charging affect the battery?

This question is addressed in another experiment by the creators. Generally, using your phone while charging doesn't cause significant harm to the battery, though it can cause the phone to heat up, which may affect battery longevity over time. The main concern is how much the phone heats up during the process.