The Truth About Fast Charging: Why Your Device Controls the Speed
Many users mistakenly believe that as long as they have a high-power fast charger, such as 65W, 100W or 240W, they can charge their phones instantly. However, this is not the case. The real "black hand" that determines the charging speed is your device, not the charger.
In this article, we will deeply reveal why the device side is the controller of the charging speed, and introduce the role of fast charging protocols such as PD and PPS in actual charging, to help you understand fast charging technology more scientifically.
Why Your Phone Controls the Charging Speed
Every modern smart device (especially iPhone and Samsung) has a built-in battery management system (BMS), which automatically detects the current power, battery temperature, health status and other information, and "tells" the charger based on this: what protocol, voltage and current to charge the device.
This is why, even if you use a 100W GaN charger, when charging an iPhone 16, the device will only receive about 27W of power.
📌 Key factors affecting charging speed:
·Battery temperature: Too high or too low temperature will reduce the power received by the device.
·Battery power status: 0%~50% charging is the fastest, and the device starts to actively "slow down" when it exceeds 80%.
·Device identification protocol: For example, devices that support PD 3.0, PPS, or only support ordinary 5V 2A.
·Data cable quality: Whether the cable supports high-speed current transmission is also critical.
Charger Types: GaN, PD, and PPS Explained
In order to better adapt to the control requirements of different devices, high-quality fast-charge chargers use advanced protocols and designs:
| Type | Features | Smart Collaborative Device? |
| Gan Charger | High energy efficiency, small size, can provide 65w - 240w power | ✔ Support multiple protocols |
| PD Charger | USB Power Dellivery protocol, mainstream standard | ✔ Dynamic voltage adjustment |
| PPS Charger | Programmable Power Supply protocl, can finely adjust voltage/current | ✔ Adapt to Samsung，etc. |
👉 PPS vs PD Charger, what is the difference?
Real-World Example: iPhone vs Samsung
· iPhone 15/16: Use original 35W or third-party PD fast charging, only accept about 27W, and the power is reduced when it exceeds 80%.
· Samsung S24 Ultra: Support PPS protocol, 45W full-speed fast charging. But when the battery temperature exceeds 35℃, it will automatically reduce to 25~30W.
This shows that the fast charging charger is only a "provider", and the real "controller" is your device itself.
Why Quality Chargers Still Matter
Although the device controls the charging rate, it does not mean that the charger is not important. High-quality chargers can guarantee:
· More stable voltage and current output (protect battery life)
· Wider protocol support (compatible with multiple devices such as iPhone, Samsung, Xiaomi, etc.)
· Stronger temperature control and protection mechanism (prevent overheating/overcharging/overvoltage)
Especially users in the European and Korean markets have higher and higher requirements for charging safety and efficiency. As an OEM charger factory, ZONSAN provides high-quality fast charging solutions that meet CE and KC certifications.
Conclusion: It’s a Smart Dance
The essence of fast charging is an intelligent “cooperative dance” between the device and the charger—the device guides the rhythm, and the charger cooperates to supply energy.
✅ Choose a high-quality PD/PPS/GaN charger to ensure that the device charges at the most appropriate rate, which can not only improve efficiency but also extend battery life.
📌 More recommended readings:
·What to do if Apple fast charging does not work?
·Is it safe to charge iPhone 16 at 35W?
·Why does the iPhone get hot when charging?
🔍Fast Charging FAQ
❓1. Why can't my fast charging charger reach the rated power?
This is because your phone or device will actively control the charging speed according to the current battery temperature, power level, and battery health to protect the battery safety.
❓2. Will using a high-power charger (such as 65W, 100W) damage the phone?
No. Modern devices are equipped with a power management system that will only receive the maximum power it can withstand. Using a high-quality PD/PPS/GaN charger can improve charging efficiency and safety.
❓3. Is it safe to use a 35W or 65W charger for iPhone?
Completely safe. For example, the actual maximum fast charging power of iPhone 16 is about 27W, and the device will automatically control the power to avoid overheating and overcharging.
❓4. What is the difference between PPS and PD fast charging protocols?
PPS (Programmable Power Supply) is more sophisticated than PD, can dynamically adjust voltage and current, and is more suitable for devices such as Samsung and Xiaomi. For a detailed explanation, please refer to: Differences between PPS and PD Charger
❓5. Why does my phone charge significantly slower when it is above 80%?
In order to protect the battery life, the device will automatically enter "trickle charging mode" to reduce power to prevent overheating and lithium battery loss.
❓1. Why can't my fast charging charger reach the rated power?
This is because your phone or device will actively control the charging speed according to the current battery temperature, power level, and battery health to protect the battery safety.
❓2. Will using a high-power charger (such as 65W, 100W) damage the phone?
No. Modern devices are equipped with a power management system that will only receive the maximum power it can withstand. Using a high-quality PD/PPS/GaN charger can improve charging efficiency and safety.
❓3. Is it safe to use a 35W or 65W charger for iPhone?
Completely safe. For example, the actual maximum fast charging power of iPhone 16 is about 27W, and the device will automatically control the power to avoid overheating and overcharging.
❓4. What is the difference between PPS and PD fast charging protocols?
PPS (Programmable Power Supply) is more sophisticated than PD, can dynamically adjust voltage and current, and is more suitable for devices such as Samsung and Xiaomi. For a detailed explanation, please refer to: Differences between PPS and PD Charger
❓5. Why does my phone charge significantly slower when it is above 80%?
In order to protect the battery life, the device will automatically enter "trickle charging mode" to reduce power to prevent overheating and lithium battery loss.