Owners of the popular Xiaomi Redmi Note 5 smartphone (known in China as the Redmi Note 5 Pro) often face the need to replace or purchase an additional charger. This can be due to the loss of the original power supply, its breakdown or the desire to speed up the process of replenishment of energy.
Launched in 2018, this model is based on the Qualcomm Snapdragon 636 processor, which has a built-in power controller, which dictates the conditions under which the device will work most efficiently. In this article, we will discuss in detail the technical requirements, supported fast charging protocols and give recommendations for choosing a safe accessory for your smartphone.
Technical characteristics of the battery
At the heart of a smartphone's power system is a non-removable lithium polymer battery, which has a capacity of 4,000 mAh, which was considered a great measure of autonomy for its time, but to get the charger right, you have to consider not only the capacity, but also the rated voltage of the cell, which is usually 3.85 volts.
The power controller integrated into the motherboard tightly regulates the incoming current. It converts the voltage from the mains (220V) through the power supply to battery-safe values. If you use an adapter that is too weak, the charge process will take an indefinite time, and if it is too powerful and protocol-incompatible, the system will simply limit the current to standard values.
Why is the compatibility of the controller important?
It is worth noting that over time, battery capacity naturally degrades. Using low-quality chargers with unstable output voltage can speed up this process, so you should pay attention to the availability of quality certificates and well-known brands when choosing an accessory.
Supported fast charging protocols
A key feature of the Xiaomi Redmi Note 5 is Qualcomm’s Quick Charge 3.0 technology, which significantly reduces energy recovery time compared to conventional charging, and works by dynamically changing voltages in the range of 3.2 to 20 volts in 200 mV increments.
Beyond the QC 3.0, the device is fully compatible with earlier versions of the standard, such as Quick Charge 2.0.This means you can use older power supplies from flagship smartphones of yesteryear, and they will work correctly, albeit with less efficiency.However, backwards compatibility does not always guarantee top speed.
- 🔌 Quick Charge 3.0: Main supported standard that provides maximum charge speed to 18-20 Watt.
- ⚡ Quick Charge 2.0: Fully compatible predecessor, running consistently but slower.
- 📉 Standard Charging: Regular Charging 5V/2A or 5V/1A. If the power supply does not support acceleration protocols.
⚠️ Attention: Protocol VOOC (The smartphone used in Oppo and OnePlus or SuperCharge (Huawei) will not work in fast charging mode on the Redmi Note 5. the smartphone will charge in normal mode, as these technologies are proprietary and incompatible with the Snapdragon chipset.
It’s important to understand the difference between the power of the power supply and the actual power the phone receives. Even if you plug the device into a 65-watt unit, the Redmi Note 5 will take just as much as its controller allows — about 18 watts.
Recommended charging device parameters
When choosing a new power adapter, you need to focus on the specific digital values indicated on the product body. The optimal option for the Xiaomi Redmi Note 5 is a unit with output parameters 5V/2A or 9V/2A. These values provide a balance between speed and safety.
Current is critical. If the power supply is less than 1 Ampere (500 mA), charging will be extremely slow, and when you use the screen, the phone may even run out despite being connected to the network. The minimum comfortable threshold is 1.5 Ampere.
Also worth paying attention to the build quality of the USB connector itself. Cheap Chinese adapters often have a backlash in the port, resulting in poor contact and periodic interruption of charge.
Full charge time and real speed
Users are often wondering how long it takes to complete a charging cycle. Using the original Quick Charge 3.0 adapter and quality cable, the 4,000mAh battery charges in about 2 hours and 15 minutes to 100%.
If you use a standard 5B/2A charger without acceleration protocols, the time will increase to 2 hours 45 minutes – 3 hours. The difference may seem small, but it is significant if you need to urgently recharge for 30-40 minutes.
| Type of charger | Time to 50% | Time to 100% | Maximum power |
|---|---|---|---|
| Quick Charge 3.0 (18W) | ~45 minutes | ~2h 15 min | 18 W. |
| Standard 5B/2A | ~60 minutes | ~2h 50 min | 10 Watts. |
| Weak charging 5V/1A | ~90 minutes | ~4h 30 min | 5 watts |
| USB port of the computer | ~100 minutes | ~5h 00 min | 2.5 W. |
It is worth considering that the latter 10-15% It's a normal algorithm for lithium batteries to prevent overcharging and overheating.
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For maximum charge speed during use of Quick Charge, it is recommended to turn off the screen of the smartphone. Active operation of the display and applications heats the case, forcing the controller to reduce current to avoid overheating.
Requirements for USB-cable
Often the problem with slow charging is not the power supply, but the cable. To realize the potential of Quick Charge 3.0, you need a cable that can pass current of 2 Amps. Thin and cheap cables have high resistance, which leads to a voltage drop and loss of power.
Pay attention to the labeling of the cable. Quality conductors are often labeled 3A or QC 3.0 on the plug or package. The length of the cable also matters: the longer it is, the greater the voltage loss, so cables up to 1 meter long are optimal for fast charging.
- 🔍 Visual inspection: The cable should not be too thin, high-quality insulation and dense connectors are signs of a good product.
- 📏 Length: Use cables 1 meter long for charging and up to 2 meters only if needed, but with loss of speed.
- 🛡️ Protection: Kevlar-plated cables last longer and conduct current better than cheap plastic counterparts.
⚠️ Warning: A damaged cable with rubbed insulation or broken at the plug may cause a short circuit.If charging is only done at a certain position of the cable in the socket, replace the accessory immediately.
Using the original Xiaomi cable or certified analogues from brands like Ugreen, Baseus or Anker guarantees stable data and energy transfer without voltage surges.
Safety and operational advice
Modern smartphones, including the Redmi Note 5, are equipped with a protection system. However, the user must also follow basic rules of operation. Do not leave the device to charge on a soft surface (bed, sofa), as this violates the heat sink and can lead to overheating of the battery.
Temperature is critical for lithium polymer batteries; charging at temperatures below 0°C or above 45°C can cause irreparable damage to the battery chemistry; the controller can block charging at extreme values.
☑️ Checking the safety of charging
If you notice that the phone is charging in jerks, spontaneously shuts down or heats up in the area of the charging port, this may indicate a malfunction of the power controller or contamination of the connector.
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The main conclusion: For the Redmi Note 5, any high-quality power supply with Quick Charge 3.0 support and output current from 2A is ideal. Using more powerful adapters is safe, but will not speed up charging.