The battery life of portable power supply depends on three core factors: actual output power, battery energy capacity and equipment conversion efficiency, and is also affected by many variables such as environment and usage habits. The specific disassembly is as follows:
Energy capacity of battery (core basis)
This is the fundamental parameter that determines the upper limit of endurance, and the unit is usually Wh (watt-hour). The higher the value, the longer the theoretical endurance.
Formula reference: theoretical battery life (hours) = rated capacity of power supply (Wh)÷ actual input power of equipment (W)
Note: Some products will be marked with mAh (milliampere hour), but mAh needs to be combined with voltage to be converted into Wh, and cross-voltage comparison is meaningless.
Actual power of output device (the most direct variable)
The battery life is inversely proportional to the power of the equipment. The greater the power of the equipment, the faster the power consumption.
Low-power devices (such as mobile phones and Bluetooth headsets): power consumption is only a few watts, and the portable power supply can last for dozens of hours;
High-power equipment (such as notebook computers, car refrigerators, small household appliances): the power consumption can reach tens or even hundreds of watts, and the battery life will be greatly shortened.
In addition, when multiple devices are charged at the same time, the total output power will be superimposed and the battery life will be reduced accordingly.
Conversion efficiency of power supply itself
The electric energy stored in the battery will be lost in the process of converting it into output AC/DC, and the loss rate is usually between 10% and 30%. The lower the conversion efficiency, the shorter the actual battery life.
The loss of pure DC output (USB port) is low, generally 10% ~ 15%;
The loss of AC inverter output (AC port) is higher, especially in high-power inverter, the loss can reach 20%~30%.
Influence of ambient temperature
Lithium battery is sensitive to temperature, too high or too low environment will reduce battery activity and affect battery life;
Low temperature environment (< 0℃): the discharge capacity of the battery decreases, and the battery life may be shortened by 20%~50%, or even it cannot be output;
High temperature environment (> 40℃): The battery loss is accelerated, and at the same time, the power supply will start temperature control protection, which will limit the output power and indirectly affect the battery life.
Aging degree of power supply
Lithium batteries have a cycle life, and with the increase of charge and discharge times (generally 300~1000 cycles), the battery capacity will gradually decrease.
After aging, the actual available capacity of the power supply is lower than the nominal value, and the battery life will be shortened.
Energy consumption of extra functions
The display screen, indicator light, cooling fan and the identification and switching of fast charging protocol of the power supply will consume a small amount of electricity, and the battery life will be slightly shortened if it is turned on for a long time.
