Now all kinds of mobile power supply on the market, in the selection of mobile power supply, in addition to compare its appearance and portability, is often compared to the mobile power parameters. So, what are the main performance parameters of mobile power worthy of note?
Capacity (mAh): charging battery are ma (mAh), is the product of current intensity and time, when Ma with current intensity (mA) as a unit, time in hours (H) unit, the two of them multiplication is ma (mAh). The expressed complete discharge in the discharge current under the certain time, for example, 1000 MAH refers to the battery can discharge 1 hours at a current of 1000 Ma under.
Mobile power supply capacity division did not differentiate too strict, general mobile power supply capacity of around 1000mAh-12000mAh, taking into account the mainstream smart mobile phone battery capacity in general about 2000mAh (Samsung i9300 battery capacity is 2100mAh), so we will move power supply according to the volume is divided into the following 2000mAh (one-time charge, in consideration of portability), 2000-5000mAh (energy to charge a mobile phone 1-2 (mobile phone), 5000mAh-10000mAh can give multiple charging, or to charge a flat computer) and 10000mAh (multi department charging equipment to more than four grade).
We also want to point out, for the mobile power supply, and the capacity is not the bigger the better, after all, the capacity is only a can be measured using the time parameter. At the time of purchase, should be based on their habits and the actual demand to choose, should not blind pursuit "of large capacity".
Also worth noting is the capacity of mobile power supply, generally refers to the manufacturers in product packaging marked on the capacity value, the capacity value usually refers to mobile power supply inside the electric core capacity value, while the actual used capacity than many consumers feel that the value of.
The output voltage (V): imitation USB interface of a computer and mobile phone charger, usually 5V;
Output current (mA): at present the output current standards than common 500mA, 1000mA (1A) and 2100mA (2.1A) etc.. The former two generally used to charge the mobile phone, the latter is common in large capacity mobile power for the tablet computer charging. And the same capacity, output current is the choice of an important indicator to consider mobile power supply. This is because, under the same pressure, and the current is charging equipment nominal parameters more similar to make the charging process more efficient.
The input voltage (V): imitation USB interface of a computer and mobile phone charger, usually 5V;
The input current (mA): similar mobile power output current directly affect the charging efficiency of digital products, mobile power supply input current will be on charging efficiency of mobile power directly influence. For example, mobile power of a 12000mAh, if the rated input current is only 500mA, which means that the full power of the time required to move up to more than 20 hours; but if the rated current is 2.1A, then only need about 7 hours or so, that is to sleep at night time will be full of.
The conversion rate (%): informally, mobile power conversion rate conversion efficiency is the core of mobile power internal electric charge and discharge time. For example, in theory, a 5000mAh mobile power supply, if the 5V/1A constant current source charging it, 5 hours can be filled, but in fact it is impossible to. This is because both the mobile power supply inside the electric core and the protection board, power supply interface, in the process of charge and discharge will have a certain loss, including: circuit switching loss; its operating loss; boost consumption.
The loss is caused by boosting we feel "why mobile power supply capacity is not our imagination of so big" reason. Lithium battery electric core discharge voltage of mobile power supply adopted in general about 3.7V-4.2V, while the standard input voltage digital products such as mobile phone is 5V, so the mobile power supply needs through the booster circuit internal, voltage output 5V for mobile phone charging, which will be lost.
In simple terms, the so-called "capacity" is only representative of discharge capacity in the nominal output voltage and current under the specified mobile power supply, and not the real energy truly representative of mobile power supply. Battery energy in kWh (Wh) as the unit, as the capacity (mAh) and rated voltage (V) of the product, such as mobile power of a 5000mAh, here's capacity for lithium battery electric core capacity, rated voltage of 3.7V, so the energy should be 5000mAh*3.7V/1000=18.5Wh, but if 5V after boosting voltage the output, the effective output charge is 18.5Wh/5V*1000=3700mAh, this is what we can find is in use, a nominal 5000mAh mobile power supply, but may not be able to give a 1440mAh iPhone 5 with three electrical reasons.
The conversion efficiency of the electric core directly determines the quality of mobile power supply. In general, the discharge of imported electric core conversion rate is 85%, the domestic A product is about 75%-85%.
More than just can help the user to choose some of the main performance parameters of mobile power supply, but mobile power market uneven, some good and some bad, virtual standard capacity, parameters of such phenomena emerge in an endless stream, at the time of purchase should not only pay attention to the parameter, more attention should be paid to the use of reference of others experience.