How Can We Know If the Customized Portable Power banks Mobile Chargers Is Real Capacity As Its Marked information:

Power Banks can be considered as lifesavers as they power our precious devices while we’re on the move. An efficient charger can quickly charge electronic devices, ensuring that users can go about their business as usual. Your target audience can use our promotional power banks to charge cell phones, tablets, laptops, MP3 players and other electronic devices. As we know, various of powerbanks are selling in the market now and becomes important role of smartphone. As end user, what they really care about is the real juice of power bank external battery charger itself. How do we identify its performance good or bad? We woud like share some tips to check the real capacity. 1. The included USB cable, the link between Power Bank and mobile phone. USB cable will be one reason to cause the energy losing:Circuit switching loss;Resistance loss;The voltage loss;Power supply loss;Operation loss of Power Bank. 2. Basic knowledge of power banks capacity: the Power Bank's capaicty is marked according to the batteries inside, but the actual output is less than the nominal capacity. For example: 6000mah power bank with so-called 90% conversion rate, but it turns out it can not provide the power of 3 times to iphone 4S (ps: the capacity of iphone 4s 1460mah) 6000÷1460≈4.11 which means 6000mah is fully charge one iphone 4s 4 times. Why it is far away our expection? The answer is Power Bank conversion efficiency. According to energy conservation rate rule: the capacity of 6000mAh PowerBank is 6000mAH×3.7V=22.2Wh. After transform input voltage from 3.7V to 5V, the total energy is constant, but the capacity has changed into 22Wh÷5V=4400mAH. It likes put 3.7L water into 5L glass. After first conversion, the 6000mAh capacity remain 74%, namely, the 4400mAh is the reality capacity can provide to mobile phone.Energy loss in charging.