A1 Double USB Power Bank 15000mAh External Battery for iPhone 6 Samsung S7 Portable Universal Quick Charger 3.0 Power Bank Output 2A
All power bank during the charging process, power is not fully converted, there will be some loss.
1, the circuit switching losses. I believe we all know, mobile power charging time may have fever, according to the law of conservation of energy, heat energy is actually built-in battery.
2, resistive losses. When to charge the phone, built-in battery and power between the mobile phone battery through the circuit board and wiring. We know that there are those who conductor resistance, 0 no resistance conductor (superconducting outside this range). The main physical characteristic resistance is the electrical energy into heat, so during the charging process, there will be the conductor generates heat, will have fever and loss of energy dissipation.
3, the voltage loss. Lithium battery discharge voltage is not static, safe discharge voltage range of 4.2V-2.7V, the power converter will be different. General discharge voltage range of 3.6-3.9V, will be able to release the battery to 80% or even higher power, and if outside this range, the power consumption will increase.
4, power loss. When charging the phone, only to charge the battery, but also for other parts of the power supply, especially in the screen of the mobile power supply is a power-hungry.
5, self-loss. During charging, mobile power also need to maintain their own power to run powered by internal batteries, these same power.
These losses by achieving a cell phone’s battery is about 85% of the actual battery cells, battery capacity of the actual output power in the meantime lost about 38 percent of its electricity. That is, the “actual capacity continued conversion” only about 62%.
In summary, mobile power normal conversion was 60% -80%.
Sometimes due to long shipping, the battery might have lost its power. Need to charge for some time then it will work. Thank u.