Power Bank 10000mah 20000mah Portable Charging Led External Battery Pd 20w Quick

We offer two kind programs for you, you can choose according to your needs.
①:PD power bank【Fast Charging QC3.0】 (Orange)
②:Power bank【Ordinary Charging 5V/2.1A(Green)
FAQ
Q: Power bank has two regular standard of capacity , one is the battery capacity, one is the rated capacity.  The 20000mah power bank, being labeled 20000mah/3.7v core capacity be converted to rated capacity 13000mah/5v.
Why exist this happening?
A:The most important reason is the conversion rate. Because most of power bank's battery voltage is 3.7V, and power bank needs to increase the voltage to 5V when charging the mobile phone, which making the power bank's conversion efficiency only 3.75/5=74%, Also include generated heat when battery voltage boosting, and various of wire consumption, Electricity and self-consumption. these points add up to account for 30%-40% of the power of the mobile power source.So the 20,000mAh power bank can really be used by us only about 13000mAh. 
Tips:
This link has three different models, please choose according to your needs, do not buy the wrong product.