Know this before you buy a portable charger:
The labelled mAh (milliamps per hour) is only half the story, you need to know the charge cycle rate.
How do you work out the “real capacity” of the charger? – The package labelled mAh of the battery is NOT the actual mAh of the charger. You can’t simply calculate the “charge cycle rate” of a portable charger by dividing the mAh of the portable charger by the mAh of your phone (Portable charger = 6000 mAh / iPhone = 1400 mAh therefore it will charge your phone 4.2x). It simply does not work like that because there are great losses of energy.
The first variable is the PCB (chipset) which is largely responsible for efficient output of electrical charge into the phone through a cable and the input of electrical charge to fill the charger with more power. The second variable is the phones battery has a health score. The older the battery the more resistant it is to being charged – the older the phone / battery the longer it will take to charge and the more electrical charge required. Once you know the “real capacity” (charger efficiency rate = 80% and the phones health rate = 80% and then deducted from the total charger mAh) you can work out the “charge cycle” of the portable charger.
Don’t be deceived by the price of the charger – Quality high priced components (Battery cells + PCB + Cable) all make the charger work for longer, give higher outputs, holds charge, charges safely and efficiently.
Note: If the packaging does not indicate the “charge cycle” (how many times it will charge your phone) then its more than likely hiding something like an inferior chipset or battery (if they are all there).