There’s no denying that power bank is an awesome invention, it has become one of the most necessary smartphone accessories these days.
Before you buy a power bank you might put an eye on how many times the power bank can fully charge your device, for example, if it is a 10000 mAh rated power bank, you might expect to charge your 2000 mAh phone for five times, actually it is a completely wrong calculation method.
First of all, you need to consider the power conversion rate which is regarded as efficiency. When power is transferred from a power bank , there is always loss due to resistance. Let’s take the industry standard conversion rate of 80% – 90% into account, the methodology becomes: Power Bank capacity * Conversion Rate / Phone battery capacity. Is it finished? Not yet.
Another factor you have to consider is the battery health condition of your device. The battery is strongest when it is new, with age and with charge cycles, the health of the battery keeps going down. There are Apps to measure the health rating number of your phone battery, generally speaking, if your phone or devices have already been used over a year, you might need to multiply health rate number around 80%.
Now, let’s put everything mentioned together.
How many times can a 10000 mAh rated power bank fully charge a 1-year-old iPhone 6 ?
Apply the formula: Power Bank capacity * Conversion Rate * Phone Battery health rate / Phone battery capacity = 10000 mAh * 80% * 80% / 1810 mAh =3.75 times
The methodology above is just an approximate evaluation of the charging times, if you want to dig out more, you need to get the knowledge of internal configuration of the power bank, like the type of battery and PCB ( printed circuit broad ).
Most power banks come with Li-ion or Li-Polymer battery cells, the cheap ones are mainly made with Li-ion 18650 batteries, literally the capacity of a 18650 cell is no more than 4000 mAh, therefore you can simply detect if the manufacturer lied about the capacity by observing the size of power bank. However, the shortage of 18650 battery is lower durability and higher heat release to be compared with Li-Polymer battery, the heating problem would affect the charging efficiency and result in reduction of charging cycles. It’s much safer to use Li-Polymer cell due to the explosion risk of 18650 Li-ion cells.
The quality of PCB is rather important as it will decide how much charge the power bank can provide at full capacity.
Some users would like to add voltage into calculation since most power banks are with rated voltage 3.7V and the standard input voltage of smart devices is 5V, is it necessary to take the voltage into account? Not so much, in fact the internal voltage of the smartphone battery is also 3.7V, of course there is a few power loss due to the voltage step-down.
Recommendations for 10000 mAh rated power banks:
Check Out with Code: 10KBMC1
- Quick Charge: Up to 18W output, offer the fastest charge for your phones and devices, QC quick charge support
- Super Portable: With a compact size as an iPhone 5S, fit your phones slimly, enables super easy one-handed holding and pocket-friendly carrying.
- Built-in Flashlight: Prepared for unexpected power failure, dark night walking, and more.
- What You Get: EasyAcc Slim 10000mAh Power Bank, Micro USB Cable, User Manual, 18-month worry-free warranty and friendly customer service.
- Fast Charge: Smart technology intelligently detects your devices and deliver the fastest charge. Charge two smartphones or an iPad at full speed (Smart Output : 5V 3.1A). Recharges in 6 hours with a 2A adapter (not included)
- Compact & Portable Design: Compact with Apple, Samsung, HTC Smartphones and Tablets, and other devices with USB Charging port. Easy to hold in your hand and put anywhere you want, e.g. a pocket or bag.
- Safety Protection: Effectively prevents your devices from overcharge, overcurrent and short circuits as well as conform to CE, RoHS, and FCC specifications.
- Remarkably Compact: One of the smallest and lightest 10000mAh portable charger. Provides almost three-and-a-half iPhone 6s charges or two-and-a-half Galaxy S6 charges.
- High-speed-Charging Technology: Anker’s exclusive PowerIQ and VoltageBoost combine to deliver the fastest possible charge for any device. Qualcomm Quick Charge not supported.
- Certified Safe: Anker’s MultiProtect safety system ensures complete protection for you and your devices.