Power Bank FAQ

Lithium Ion, also known as 18650 Lithium Battery cell, is an older generation battery which is still the most commonly used batteries in lower capacity power banks. This is mainly due to their low price. This is the most common Lithium battery type.

Lithium Polymer, is a more advanced battery with higher specs and provides higher level of safety features, they are therefore more expensive than Lithium Ion batteries.   Despite the higher price, It is advisable to go for Lithium Polymer Power Banks especially when it comes to higher capacity power banks.

One misconception about power banks is that when it says 10 000mAh you think the usable capacity is 10 000mAh, in fact, the usable capacity is closer to 60% – 70% of the battery capacity.  This is due to inefficiencies and heat loss.  On top of that many power banks have lower battery capacities than what they say on the label.

Fake capacity power banks are a dime a dozen right now in China.  We have personally tested our supplier’s power banks to ensure their quality and to check their battery testing compliance.

We have specialised testing equipment that allows us to place a load on the power bank or battery we are testing and then measure the output duration of the battery.  This gives us the true capacity of a battery or power bank.   Feel free to pop into our office to see this equipment and test any of our power banks.

MAh is an abbreviation of milliampere hour.   A milliampere hour (mAh) is 1000th of an ampere hour (Ah).  Both measures are commonly used to describe the energy charge that a battery will hold and how long a device will run before the battery needs recharging. A Power banks capacity is measured in mAh to give you an indication of how much power they hold and how many times they can charge your device.

The charging cable used with your power bank can make a big difference in the power banks performance.  It’s of no use have a power bank with 1000mAh output when the cable is only rated to 500mAh.  The cable is limiting the output power by 50%.

This image shows cable testing apparatus used by our factory to test every single cable and adapter before shipping to us.

Power Bank cable testing

We have thoroughly tested our cables can assist with the correct choice.  All our power banks are paired with cables that are of suitable power ratings for that particular power bank.  For more information and great charging cables ideas visit www.chargingcables.co.za

If you are unsure which adapters or cables to use with a power bank, the easiest solution is to use the USB cable that came with your device.   You can study the adapter on that cable to identify which adapter to use by simply comparing them.

Multi adapters

We can supply cables with multi adapters so that our power banks can be used with many brands or types of devices.  The above 3 in 1 cable covers over 98% of new cell phones in South Africa.

When charging a Power Bank it depends on a few factors as to how long it will take to charge.  Firstly the charger used makes a difference in charging time.  Different chargers have different power output strengths.  All chargers with a USB port are 5V output however the output amperes or milliamperes (mA) will vary.   For example:

• Computer port 0.5A or 500mA output
• Most wall chargers 1A output or 1000mA
• iPad wall chargers have a 2.1A or 2100mAh output  and are not suggested for charging cheaper power banks.

A second factor is that the Power Bank itself has input power regulating technology built in.  This is a feature to protect the battery.   Most power banks have a maximum of 1 – 2.1A input power rating.

The third factor is inefficiency in the charge process.  20% power is lost during the charge and discharge process.

PowerBank charge time Example:
Powerbank: 2600 mAh  (0% remaining)
Power Supply/ Input: 1000mA plug
Calculation: 2600mAh/ *800mA = minimum 3.25 hours
(*Why 800mA? An estimate of 20% power is consumed during the charging/ discharging process)

Same calculation using PC port, 0.5mA:
Powerbank: 2600mAh (0% remaining)
PC USB Port : 500mA
Calculation: 2600mAh/ 400mA = minimum 6.5 hours
(Why 400mA? An estimate of 20% power is consumed during the charging/ discharging process)

The time it takes to charge a device with a power bank is dependent on a number of factors.  Firstly and most important is the output of the Power Bank, most are 1A output.  Only larger capacity power banks (5000mAh +) will have a 2A or 2.1A output.    A second important factor is the resistance of the cable used.  Some cables only have a 1A capacity capability.

The same calculation as above can be used to calculate how long the power bank will take to charge a device.  The example below assumes there is 0% power left in device battery.

Powerbank output: 1A
Phone battery: 1500mAh
Calculation: 1500mAh / 800mAh =  1.875 hours
(Why 800mA? An estimate of 20% power is consumed during the charging/ discharging process)

Below is a diagram showing some common mobile phones battery capacity.

Once again this comes down to simple mathematics.
Powerbank: 10000mAh (full at 90%)
Phone Battery: 1500mAh
Calculation: (10000mAh x 90% x 80%) / 1500mAh = up to 5 times
(Why 90%? Assuming the power bank is well maintained in good working condition and can conserve up to 90% power)
(Why 80%? An estimate of 20% power is consumed during the charging/ discharging process)