24 January 2015

7 Things You Need To Know Before Buying Power Banks

With the advent of advanced technology, it seems that our gadgets are more dramatically smart yet it  provide lack of battery capacities.

When an important tasks should be done at appropriate time, but sadly you forgot to charge — well, it is very frustrating experience.Then, it is a HEAVEN feeling where you can have a portable power bank to charge your batteries. 

Smartphones are becoming more economical and convenient to carry in our pockets. But with the increase of usage, it needs to be full-charged when an important event takes place.
Power Bank
Power Bank. Image Courtesy: pcadvisor.co.uk
Power Bank is a portable charger used to serve as an "extra battery" or "external charger" for your electronic devices like Laptop, Phones, and Cameras — completely useful for travelers.

While it is also good to buy and carry spare batteries of every device, yet it is not a practical option.

Thus, Power Bank is all you need when you want to charge your devices.

Power banks are now becoming a secondary market commodity next to smartphones and tablets. 

But before buying Power Bank, these are the few Things you need to know About Power Bank

1. Mostly Made in China. As you can see, the majority of the power banks in the market today are actually made in china, you may find it in some online pages with cheaper price range. You already know the notion when reading "made in china", but I don't disclosed it to be bias by one part only and not as a whole, yet, due to some users who give bad comments about the products in China — you are the sole decision-maker in buying products from China.

powerbank made in china
Image: Alibaba
2. Re-Charge Cycles and Its Lifespan. Power bank is better when it has 500 recharge cycles, substandard only has 300 cycles.

In one day, recharging your power bank (500 recharge cycle) will have 500 days lifespan too. It is said that once it is FULLY-CONSUMED, the power bank will no longer be able to RECHARGE to its USUAL capacity and it degrades about 50-70%.

3. Charging. You can charge your power bank via the charger in your electronic devices. Some power banks already contained built-in USB charging capabilities. Older models don't have this feature.

4. mAh. mAh means milli Ampere-hour, it is usually the capacity used to measure electric charge for batteries and power bank.

q mah formula

milliamp-hour = watt-hour × 1000 / V


mAh = Wh × 1000 / V

The typical voltage for Li-Ion in powerbanks is 3.7V, but output can go up to 5V. This is the reason why we see either of the two numbers in smartphones, laptops, or powerbanks.

You may see it in the power bank capacities:
  • 2600mAh
  • 4400mAh
  • 6600mAh
  • 8800mAh
  • 11000mAh
  • 13200mAh
  • 14400mAh

5. AA-Like Rechargeable Batteries . These include 18650 and Li-Polymer. Most power banks use a 65mm AA-like rechargeable batteries connected in a series.

What are the difference between 18650 and Li-Polymer?
  • 18650 size and dimension are fix. Li-Polymer size and dimension are flexible.
  • 18650 produce more heat. Li-Polymer are much more safer
  • 18650 are cheaper. Li-Polymer are more expensive
  • 18650 have higher self discharge rate.Li-Polymer have a very low self discharge rate
  • 18650 battery durability will drop faster. Li-Polymer battery capacity are more durable
  • Common mAh use in 18650 is around 1300mAh to 2200mAh.

6. Does 12000 mAh capacity power bank able to charge 8 times with a 1500 mAh capacity phone or other electronic devices?

This is quite good question in terms of calculation. When a power bank gives 12000 mAh capacity, when calculated to charge a 1500 mAh phone then it will be 8 times right?
  • 12000 mAh / 1500 mAh = 8 charges
Accordingly, this is a common mistake. But for the calculation of total charge time, use this formula:
  • REAL CAPACITY of Power Bank * conversion rate * phone battery health / phone capacity = total charge times

EXAMPLE: 12000 x 0.8 x 0.8 / 1500 = 5.12 charge times
    • Conversation rate is the remaining percentage of the battery after the battery lost in heat or PCB operation.
    • Phone Battery Health how healthy’ your phone battery is.
7. Batteries Will Have the Chance to Explode. Whether is is branded or generic power bank, it will explode. But it is in our mind that expensive branded products are made in fine quality and mostly safe to use (quality assurance). Branded ones have the basic features of short-circuit and over-charging protection as compared with cheaper generic ones.

References: [1] [2] [3] [4]


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