I’ve been waiting to get a good Power Bank so I can recharge my iPhone 6 Plus and my iPad when on the go. I didn’t want a too small Power Bank. I use my iPad quite a lot, so one of the main features it needed was the ability to quick charge at 2.1 Ampere. After comparing the different choices I decided to get a TP-Link TL-PB10400mAh Power Bank. It didn’t take long before I had to test it out by measuring the capacity and the efficiency of the boost converter in it.
The Power Bank I got was a TP-Link TL-PB10400 10400mAh Dual-Port Portable USB Battery Charger Power Bank for Smartphones & Tablets. It has two USB ports, one for 1 Amp charge (slow charge and/or phone), and another for 2 Ampere(quick charge or tablet.)
I charged it fully overnight and then did a complete discharge by charging my Retina iPad and an iPhone. Then I did a full overnight recharge but left the TP-Link Power Bank unconnected for two days. I’ve read some reviews that they have a tendency to lose battery charge capacity just by leaving them unused. I’ll get back to why I think some people have that problem.
Equipment Used For Testing the Power Bank
I used my Maynuo M9811 Programmable DC Electronic Load to load the Power Bank with exactly 1 Amp discharge and did four wire metering at the Power Bank so the power loss in the cables was eliminated using both the Maynuo unit and my Siglent Technologies SDM3055 5.5 Digit Digital Multimeter. I also had a YZXstudio USB Power Meter connected as well, and the test result matched very well.
It’s More Fun To Compute
To make it easier to do other tests on Buck/Boost converters later on I wrote a script in Python to control the electronic DC load, DMM and log all data into a CSV-file from both my computer. I’m thinking of cleaning it up and put it on GitHub. Quite handy.
So How Does It Stack Up?
It works very well! The TP-Link TL-PB10400mAh gave out 6700 mAh, which may sound low. But the 10400mAh specified in the product name and specifications is the actual capacity of the Li-Po batteries inside the unit. And these Li-Po batteries are 3.7 Volt. So to get 5 Volts, you need to use a Boost converter inside the Power Bank to get the power up to 5 Volts. After doing the calculation, the number of milliamp-hours at 3.7 Volts was 9054, giving the Boost Converter an 89% efficiency. In that number, we need to add the two days of inactivity, so I would guess that the boost converter is somewhere around 90-92% efficient. This is quite good.
Disconnect the Charge Cables!
The Power Bank would repeatedly start up at 5.28 Volts for a second or two, drop down to 1.5 Volts and then back again after a couple of seconds if a charging cable was left connected to the Power Bank. This could explain some of the complaints from users that have problems with the Power Bank going flat even when it’s not charging anything. So disconnect the charge cables when not in use and everything should be fine. I’ll try it with a charge cable attached and give it a couple of days to see if that’s the problem.
Otherwise, I’m very pleased with my purchase. The power bank is cheap, small (for its capacity) with a built-in LED-light which could be useful sometimes. The battery capacity indicator is just four LEDs that shows battery capacity left, and for once it’s accurate. Even when the last LED is lit, you still have a lot of capacity left in the battery. All and all, a nicely built unit.
To check the battery charge, just press the only button on the unit. If you hold the button down for a couple of seconds, the LED light turns on. To turn it off again, just hold the button down for a couple of seconds and it turns off.
So, do I like it?
I would recommend this Power Bank without hesitation.