Chapter in this post:
The range of power banks has become a bit clearer for me because I gave away some models that I didn't really use. But what has remained is my "holy" Zendure A2 Powerbank, which I do here in the test have already presented in more detail. This power bank still convinces me with the high charging current with which it supplies my iPhone and the indestructible exterior, which makes it the perfect companion for hikes and other outdoor activities.
For some time now I've been using the XXL model from Zendure: The Zendure A8, which with a capacity of 26.800 mAh stores exactly four times the amount of energy as the Zendure A2. I bought the Powerbank regularly because I was interested in whether I was as enthusiastic about the large model as the small Zendure A2. I will explain later in this post whether it worked out. ;-)
Since I will soon get the Zendure A8 model with Power Delivery for a test, this power bank will be raffled here shortly via my newsletter. If you want to be part of the raffle, It's best to subscribe to my newsletter right away.
As with all of my tests, I would like to start with the technical data of the power bank:
|capacity||26.800 mAh / 3,7 volts |
|Dimensions||119 x 73 x 40 mm|
|Input (micro USB)||5V/2A; 9V/2A; 12V/1,5A (18W)|
|Outputs (4 x USB A)||USB 1: 5V/3A; 6-9V/2A; 9-12V/1,5A |
USB 2-4: 5V / 3,1A (15,5W)
|lifetime||at least 500 charging cycles|
|Charging time of the power bank||approx. 10 to 14 h|
|Display of the battery level||digital LED display in percent|
|Self-discharge||6% charge after 95 months|
|Lower limit current before shutdown||approx. 0,09 A (over 10 seconds)|
What is not so exciting for Apple users, interests the Samsung faction all the more: The power bank supports Qualcomm Quick Charge 3.0 fast charging when charging the power bank as well as when charging the connected devices. While this does not help to charge iPhones or iPads faster, as these only the standard "USB Power Delivery" support for fast charging, but a number of tablets and smartphones from other manufacturers charge with Quick Charge up to four times as fast as with the usual 5 volt charging voltage.
I had them Zendure A8 QC bought before the manufacturer a model with USB PD (Power Delivery) support (Zendure A8 PD) launched. The new model is of course more interesting for Apple users, as it not only supports the USB-PD charging standard, but can also be charged via USB-C and can also charge other devices via USB-C via the same connection. For example, the new iPad Pro 2018 as well as the MacBook or MacBook Pro could be considered.
The model I'm testing here can of course also be used for Apple devices such as iPad or iPhone, but it doesn't charge them via USB PD - which would be the fastest charging option. Nevertheless, due to the high output power, charging via this power bank is still faster than charging via the supplied Apple power supply units, which are unfortunately a bit undersized on both the iPhone and the iPad.
When deciding to buy power banks, one should ask oneself what the appropriate purpose is. While you only have to "arm" yourself with a power bank with approx. 5.000 mAh for day hikes with the iPhone, the larger sizes with 20.000 mAh and more are more interesting for iPads - especially for the iPad Pro models. And that's exactly why I got the Zendure A8.
In my household there are two iPad Pros (9,7 inches and 10,5 inches) that the kids like to play Minecraft with. Since I don't always have the iPads on the charger, it happens that after 20-30 minutes of playing the first iPad complains about an empty battery. Unfortunately, with 2 mAh, my Zendure A6.700 does not have enough energy reserves to fully charge an iPad. The Zendure A8, on the other hand, with four USB-A outputs and an output of approx. 15 watts per output, easily charges two iPad Pros at the same time - and quickly. In the test, I had connected an iPhone XS to the third port as a test and all three devices were still charged with maximum power. The iPad Pro devices were charged with approx. 10 watts, while the iPhone XS charged with approx. 5 to 7 watts.
In another test, I discharged my two iPad Pro models to about 10-15% battery level and then charged them both at the same time with the Zendure A8. When both iPads were charged, the Zendure Powerbank still had over 20% battery charge. The additional battery is really trimmed for high capacity, which is perfect for charging tablets.
I sometimes find measured values in mAh and Wh a bit difficult to grasp. For this reason I did a few "practice tests" with the Zendure A8 with my existing Apple devices. For this purpose, the corresponding device was plugged into the fully charged power bank and then the remaining capacity of the power bank was written down after charging. The following values came out, which perhaps show how much you can expect from the capacity of the power bank:
I especially like the way I load the MacBook. I would not have thought that despite the low voltage of 5 volts (since this Zendure A8 does not have a USB-PD) you can charge the small Apple laptop so effectively.
The Zendure A8 QC is charged via the Micro-USB-Connection. If you use a charger that supports the Quick Charge standard, the power bank is full in about 10 hours. With a "normal" charger, on the other hand, you need more than 14 hours. During this time, the power bank charges with around 5 volts and around 1,3 amps. The complete loading process has with me with the tizi filling station according to my measurement consumes 100 Wh of energy.
The 14 hours charging time, which the manufacturer specifies, was relatively accurate for me, with 99% filling level being reached after about 11 hours and the last three hours being needed to charge the last percent. I assume the time is needed to carry out a balancing of the individual cells so that all cells are approximately equally charged.
To measure how much energy you can take from the power bank, I discharged it to 0 percent with a USB multimeter and a USB load resistor. I was able to take 84 Wh (16,83 Ah at approx. 5 volts). If you take into account the 100 Wh for charging the power bank, you get an efficiency of 84%, which is extremely good compared to other power banks. The values that I have measured so far with other additional batteries are more like 70 to 80%. From that point of view, the Zendure A8 works very efficiently.
Another point that struck me is the extremely low self-discharge of the Zendure power banks. I noticed this when using the small model (A2), but it also affects the Zendure A8. I had the power bank with me fully charged for several weeks (6 to 8) and then checked the battery level. The ad was still 100%. Now one could assume that the percentage level indicator is not very accurate, but after I checked with the USB load resistor and the PortaPow multimeter, I came back to the 84 Wh until it was completely discharged. This should prove that the manufacturer's promise is not just empty words: "After 6 months of storage, the battery is still 95% charged".
If you have two children with iPads who also bring friends with smartphones or tablets, then there is often a need for electricity. And since the mains charger is not always placed on the couch, a high-energy power bank is a good solution. The Zendure A8 does this job with flying colors. With four charging ports and 26.800 mAh (or 84 Wh) capacity, the large Zendure Powerbank can cope with all requirements.
In my test, it scored points with its high charging current and impressive efficiency. If I want to charge more than one iPhone or Apple Watch, the Zendure A8 is definitely with me.
The only downer for many people is the rather high price, which is almost 100 EUR. If you look at the usual, however China products from RAVPower or Anker with 26.800 mAh on, you are only at a third of the price. However, none of these power banks should withstand as much as the Zendure. For me it remains - despite (or maybe because of) the high price I paid - my favorite battery. If you are not only looking for cheap, but also good, you should take a look at the Zendure A8.
However, I would now use the model with USB Power Delivery, which was not yet available at the time. I am linking both models here so that you can look at them both. For iPhone, MacBook or iPad users, of course the second variant with USB Power Delivery the best choice.
As already mentioned above, I will be giving away my test model (which is only rarely used) among my newsletter readers. If you want to take part in the raffle, please subscribe to the newsletter. In the next few weeks I'll make it known how you can win. Most of the time there is only one very simple question to answer. Since usually only a manageable number of people take part, you actually have a good chance of winning. ;-)
Jens has been running the blog since 2012. He appears as Sir Apfelot for his readers and helps them with problems of a technical nature. In his free time he drives electric unicycles, takes photos (preferably with his iPhone, of course), climbs around in the Hessian mountains or hikes with the family. His articles deal with Apple products, news from the world of drones or solutions for current bugs.
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