Posts Tagged ‘power bank capacity

Here comes a big power bank with 20 Ah capacity in the form of the ADATA P20000D Power Bank, their largest capacity model which caught our attention precisely with its big capacity, though we are going to be testing other ADATA power banks as well with smaller capacity soon. The ADATA P20000D is pretty big and weights almost half kilogram, but this is the result of the high capacity battery cells inside. The power bank is available in multiple colors and the one we have tested was the black version, though apart from the color difference they are using the same plastic case (being advertised as extremely fire, shock, and impact resistant). It is matte color mostly, though around the edges there is a glossy part that looks nice when the power bank is new, but easily and quickly scratches, so we are not that big fans of that design. Another thing that we do not like that much is the presence of a small LED light being advertised as a flashlight… that power banks simply does not need it as it is a sort of useless, but hey, another key sell point for 2 extra cents. What we find very useful and like is the display that shows the remaining capacity in percentage, it has a backlight as well and also displays the active input and outputs.

20000 mAh ADATA P20000D Power Bank Specifications:
– Capacity: 20000mAh (Rechargeable Lithium-ion battery 72Wh)
– Colors: Black / White / Yellow / Gray / Blue / Dark Blue
– Dimensions (L x W x H): 163 x 80.6 x 23.3 mm / 6.4 x 3.1 x 0.9 in
– Weight: 450g / 15.8oz
– Input: DC 5V/2A (Micro USB)
– Output: DC 5V/2.1A max. (Type-A USB)
– Accessory: Micro USB Cable; User Manual
– Warranty: 1 year


The 20000 mAh ADATA P20000D Power Bank comes with high capacity and that high capacity needs faster charging, though here we have a 5V/2A input that can easily take over 10 hours for a full charge of the batteries inside the device. There are dual USB outputs available, meaning you can charge two devices at the same time, though the combined output is 5V/2.1A, so not dual device fast charging, but two at 1 Amp each or one with thee higher charge current. Looking at the test results we are seeing good and stable voltage discharge curves – 4.94V at 1.0A and 4.8V at 2.1A, though we kind of expected a bit more in terms of actual usable capacity from this 20 Ah power bank… the results we’ve got are pretty much the average you could expect from a decent power bank. The high capacity is nice to have, but the bulky size and big weight certainly do not make that particular power bank from ADATA the best choice to always carry around with you in your bag or backpack.

The performance of the 20000 mAh ADATA P20000D Power Bank in our tests:

– 13544 mAh at 1.0A load
– 12560 mAh at 2.1A load

– 66.94 Wh at 1.0A load
– 60.15 Wh at 2.1A load

The 4000 mAh ASUS ZenPower Slim Power Bank (ABTU015) is a very slim, compact and stylish device for charging your smartphone or other mobile devices on the go from Asus. The 4000 mAh battery is inside a plastic case with a larger matte and smaller glossy surface and that looks pretty nice, however the glossy plastic scratches very easy when touched and very soon it does not look that good anymore. The device also has a single white LED disode that provides “flashlight” functionality that in our opinion is totally useless and the power bank could’ve been better without it anyway. There is an on/off button (used for the flashlight as well) and a small three-LED indicator about the current power bank charge that looks nice and is quite useful. The compact size and weight make the ASUS ZenPower Slim Power Bank perfect to sit in your pocket and save you whenever you need some extra power and cannot use a power charger for your smartphone or other mobile USB gadget and without the glossy plastic part and the LED light it could’ve been a really great small capacity power bank. Do note that ASUS also offers a version of this portable power bank with a smaller 3000 mAh capacity that is apparently with the same specifications as the 4000 mAh version we are testing here, apart from the 1000 mAh lower capacity battery inside it of course.

4000 mAh ASUS ZenPower Slim Power Bank Specifications:
– Battery Type: Rechargeable Li-Polymer Cell
– Battery Capacity: 3.85V/4000 mAh
– Input Power: 5V/1A
– Output Power: 5.1A/1A
– Rating Capacity: 5.1V/2200mAh
– Charging Time: <6 hours with DV 5V/1A standard cable - Dimensions: 115 x 71 x 8.3 mm - Weight: 92 g


We need to see how well the ASUS ZenPower Slim Power Bank manages to perform under our test conditions with a constant current load of 1.0A as per its official rating in order to get a better idea on what to expect in terms of actual usable capacity. In the official specifications Asus rates the useful capacity at 2200 mAh. This was something that we were actually a bit surprised to see mentioned in the official specifications for a power bank as usually manufacturers do not cite these cumbers in their product’s specs. The 2200 mAh rating sounds a bit disappointing for a 4000 mAh battery inside the power bank, but our tests have shown that you will actually be getting more… We managed to get 2574 mAh or 12.11 Wh as usable capacity and that is actually what we consider a very good performance, though the output voltage was a bit lower at about 4.7V, but keeping stable at that value. So good job for Asus for this power bank, but it could’ve been even better without the extra glossiness that easily scratches and the useless LED light “flashlight”.

The performance of the 4000 mAh ASUS ZenPower Slim Power Bank in our tests:

– 2574 mAh at 1.0A load

– 12.11 Wh at 1.0A load

The company GP Batteries is a pretty old and popular name when talking about batteries, but they also started making power banks with the advent of this new product category and they already have a umber of products available. Here we are testing one of their smaller capacity models – the 5000 mAh GP Portable Power Bank (FP05M) that looks and feels nice in terms of design and functionality and specs wise seems promising. It has an aluminum body, a convenient LED indicator for remaining capacity and support for 2.0A charging input and 2.1A charging output.

5000 mAh GP Portable Power Bank (FP05M) Specifications:
– Battery Type: Li-Polymer battery 3.7V 5000mAh
– Input current: 2A
– Output current: 2.1A
– Number of outputs: 1
– Size: 120 x 66 x 13 mm
– Weight: 165 grams (approx.)
– Operation Temperature: 5C ~ 40C
– Recharging time: 5 hours (approx.)


With the 5000 mAh GP Portable Power Bank (FP05M) we have performed our usual 1.0A and 2.1A constant current load tests and you can see the results on the discharge graph above. It is interesting to note the interesting jagged pattern of the discharge cure for both currents we have tested with the electronics of the power bank apparently trying to keep the output voltage closer to the 5V, so the output Wattage would not drop more even though the mAh capacity might still seem higher as we have seen on some other products. We are seeing good results under 1.0A and especially good under 2.1A load for a 5000 mAh power bank, so good job for GP Batteries for this device.

The performance of the 5000 mAh GP Portable Power Bank in our tests:

– 3023 mAh at 1.0A load
– 2896 mAh at 2.1A load

– 15.05 Wh at 1.0A load
– 14.02 Wh at 2.1A load


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