Will34's Powerbank Reviews Thread

Hi all, as many of you might know I have been doing some power bank reviews lately, so to keep everything in order I decided to create an All-in-one thread with all of my upcoming and some existing reviews. I just got some new testing devices that will help me take measurements more accurately, and I have come up with a new chart style to show the information as clear as possible.

Since this is just a very part time hobby as I do with flashlights, for now none of my reviews is a product sent by anyone so do expect it 100% unbiased. :wink: I can’t explain it but I have this “weird” interest towards chargers, batteries and cables (or power devices in general), well… partly because they are related to my job, but let’s say there’s some fun when doing all these testings, much like modding flashlights even though I don’t need any more of them.

Hopefully my reviews can be helpful to you, and please feel free to ask anything related. :smiley:

  1. Aukey PB-N37: 5,000mAh, single port 1x26650 compact powerbank.
  1. EasyAcc PB3350: 3,350mAh, single port 1x18650 compact powerbank.

Coming soon: Photive 9,000mAh rugged powerbank, YZXstudio 7th Gen 4-Cell powerbank, Letv 13,400mah, Anker powercore 13,400.


“AUKEY Mini 5000mAh Ultra Portable Charger”

Normally I don’t even look at low capacity single cell powerbanks, but this one is very special: instead of using 18650 as nearly all other in this size does, the Aukey mini uses a 26650.

Details and spec:
-Price and link: $9.99 from http://www.amazon.com/gp/product/B01B1DTASC
-Rated capacity: 5,000mAh, 3.7V
-Rated input/output: 5V 2A / 5V 2A
-Weight & size: 127.5g, 91x30mm
-Ports: 1x USB out, 1x microUSB in


Aesthetic and teardown:

The PB-N37 arrived in a simple recycled cardboard box, nothing fancy here, plastic-free packaging is the way to go!

Inside the box: a short usb cable, instructions manual, warranty card, and the powerbank.

It comes in a variety of colors, but all of them with a white cap. I think it’s a bit generic-looking. The aluminium parts have flawless anodizing and overall build quality is good.

Size comparison with the i6. It feels very compact in hand, and can be even carried comfortably in a jeans pocket.

It can be easily disassembled by removing both caps

The no-brand 26650 inside, I couln’t find any spec about this battery

Circuit board close-up, notice the branding on the board and the very recent production date.


-This powerbank is fully automatic, there is no button on the device.
-By connecting any load it will turn on and will shut down after 15 seconds if the load is <200mA.
–3 color LEDs shows the battery charge level.
-Default coding is Apple 2.4A or DCP 1.5A as shown by my YZXstudio meter.

Following chart shows discharge tests at 0.5A, 1A and 1.5A. I didn’t bother with 2A because it couldn’t handle 1.5A very well:

The boost circuit although being very efficient at lower loads, it seem to struggle at 1.5A: during the first hour the voltage was stable at 5.05V but after 1hr10min, it dropped very quickly to 4.8V and at 1hr30min it was already down to 4.5V. Normally anything putting out below 4.7V is not acceptable and will not charge your device at decent speed. It continued at 4.5V for the rest of the discharge period. Efficiency doesn’t seem to be affected much by the low voltage output.

However, this powerbank will work very well for low-drain devices such as the iPhone except the 6S and Plus models since those will draw above 1.5A. Also for most mid-range android smartphones that don’t draw more than 1-1.2A will charge just fine. I’m safe to say the problem is not the battery, being a 26650 it should handle this current draw with no problem, but the boost circuit is not very well designed and the 5V 2A rating is too optimistic as it is only valid for the first 45 minutes at this discharge rate.

–16Wh of output energy translates roughly into two full charges for the iPhone 6. For the size of it this is actually very decent.
-To recharge it back, it took 3hr 11m and 23.2Wh with a 5V2A adapter.


I will rate this powerbank 6/10, considering it provides high capacity for the size and has good efficiency at lower discharge rates. But if you have a power hungry device, look elsewhere. For $9.99 you might as well consider other powerbanks with double the capacity, some of them just a couple bucks away. The $14.99 Xiaomi 10,000mAh is a very good alternative.

Sorry, it do not work that way. The YZXStudio meter will show DCP every time the two data pins has the same voltage, but they must be floating to be a DCP and this is not checked by the YZXStudio meter. I.e. the output is either DCP (If the pins are floating) or Apple 2.4A if the pins are fixed voltage.

Thanks for the explanation, in my Y1266 meter it shows “Or DCP 1.5A” under the actual coding with most of my powerbanks and in this case the pins had fixed voltage of ~2.7V, so I guess it is actually apple 2.4A but the meter is not able to tell if the pins are floating or not, so it displays DCP?

Correct, any coding with equal voltage on the two data pins will include a DCP as second choice. If the voltage do not match any other coding it will only show DCP.

Nice review! Are you going to test some Anker powerbanks, too?

“EasyAcc PB3350CS Powerbank Review”

Sorry for the delay of this one, I actually had the review for some time but haven’t had the time to upload it. Found this powerbank on Amazon as one of the daily deals, for just $6.99 it seemed like a good deal and I couldn’t pass it. This is going to be a short review because there is really not much to talk about it. :slight_smile:


Details and spec:
-Price and link: $6.99 http://www.amazon.com/dp/B01423C81Y
-Rated capacity: 3,350mAh, 3.7V
-Rated input/output: 5V 2A / 5V 1A
-Weight & size: 71g, 101x 24x 24mm
-Ports: 1x USB out, 1x microUSB in


Aesthetic and build quality:

Same as the previous reviewed powerbank, it came in a simple cardboard box. This package is being used on so many gadgets now, and I prefer this a lot more over the conventional color printed box. It comes with a user manual and a short microUSB cable.

It feels quite well built, the plastic has matte finish and does not immediately scream cheap when held. It uses a single button to turn on and check the battery level, which is displayed in 4 blue LEDs.

In the back we get some details: it’s curious how they decided to show the energy (Wh) in full details by just multiplying voltage x capacity. Even if the circuity was 100% efficient, a 3,350mAh battery will very unlikely yield all of that capacity. Most manufacturers use Min/Typ rating and 3.6V volt, since the battery is not discharged in full.

The size is roughly the same as the S2+.


Operation and Performance:
-This powerbank is operated by a single button, does not have automatic turn on.
-Will shut down after 10 seconds if the load is <150mA.
–4 blue LEDs shows the battery charge level.
-Default coding is Apple 1A as shown by my YZXstudio meter. By connecting a smart device, it will only pull 1A. But because my USB load is just a dumb load, it can ignore the coding and pull more than that.

Following chart shows discharge tests at 0.5A, 1A and 1.5A. Didn’t test 2A because that would be too much load on a single cell:

As you may have expected, the highest efficiency is achieved with the lowest load. I got lower than usual efficiency at 1A so I tested it repeatedly, however I got the same result from all tests. 78.7% efficiency at 1A is not too bad for a single cell, and at 1.5A 67% is a bit alarming. But in real use you won’t see this because the output is limited at 1A when connecting a smartphone.

-They advertise 120% of charge for an iPhone 6, and I can confirm this is true. I got 9.78Wh at 1A which is rougly 1.14 times the energy needed to charge an i6 (~8.5Wh).
-The boost driver in this unit was able to maintain a healthy voltage until exhaustion. This means you will always get the same steady charge rate.
-Note that my efficiency rating is based on what they advertise, I doubt the battery is really 12.39Wh so the real efficiency should higher. (a Sanyo GA is only 12.8Wh at very low discharge rate)
-To recharge it back, it took 3hr 7min and 12.19Wh from a 5V 2A source. About the same time it takes to charge an 18650.


Considering the price and the fact that this is a single cell powerbank, I would say the performance is more than acceptable. Being able to provide a full charge to a modern smartphone on the go while being compact enough to carry without being noticed is a big plus. If you can get this for the same price I did ($6.99) then I would definitely get one, but at the current price of $9.99… no so much. I rate this 7/10.

Thanks for the thread will34. I also have a collection of assorted power banks from various sources.

One question that pops up from time to time is whether these banks can work as “buffers” on small solar panels when camping. Some chargers are unreliable when connected direct to an intermittent solar source. (Think days with passing cloud.) The Sanyo USB eneloop charger is one example.
Then of course there is the well documented “iToys” problem of charging not automatically resuming after being interrupted.

I like to put a power bank between the solar panel and the device being charged in this case.

In testing of my own devices:

1. Some will not output at all when charging. (Onix model from Aldi)
2. Some will keep a correct and steady USB output regardless of incoming charge. (A no-name 4x18650 from Cottonpickers, a couple of Miller ML-102s and two Goal Zero products.)
3. Some output a voltage that reflects the incoming voltage making them useless in low-light conditions. (This includes the otherwise excellent Xiaomi banks.)

Would it be possible for you to comment on how your reviewed banks perform in this respect? I don’t have any sophisticated bench supplies so I usually just monitor the incoming and outgoing current/voltage using two charger doctor devices. But I need to wait for a partly cloudy day to do my testing….


Great reviews but I noticed you mentioned pocket carry on these and I’ve had a bad experience with doing just that. Pocket lint and trash will get into the USB ports. I actually thought I had one go bad because it wouldn’t charge until I tore it apart and then figured out what the problem was. A easy and simple fix is rubber chair leg caps of the right size to cover it. Easy to source but big and bulky. If you know an electrician sometimes big rolls of cable come with a thinner rubber cap over the end of the cable. I wish I could find more of them myself even being a sparky. Guess one could but port plugs but a single end cap is easier to keep up with but I’m the type that could loose my head if it wasn’t attached.

Hey, what about the YZXStudio 7th generation powerbank review?
Would be nice to know your opinion :slight_smile:

Thanks to this thread I learned about the Aukey PB-N37, 5000mAh, single cell 26650 powerbank. I like the fact that both endcaps can be screwed off. This way you can test the cell or even replace it if necessary. On the other hand I would not recommend it to those unfamiliar with li-ion safety, so it is more of an enthusiast’s powerbank.

I bought one online for €9,99 and it’s in fact very easily taken apart and desoldered:




Cylinder and endcaps are aluminium and both caps screw off.

The whole package sits tight enough in the cylinder so it does not rattle, but it simply slides out to the electronics side (it’s a bit tighter when pulling out on the cell side).

The cell looks like a PLB INR26650-50A (the cell Liitokala uses for their 26650-50A) and my test showed a capacity of 5048mAh at 1.5A discharge rate on a Miboxer C2-4000. That’s a very good result.

The electronic has a very small current drain when the powerbank is unused. I soldered a 0.1Ohm shunt between cell and board and with a UNI-T UT61E measured a voltage drop of 0.00-0.01mV. This translates to <0.1mA.

The powerbank activates when an USB connector is inserted and deactivates when no current is drawn or when unplugged. There is no switch. It has an LED on the PCB to indicate charging (green) or roughly the charge state (red, green, blue).

The powerbank charges the cell to 4.19V resting, it discharges down to 2.89V and then turnes itself off.

I charged several phones and electronic toys with the powerbank, as well as using it to power a Lii-202 charger with a 2A current draw.


Electronics and cell:

Thanks for the review HQ. Its good to see a quality cell used. :+1:

A nice solution to this is a silicon diffuser, which then serves a double purpose.

My Aukey PB-T12 was bought a couple of years ago and it had “Wintonic” cell. It’s a real nice and efficient QC3.0 power bank measured at 17.5Wh at 1A discharge.

Hi everyone!

My PB-N37 stopped charging a few days ago, whatever I tried (changing chargers and cables, leaving it on the charge overnight) - it just lights on the green LED, but if I try to connect any device - it tries to charge it and goes off right away.

As far as I see, the resistor (I guess) marked R22 on the PCB went kinda black and gets VERY hot while powerbank connected to the charger.
So… My questions are:

  1. Might the burned resistor cause this problem?
  2. Is it possible to replace the damaged resistor? And if so, what characteristics it must have? I see “100” on the photos above, but I’m really not sure this is sufficient information.
  3. Is it worthy to mess with the repair at all? I mean…

Would be really grateful for any help.

Yeah, I was very happy when I saw the PLB cell, as Powerlongbattery, although being not a major manufacturer, seems to be top notch when it comes to 26650 cells, producing consistent quality and living up to their mAh claims.