You should read the first few posts. Probably you have sandbags or corroded batteries in the power bank.

How much did you pay for it.

Buy from reputable joints. As to brands, there are way too many, but good ones at 100 should be from 5000 to 7800 mAh.

The phone/tablet will pull the required current. If the pb cannot supply enough it will just charge slower. This is fine in most cases except for some tablets that require a specific resistance value in the cable.

You can, right? From the first pic you seem to have the replacement batteries (red) already.

Some soldering will do?

Have you tried different cables and the Galaxy Charging Current app?

This gives you a quantitative comparison.

The GCC Now and Avg readings will show you what the powerbank is giving your phone. For the 2.1A port, it should give you a max reading of 1800 for a few seconds from screen off, then drop to 1200. This applies for S4 and Note 3.

You MIGHT have some bad cables, or bad powerbanks. My cables are verified for 1800 from the AC charger first then I will test the powerbank.

If your cables are not giving you 1800 even from AC then you have lousy cables.

Is that a LiPo from RC planes? What converter did you use?

AllinGap is correct. For simple verification, just measure the length of the powerbank. 18650 means 18mm diameter x 650mm length.

6 cells will give you 6 x18mm minimum length, plus another 20mm or 25mm for the circuit board. If it is any longer it means that there are more cells.

Still, to reach 30000mah will need at least 8 cells with current 18650 technology. Unless they use lithium polymer packs.

Did you open it up to see what's inside?

The S4 and Note 3 will only show 1200 if it is left on for more than 3 seconds after screen on. Within approx 3 seconds of screen on it will show 1800.

Note 2 should show 1800 if the port outputs 2.1A.

For Samsungs, the app Galaxy Charging Current works.

For most other devices, you can read the values from some file in /etc I think. Can't recall. It's the value reported by the OS.

Otherwise the charge/discharge graph from BatteryMonitorWidget is accurate enough for practical purposes.

Of course, because your screen is already on for more than 3 seconds.

I suggest you let the screen blank out, wait about 5 seconds, then turn on the screen and immediately run GCC. It should show you 1800 for a few seconds, then drop to 1200. This is how S4 and Note 3 behave.

Note 2 should consistently show 1800.

Again, if the pb output doesn't provide 2.1A, then that's a different story. Try various cables and see if the readout differs.

Hi all I want to share my teardown / disassembly of the Mi 10400mah Powerbank.

1. Slowly prise off the white plastic fascia on both ends. A small, sharp knife will do best with the least amount of chipping to the aluminium and plastic itself. Just be careful of the retention clips, but they are not clipped. Some small force will release them.

After the fascia is removed, unscrew 4 screws on each end.

Front fascia removed




Rear fascia removed



2. After the screws are removed, use something to prise out the rear stopper or plug. You may use the stickiness of the double-sided tape that remains on the plug to help in lifting it up using your fingers as a surface.

Rear stopper removed




3. After the rear stopper is removed, you may gently push the entire assembly from the rear towards the front.






4. Closeup of the board.





UPDATE: added closeups of the board. There is an oddly named chip on the lower right below the VDD text.

Very nice board, and even has a thermocouple for heat control. VERY NICE touch.

To re-assemble, reverse the steps.

Hope this helps TS for investigation.

This post has been edited by joytest: Jul 13 2014, 12:18 AM

The cells read LGDBB41865.

Googling gives only LGABB41865.

I don't know if the 3rd letter indicates the cell quality.

I can't say much about cell quality but the board is top notch multilayer machine laid soldered components. Should be at least 2 layers. TS may have some more informed comments since he is in the industry.

One of the other powerbanks I've opened has got very sparse component layout and simple circuitry.

I am updating the post with shots of the chips on both sides.

An interesting read about powerbanks and swapping the cells to better quality ones.

http://goughlui.com/?p=4321

That is what I am thinking of doing.

Psychology?

China = no good.
White dudes = good.

Even if it output 10A, your device will only pull its max rating. So if your device says 1.5A input, you'll only ever be pulling 1.5A.

Yes plenty. They look almost identical and you can't tell from the external appearance.

One of the methods to test is to connect the usb cable to charge itself ie loop the cable to short the powerbank.

Fake ones will have the LEDs light up while the genuine one will not light up. light

Hi all,

This blogger did a teardown and full load testing with his equipment for the Mi 10400 powerbank. I recommended him to test and he actually went ahead with it.

http://goughlui.com/2014/10/02/review-tear...mah-power-bank/

I have been reading his blog a bit and he has torn down a lot of powerbanks. His conclusion on the Mi pb is that he is simply amazed at the performance of such an inexpensive piece of kit.

It is 85% efficient at 2A output !!!