ASDA "blackweb" 10000mah Powerbank

I have been playing with some ASDA blackweb 10000mah Power Banks that ASDA has been discounting recently to first £12 and now £8.

At that price they are a reasonable source for Li-ion cells without any other circuitry, but I did wonder why they were discounted so far!  I think I now have a possible reason they may be trying to clear them out.

I have been playing with some ZXETECH devices, these are designed to test batteries and power supply products.

I have a EBD-USB+ which is a compact device with USB in USB out and usb control, this usb control gives an easy access to the device readings and is used with a small PC control program "EB Tester Software" to pun this meter / load device.

Since I purchased this I have also purchased the EBC-A05+ which also gives battery charging, load testing, PC cyclic testing control and hence can automate a battery test by first charging a cell then discharging the cell under controlled constant current or constant power loads, followed by recharging the cell. This is all under PC contol using the same program as provided for the EBD-USB+ which has many more options whilst controlling the EBC-A05+.

So I have been testing a number of batteries, power banks, power supplies using these devices.

I am still shuddering by the number of Li-on cells in my stores which are fakes and have only about 10% of their rated capacity! (NB a good 18650 weighs about 45gms whilst the fakes weigh only about 36gm making the cell weight a good estimator of battery quality.)

During this period of playing I purchased for £12 an ASDA blackweb 10000mah and decided to see if it was a fair rating for the device. Allowing for the fact that the 10000mah is the cells capacity at about 3.7v and the device provides an up-converted 5v and allowing for approx 90% efficiency the banks performance was well within expected specification, although  it is a pity that the usable capacity at 5v is not used for rating the banks!

Having completed that test I decided to look at the two output one specified as 1A the other is 2.1A. Testing the 1A output proved uneventful with the required specification easily met and the overload shutdown working as expected.

Testing the 2.1A output was a bit of a surprise as instead of an overload protection cutting in the load functioned for a short time at over 3A. It then shut down and this output became dead.

On investigation the 2.1 A USB socket had un-soldered itself from the circuit board before the overload protection had cut in. Under magnification I could see that 3 of the 4 pins on the socket had melted their solder and raised off the PCB!

On re-soldering the connector the battery pack now works fine. However possibly this ability to fail without tripping it's protections "may" be why they are being sold for a reduced price.

The failure is not as far as I can tell any risk to users of the device it just might mean that heavy users of the device might moan at ASDA! However if the 2.1A limit is observed then the packs should perform very well for the price.

Peter
G4DCP