Is it possible to use a large-capacity USB-connected battery as a UPS (uninterruptible power supply)?

Among the mobile batteries that charge and supply power with a USB connection, there are those that support 'pass-through charging' that allows you to charge smartphones and tablets while charging the battery itself. Dr. Gough Lui of IT blog Gough's Tech Zone explains whether it is possible to keep the USB-connected battery equipped with this function constantly charged and use it as a UPS (uninterruptible power supply).

Note: Potential Issues of Using a USB Powerbank as a UPS | Gough's Tech Zone

The short answer, Gough says, is 'it depends on luck.'

One of the reasons is that there are almost no products that state whether they can be used as UPS in the first place. Because you can also give.

Mr. Gough gave an example of a mobile battery called '

The manufacturer's website does not specify whether pass-through charging is supported, but the data sheet for the chip iSmartware SW6208 used states that it supports charging the battery and supplying power to an external device at the same time. Charging)' and that it is compatible with pass-through charging.

In addition, it can be disabled if not needed, only 5V input/output is supported when using 2 or 3 ports, and the charging current decreases when the input voltage drops, so the input voltage can be held at 4.8V and external devices There is an explanation that priority is given to supply to

When Mr. Gough tried using the actual machine, there was a timing when the output was interrupted even with a battery that supports pass-through charging.

Also, even with a 'mobile battery with uninterrupted output' that overcomes this issue, the charger usually has a safety timeout of 8 hours to less than 40 hours, which may cause a partial short circuit. It is designed not to keep charging a certain cell, and it seems that the charging rate may be less than the depletion rate.

In addition, since mobile batteries using lithium-ion batteries and lithium-polymer batteries are designed to prioritize extracting maximum capacity from the cells, they are inherently under high stress, and cell capacity deteriorates rapidly. He said he would.

From this information, Mr. Gough concludes that although there is a mobile battery that can be used as a UPS, there is a high possibility that it will encounter some problems, and it is not recommended to use it for a long time without being able to see it. .