We put supercapacitors in the UPS instead of the battery

Anyone who has an uninterruptible power supply (UPS) for a computer at home knows its one significant drawback, which costs its owner a pretty penny. This is, of course, the fragility of its batteries. Usually, if you're lucky, they live for 3 years and then lose their capacity and functionality. This eliminates the possibility of using the UPS directly for its intended purpose.

Almost all UPS systems use sealed, maintenance-free lead-acid batteries. The very word “maintenance-free” makes it clear that it is impossible to restore such a battery, and if it is possible, it will certainly not be for long. And then the idea came up to replace the battery with supercapacitors (ionistors). They have an enormous service life, are absolutely tolerant of high loads, the number of charge-discharge cycles is more than 10,000. Therefore, if you are lucky, the uninterruptible power supply will become eternal!

Will need

6 supercapacitors with balance protection board. You can buy ready-made at AliExpress.

The balance protection board is a mandatory element. Operation without it ionistors in a series circuit is impossible, since everything is fraught with failure of any element during recharging.
The capacity of 1 element in the circuit is 500 Farads and the voltage is 2.7 V. That is, 6 pieces will make up a battery that can be charged to a maximum of 16.2 V.

Replacing the battery in an uninterruptible power supply with supercapacitors

In theory, as always, everything is smooth, but in practice everything is not as we would like.

In this example, a UPS was used that had a maximum load power of 300 W. It removed the non-working battery and installed a board with supercapacitors instead of the battery.
First start. And then the first failure: the UPS, of course, turned on, but charging ionistors refused. Why? The fact is that the UPS circuit had protection that did not allow charging if the initial battery voltage was less than 10 V.
Second attempt. Then I took a third-party adapter with an output voltage of 10 V and simply charged the capacitors before turning it on.

I turned on the UPS and everything finally worked. Ionistors continued charging to the threshold voltage of the acid battery.

As a result, it was decided to remove the low voltage protection by modifying the UPS circuit.
But these are not all the pitfalls. Next, the operating time was checked when the network power was turned off. And the results are quite specific. The UPS stopped working when the voltage on the ionistors dropped below 10 V

As a result, the total operating time, depending on the load power, could range from 5 to 30 seconds. Although the load that this UPS previously fed was not very powerful, its operating time was 18 seconds. In principle, this time was quite enough for my tasks.

Installation in the case

It was impossible to install this line in place of the standard battery.The solution was to make a cut in the side of the body and bring the elements out.


As a result, the appearance was not particularly terrible, given that the UPS is located in a secluded place.

As it turned out, the idea worked quite well. Of course, the capacitor capacity must be significantly increased in order to achieve a significant increase in operating time in the event of a shutdown.
Although there is a downside to this coin: as the total capacity increases, the total initial charging time will also increase... which will negatively affect ease of use.

Watch the video

For a complete modernization of the UPS with adjustments to the protection circuits, see the author’s video.