I have a low power NAS (~35W) and I want to buy an UPS (uninterruptible power supply) to keep things running. The problem is most UPS for well known brands have an idle power usage (even without load) greater than 20W. It’s comprable with the NAS + HDDs + Network equipment…
Do you know any alternative? UPS battery for 10 minutes will be enough. UPS load could be very low < 50 W. UPS software is optional.
The UPS has to cycle the battery for its health. This takes power. The 20W will be the recharge.
There is nothing you can do about that. If you DIY your own, without putting battery healthcare. It will fail when you actually need it. And sometimes catastrophically.
I understand. There are Anker power banks for laptops with 65w. They should be more efficient but I don’t have data about the long term use. I guess the battery will last less than the UPS batteries.
Those will not be UPSs they will be power banks. Most Powerbanks are lithium. Lithium requires careful monitoring if it is constantly float charged. And they fail catastrophically when over charged.