Hacker News Reader

Another important point is that an UPS can produce huge surge currents, for example when switching from battery to utility. The upstream load goes from zero to the sum of both the protected load and the UPS charging its battery.

When daisy-chaining an UPS to another, the downstream UPS can easily overload and trip the upstream UPS because of that.

View on HN

Wow. Your post is much more informative and clearer than the article. And it's only three sentences.

> Another important point is that an UPS can produce huge surge currents, for example when switching from battery to utility.

It has not happened yet. If downstream UPS likes the source, it is not going to switch to battery, and battery charging will Not be happening because downstream UPS had it charged already long time ago.

An easy fix for that would be to put a surge protector between the UPSs. (Joke)

------------

I bought three UPSs, all them used independently; but I had to stop using all of them. They all had a capacitor whine that was driving me crazy.

Reply on news.ycombinator.com