I was reading an article about why you shouldn't daisy chain UPSs. Initially, I couldn't understand why this was even article worthy. I'm thinking who in their right mind would do that. Then I thought maybe someone had leftover UPSs from a downsized company.
It's finanacially smarter to buy the UPS you need than two half the runtime. On a 120V battery, 2 hours might cost you 40$ whereas 10 hours might only cost you another 20$ more. It's a no-brainer to go for the 10 hour. I know you can find them cheaper than this, but i am talking in "for instance."
Ok, but supposing you had a big stockpile of UPSs that weren't been used anymore. Can you daisy-chain them? The answer is yes, you CAN but why would you want to. Here's three reasons why you shouldn't.
- First, it's not UL recommended.
- Second, you're not going to get 4 hours off 2 2-hour UPSs. Once the electric cuts, the UPSs sense that the electric is cut and you'll be using both UPSs at the same time.
- Lastly, do you really want to listen to beeping for more than 2 hours?
The electric cut at my work last week. Maryland has had a record amount of rain. The reservoirs are full. The trees are falling over and power lines go SNAP! My UPS kicked it and let me tell you I didn't even make it 2 hours and the beeping drove me nuts i powered off my UPS. The UPSs kept the servers up long enough to get the generator turned on. No one sits in the server room so no one listens to all that racket.
So basically, if you have a stockpile of UPSs, put them on ebay or donate them.