APC Backup-UPS Questions

[eXzenTrix]

Hello Everyone,

I've recently come across a bunch of used UPSes when a local office was closing down. After a lot of hauling (and they are heavy!!!..lol) I've dragged a good number of them to my garage and I plan on putting them to use. I have no idea if the batteries are good or not which leads me to my first question. Whats a good way to test them? My plan was to take them all apart and hook up ALL the batteries in series then reconnect some of the controls and inverters etc. and put them to good use. Is this a feasible thing to do and what components will I have to replace in order to accommodate the higher current?

Thank you

 

[eXzenTrix]

Bump

Anyone with input please help. Much appreciated

 

[crutschow]

What are you going to do with all the batteries connected in series? The high voltage will blow the inverter circuits of the UPSes. It would probably take some serious redesign of the circuits to accommodate a higher current (larger power transistors, bigger transformers, bigger heat sinks, etc.) and likely cost more than buying a new larger UPS.

 

[draeath]

You might be better just pulling the sealed lead-acid batteries out. Think of them as miniature car batteries, and go from there. You could probably use them to power a coilgun!

 

[eXzenTrix]

Thnx for the replies. My main purpose was to simply get more down time power for a lot more computer equipment. I'm currently using a 3 tower setup with some (500W PS, 750W PS, and an 1100W PS on my new rig) and am working on a project to setup an 11 LCD screen video wall. All those electronics are pulling a lot of power and I'd rather not buy any commercial grade PSUs since I have all these regular ones to play around with. I always did like to involve myself in a project or two, so I figured why not. But I guess the first step is to figure out which of those batteries are still good. Please advise of the best way to go about that.

 

[eXzenTrix]

You might be better just pulling the sealed lead-acid batteries out. Think of them as miniature car batteries, and go from there. You could probably use them to power a coilgun!

Hrm...a coilgun... now that would be fun

 

[Noggin]

As stated, don't put the batteries in series as you'll damage the UPS circuits. The next thought is to put them in parallel. You can't do this either. If one battery is at 12.2 volts and the one next to it is "dead" at 9v, it'll put a massive drain on the good battery. Even if the second battery is as 12.0v it'll put a drain on it.

General rule of thumb, batteries never go in parallel without some way of balancing them.

The best thing you can do for yourself is plug in the UPSs for a day or so and let the batteries charge. Pull the batteries and measure the voltage. If any of them are blow about 10.5v, its bad. Let the batteries sit for a week and measure again. Then put a light load on the batteries for a few hours and measure again.

Consider it a project to save yourself from headaches in the future

 

[HarveyH42]

APC says the batteries need to be replace every 2-3 years. I get 5-6 years, but don't lose power often or for long periods. A new battery is around $40.

A 400w UPS can provide 400w for 20-30 minutes. It won't power an 800 watt coffee maker during a hurricane (tried it), shuts down. Don't think it will let you exceed the wattage rating. Might get away with higher capacity batteries for more run time though.

I saw a hack once for increasing the output of a car inverter, by replacing the power mosfets, not sure if that would work in a UPS though...