UPS Hacking in Hurricane Season?

kengreenebaum asks: "Perhaps not the most exciting of topic; however it is storm season and I have a couple of UPS's that need new batteries. What is the best source for high quality, long lived replacement batteries for these devices? I assume it takes a special chemistry to survive continuous trickle charging and an occasional deep cycle. Has anybody tried connecting larger capacity batteries external to the UPS enclosure to attempt longer run times? (Obviously the load capacity is based on the inverter itself and can't easily be modified) Also what software do you use for monitoring and automatic shutdown on Linux? I have collected quite a few APC and Belkin UPS's 700VA or smaller as they go on rebate/sale."

Comments

Not sure if entire relavent

[Student_Tech]

For the batteries, if it is maintaining the voltage at a "float voltage" the batteries can be held nearly indefintly without a discharge or worry of overcharging. Lead acids have a float voltage of about 2.35 volts/cel (based on some quick googling). They will still die after some time.
But I don't know what technology, size, or how the UPSes actually using the batteries.
If I was DIY a UPS, I would have about 10 12Volt batteries (no transformers...), drive them off a full-wave rectifier, filter the power from the rectifier a bit, and then invert the power to make it back to AC and use my equipment off that. Advantage, I am always off the batteries, disadvantage, I have no monitoring ability and if I was to set the incoming voltage to the float voltage, it will probably take a while to charge.

Re:Not sure if entire relavent

[spikestabber]

I've ran computer switching power supplies off of 110V DC (Direct current) before. Since their internal switching unit does not need the alternating current anyways. The AC is just converted to DC and filtered with a couple large capacitors, so feeding it DC will work just fine.

Re:UPS' Contain Standard Gel / Sealed Batteries

[nuxx]

Here's the thing... I *think* you could, but unless you properly take into account the amperage of the batteries and such, you could risk damage to the circuitry which handles the switching. And that would be bad...

That reminds me of how once when working retail, this guy came in and asked me how many deep cycle batteries he could chain off an APC BackUPS. He wanted literally racks and racks of them, so that he could handle his whole house. All while having things switched by that little BackUPS...

I'm not sure if you've ever been in a server room, but the UPS' to handle switching massive loads like this tend to be multiple-rack-sized, having contacts that look more like copper paperback books jutting out of the panel.

Re:Experienced advice

[fm6]

...the term UPS can refer to a pussy office UPS thats basicly a bloated power strip, or it can refer to a building full of batteries capable of running a large factory for an hour.

At the server farm where I work, it refers to a room full of lead-acid batteries that are capable (so management claims) of powering all 10,000 systems for 14 hours, plus a diesel generator. In fact, server farms are a major air quality problem in Silicon Valley, 'cause whenever there's a brown- or blackout, dozens of them fire up their diesels, pouring an ungodly amount of particulate in the air.

Re:UPS on the cheap

[stvangel]

Okay, I have no idea how that got submitted. Must have been a UPS glitch. :)

What I was saying was, I use "broken" UPS with used batteries that I can get for next to nothing. Old car batteries have worked well for me. I charge them up fully with a normal car battery charger before I hook them up to the UPS guts. Even if they can't provide the surge to start a car anymore, they can still usually provide enough power to run the computer through a few-second glitch and a minute or two shutdown. Even if I have to replace them once every couple of years, they haven't really cost me anything in the first place.

I just want the UPS to carry me through the few second brownout or outtage. If the power is out for more than 10 seconds, chances are it's going to be off for a while and I trigger the shutdown on the systems. I don't plug the monitors into the UPSs because 21" monitors take too much current draw and why bother leaving them on just to watch the shutdown. I've been using a half-dozen UPS like this for 10 years now, and haven't spent more than $100 or so total.

Having said that, I have one Main server that runs on a normal UPS that can keep it, the main router, and the internet link up for an hour. This -does- need to stay up because it's too much of a pain to restart everything. Everything else can shut off until the power resumes.