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Do-it-yourself UPS
Giampiero writes "Over at dansdata.com some guy named Dan creates a UPS out of some spare parts. To sum it up, "if you're looking for an industrial-capacity UPS solution, and don't like the prices of the off-the-peg options, it might be easier than you think to roll your own."" Of course you can mentally substitute U.S. 110 volts for Australian 220 volts wherever necessary...
Please, everyone take caution when working with high voltage and moreso, high ampre compenents. We don't want any fried ./ers
Tibbon
tibbon.com
Oh ... um ... never mind.
I've been doing this for years. I have a big brown truck, and whenever I want to send something to someone else, I just put it in a box, hop in the truck, and drive it over to them. I've even got a little portable touchpad for them to sign on, so it feels like the real thing.
TheFrood
If you say "I'll probably get modded down for this..." then I will mod you down.
On the other hand, would I get to wear the little shorts? Chicks seem to dig those.
---- El diablo esta en mis pantalones! Mire, mire!
Of course, PCs don't actually use AC power: there's a big box in the back that converts all the AC input back to DC. So why not save some money and bypass this, by running the PC straight off the battery (like a laptop)?
Coupla caveats:
.3 or .7 volts.
Put a "battery isolator", or at least a power diode with a heat sink, between the power supply and the battery. And allow for the fact that it will drop
Don't even think about wet cells inside the house. Sulfuric acid belongs out of doors. There's a reason you're allowed to ship the Concorde battery without declaring it hazardous: it won't spill. Further, a non-sealed battery will release hydrogen while it's being recharged. Is your computer room free of all ignition sources?
Fred KC7YRN
(I've seen a commercial 500 VA unit for US$40)
When I did tech support for Gateway I got a guy who worked for APC, he had a UPS on his Fridge, his microwave, his TV, his stereo, and his pc but forgot to protect his phone line, Lightning struck by his house and took out his modem, along with his mobo. After he told me all that I laughed so hard he hung up, I wonder what ever happened to him, hehe
It's not the OS it's the user that sucks. If it's user friendly, you get stupider people. - clinko
These do-it-yourself UPS thingies are going to require maintenance. Car batteries are designed to deliver about 3400 amps directly into the alternator of a car, only during the time that you turn the key. They they trickle charge very slowly off the engine mains.
By contrast, UPS batteries are designed to discharge at a slower rate, but charge very very quickly to be able to work if the power suddenly cuts out two or more times in a row.
The problem with using one battery where another is required is that a memory effect can develop. That slow discharge on a car battery can cause it to lose capacity and in as little as 6 months it'll be useless for any power failures over about 5 seconds.
How much does a car battery cost? about $50. But, you're going to need one every 6 months or so, making a home built UPS actually many times more expensive than one you buy at Comp USA.
I know it's counter-intuitive, but many things about batteries are.
If tits were wings it'd be flying around.
$1.00 AUD = $.56 USD = €.60 EUR
Be careful with this stuff. Batteries can be nasty. At my previous job we had a "switch room" which housed out 50,000kva (yes "K"va) UPS. On the wall across from it were huge "grab the handle and yank" circuit breakers...which were covered in battery acid from the previous UPS.
Now this wasn't your home little ups box, this thing would blend in with three refrigerators side by side, and would run a 500 person electronics factory, and 500 person office (PC's at least) for 8+ hours. That was a kickass battery box.
Just remember, UPS's can go "BOOM" and I wouldn't want to try my hand at making my own and seeing it for myself. Some things are better left to APC and crue.
-Pete
Soccer Goal Plans
Comment removed based on user account deletion
However, you can probably replace the battery in your UPS with a similar model for less than the cost of a new UPS. Either find the manual for your UPS, search for your UPS model on line, or open up your UPS and see if it has any labelling regarding the battery capacity, or (better) a "replace battery with XXXXXX model or equivalent." Find an equivalent on line (thanks, Google!)
Check with a battery store (most major metropolitan areas will have several.) It may be worth the drive, as batteries are heavy, cost much to ship, and can only be delivered via ground (slowly.) And if you're uncomfortable working with live circuits or very hazardous materials, they'll probably be able to replace it for you for a small fee.
Finally, PLEASE RECYCLE YOUR OLD BATTERY! In most states, it is illegal to dispose of any lead acid batteries in the garbage or in a landfill. They are filled with corrosive toxic sludge. Please be responsible.
John
Or, you could visit:
http://auction.apc.com/
And get refurbished, and sometimes brand-new, warranteed APC power units for pennies on the dollar.
Two years ago I purchased two 420VA refurbished backups for around $50 each. They're currently protecting my three boxen, one of which I'm on now, and have been flawlessly through brown-outs, sags, surges, etc.
Typically the refurb'd units are from companies who have agreements with APC to buy many UPSs and return them when the batteries run out. Why? Customers used to return UPSs marked as 'defective' when in fact it was simply a dead battery. So, they tape over the battery bay and simply have the customers return the units with dead batteries and pick up a new one. They replace the battery and sell the ok unit again as refurbished.
Thanks,
--
Matt
I've even got a little portable touchpad for them to sign on, so it feels like the real thing.
If you really want it to feel like UPS Ground, shouldn't you kick the box around the back of the truck en route?
"We returned the General to El Salvador, or maybe Guatemala, it's difficult to tell from 10,000 feet"
Totaly myth.
Not possible.
Even if the resistance was only 1000 ohms, and it was most certainly a great deal higher, he would only have 9 mA, not 80.
I have two UPSes -- I used to have three but one died a horrible death for no apparent reason.
:-(
The smallest unit I have is a 600VA no-name Taiwanese box with two 7A SLAs. It has no fan and, although it's just an SBS, it still runs hot as hell.
As a result of this hot running, I discovered that the SLAs tend to dry out rather quickly such that you get a much shorter time than you'd expect when the mains power goes off (as I discovered just the other night
My other box is a Siemens 1KVA full-time UPS with forced ventilation and a bunch of other cool features.
It's worth noting that even a fan-cooled UPS such as the Siemens can run way too hot -- as I discovered about a year after I installed it.
Without warning, the UPS started screeming at me with a continuous alarm buzzer. It was still working but it was not at all happy.
On touching the case I discovered why -- it was too hot to touch.
I shut things down really quickly and opened up the case to see what was wrong...
Dust!
The intake holes in the front panel have a fine wire mesh over them and, since this UPS (like most others) lives on the floor under my desk, enough dust had been sucked into the holes to totally block them.
So here's a DC-AC inverter busy delivering about 500W of power to several computers and monitors -- but without the benefit of any cooling. No wonder it wasn't happy.
I blew the filters out with compressed air, checked that the fan was okay and put it back together. It's been working fine for nearly two years since -- albeit that I check and clean the intake meshes every few months now.
That the Siemens box was smart enough to warn me it was in distress (rather than just failing) shows that nobody ever regretted buying quality.
So.. rules of thumb for UPSes...
If it runs hot-- expect the batteries to last just 18 months to 2 years -- and don't wait until the power fails to find out that you should have changed them already.
If you have a fan-cooled UPS mount it up off the floor or check that the cooling holes are clear at regular intervals.
I did some network consulting at a lawfirm that had offices in a high-rise tower. They couldn't get the EPA permits granted for a diesel powered backup generator, so they built a "UPS" room.
The inverter came from these guys here.
They hooked up half a room full of 12 volt lead-acid batteries to charging systems and inverters and put the whole system under a vent hood. We never did figure out exactly how much runtime their server room had.
-ted
To a large extent the danger of explosion can be reduced by using hydrogen catalyst battery caps on all cells of the lead acid battery. These can be purchased from Hydrocap, 975 N.W. 95 Street, Miami Florida, 33150,(305)696-2504.
M0571y H@rml355.
UPS batteries tend not to be as expensive as notebook batteries...there aren't as many different varieties, so they tend to be somewhat standardized. I recently replaced the two 12V 7Ah batteries in a UPS at home. That UPS cost about $170 when I bought it. New batteries were about $40 for two. Given that the UPS is a 900VA unit that can keep a dual-P!!! server running for about half an hour, $40 isn't a bad deal to keep it running.
20 January 2017: the End of an Error.
At work we bought a 3kva upsonic ups. Its good for about 10 minutes. That just would not do so we hooked up 16 deep cycle batteries to the thing. Now it will run for about 4 hours on a full load and a very long time when we start pulling things offline. It takes 4 days to recharge the thing.
We got a UPS because it has a good inverter and auto switching and a built in charger. An inverter would have cost more. I've got a snmp card so I can measure different things.
You have to be careful about these things beause you get a large voltage and massive amounts of current. Our system has two 96 volt banks and good for at least 300 amps. That can kill and it can also cause batteries to explode. Treat these with the respect they deserve. We have a small circut that goes between each battery that has 4 led's that let us know if any one of the batteries go bad. Its also hooked to a monitor system so we can get real time alarms if anything goes bad.