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kirkswig

Oct 26, 2004, 9:31 PM

Post #1 of 14 (964 views)

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Building my own uninterruptible power supply (a really big one)

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OK, here's my situation. I'm in an apartment that I just adore, but which doesn't have grounded outlets. This is more than a nuisance for me, as the power will cut out here pretty regularly, and I have a number of computers that I'd like to leave on most of the time, and I can't get either of my existing UPS's to work with this electrical system (they complain that there is a wiring fault, then refuse to work.)

I've done a good deal of research on the web on the subject of adding grounding to an electrical system after-the-fact, and it isn't very encouraging. The apartment is basically built out of brick, and it appears that it would be very difficult to do this without making a major construction project out of it.

So what I was wondering was this: why not build my own UPS? I'm not happy with the duration my existing UPS's would otherwise be able to provide anyways... often times the power will cut out in the middle of the night and there is the obnoxious alarm sound these things make and I'd rather not have to be fooling around with shutting down my computers so late anyways.

Ideally, what I would have would be something that could power my computers for hours, not minutes, when the power goes off. It would be continuously charged when power was available. However, the tricky thing here is that the computers couldn't be connected directly to the building's electrical system. Is that possible? In other words, even while the batteries are charging (i.e., AC is available) I would want the computers to be powered from the batteries themselves.

I'm hoping that by doing it this way, I will insulate the computers against voltage fluctuations/spikes/etc., obliviating the need for a ground, while enjoying 24/7 power availablity, at least for the computers.

I'm trying to find the answer for myself, but it really does appear that I'm going to have to get fully up-to-speed on how electrical systems work before I can start this. I'm not asking for detailed instructions on how I would do this, but rather, just a general sense of whether what I'm trying to do is feasable or not?

I like to think of it as running my computers as if I were on a boat. Only instead of using wind/solar/diesel generators to top off my batteries, I'd be using AC.

Can I do this?

To boldly go where no wig has gone before.

sfmacaws

Oct 27, 2004, 9:36 PM

Post #2 of 14 (933 views)

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Re: [kirkswig] Building my own uninterruptible power supply (a really big one)

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What you want to do is very similar to what we have in an RV so I'll take a stab at this. Your UPS will be 12v and consist of batteries. You want Deep Cycle batteries probably something like 6v golf cart batteries wired in series, these are made for long sustained drains and not for huge power surges as in starting a car. Between these batteries and the AC power of your apt you will need a converter/charger. These come in many flavors but the basic ones just convert 120vAC to 12vDC. The charging part of it is usually either 2 stage or 3 stage. The difference is how efficiently it tops off the batteries and whether or not you can use it to equalize the batteries. Magnatec makes servicable ones for RV systems. There are better ones but you might not need it.

How you figure out how many batteries will depend on your draw. Add up the amp hours of all of your computers running for the length of time you'll need - I'd guess 1 day would do it. 2 6v batts wired in serial will give you a max of 225AH - reality will be less than that.

Now you have to plug all your stuff into the batteries. Unless you have 12v plugs for all of it (doubtful) then you will also need an inverter that can handle the load. An inverter turns 12v DC into 120v AC. So, you are going to be switching AC to DC and then back to AC with a loss at each conversion. Size the inverter slightly higher than the load you will be plugging into it. Inverters work best at near max load, the lower the load the less efficient they are.

Some thoughts. you'll need sealed batteries - AGM probably - and they are expensive. To use the cheaper lead acid batteries you will need to put them outside or in a well ventilated space. You don't want to live with open cell batteries.

Your converter will need to be capable of handling the normal voltage where you are. In our part of Mexico (QR) voltage is regularly over 130v. Check this out carefully in the converter specs.

It will be interesting if you build it - no doubt there will be a considerable initial expense. As I said, you are reproducing a setup similar to an RV in that most systems are powered by 12v from the batteries and the batts are recharged when connected to shore power by a converter. You could also decide to put some solar panels on the roof and recharge the batteries that way thus bypassing CFE completely.

If you do it, please detail it all here.

Jonna - Mérida, Yucatán

kirkswig

Oct 28, 2004, 10:23 PM

Post #3 of 14 (899 views)

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Re: [sfmacaws] Building my own uninterruptible power supply (a really big one)

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This is a great reply, thank you very much.

I'm willing to spend some big bucks up front to get this to work. Safe and always available power for my computers is worth it.

Now, if you will indulge one more question...

The converter/charger that takes the AC from my apartment and uses it to charge the batteries, what happens if, say, a voltage spike occurs?

The UPS I have now would send that electricity to ground, right? Thus sparing my computers from damage. Or at least, that's the way I understand it.

How does the converter/charger protect my computers if it has no way of "spilling" any excess current?

Here, let me make it easier to answer. Multiple choice. Please bear in mind I don't know what I'm talking about...

If a lightning bolt hits and a massive charge is set to my outlets, which of the following occurs:

a) The converter/charger gets fried.

b) The batteries blow up (or suffer some other malady.)

c) My computer(s) take the hit.

d) None of the above.

e) All of the above.

The good news is that my apartment sits in the shadow of these massive radio/TV antenna/tower things that attract all of the lightning within a half-mile radius. So worrying about power spikes of the kind that lightning can produce may be unjustified paranoia on my part.

The bad news is that the power grid here is otherwise wacky enough to have sent an otherwise reliable UPS to its grave. Again, I have no ground here, but the docs for my UPS say that the UPS should still be usable, that it just won't be able to protect against power surges without the ground, and yet, the battery part of the UPS is totally fried (aka, not operating.)

---

OK, nevermind, I'm reading this post and I'm asking for a really big answer, and you've already given me one. I am going to pursue this (and of course, I will post the results here.) I will budget $1000US for the batteries and equipment, and see what kind of mileage that will give me. For truly clean and reliable power, it's worth it. My Athlon PC (the Windows box) has only recently been re-assembled (partly), and as yet hasn't been treated to a power outage, but my Power Mac has now suffered *many* outages, and I'm worried about it. It's hanging in there like a champ, but still, I have to believe that bit rot is setting in.

If I were running Mac OS 9 (or earlier), I'd probably have reformatted and reinstalled at least twice by now.

To boldly go where no wig has gone before.

sfmacaws

Oct 29, 2004, 3:55 AM

Post #4 of 14 (893 views)

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Re: [kirkswig] Building my own uninterruptible power supply (a really big one)

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If your UPS isn't grounded (no ground plug) then it wouldn't be able to ground anything. In reality, if you get a big surge to a UPS with a surge protector it will probably fry the UPS anyway. I think the best you can hope for with an average surge protector is that it commits suicide to keep the surge from passing through to your equipment. I don't think there are commercially available surge protectors (at least for less than a govt size cost) that can protect from a lightening strike. Think of the power and size of that, it would fuse whatever it hits.

I may be wrong but I think that most surge protectors are designed to protect you from the surge that commonly happens when the power has been out and comes back on. I would put a plain surge protector in front of your convertor. If it suicides, get another one.

Quote

If a lightning bolt hits and a massive charge is set to my outlets, which of the following occurs:

a) The converter/charger gets fried.

b) The batteries blow up (or suffer some other malady.)

c) My computer(s) take the hit.

d) None of the above.

e) All of the above.

Well, a) for sure if it's first in line. b) maybe. depends probably on what is closest to the plug. If there is an easy ground near the plug or the converter (like you have a hold of it) then it would probably send most of the juice that way. But, lightening is so powerful that it would no doubt burn down the apt house as well. If it's just a powerful surge coming down the electric line then it might just stop with the batteries. I'm on shaky ground here, I'll admit to guessing on this. c)I doubt they would be hit but see previous.

Quote

The bad news is that the power grid here is otherwise wacky enough to have sent an otherwise reliable UPS to its grave. Again, I have no ground here, but the docs for my UPS say that the UPS should still be usable, that it just won't be able to protect against power surges without the ground, and yet, the battery part of the UPS is totally fried (aka, not operating.)

It sounds like when the surge protector fried, the batteries got hit as well. You will need to do some more research on this as I'm not sure what protections are in the UPS or how high voltage effects batteries.

We have a $300 gadget that plugs between our RV and the AC power. It will shut off the power if it gets too high (or too low, brownout) and test until it is back within the set parameters and then allow power through again. I've heard that it is good for small surges but that there are better plain surge protectors out there. Perhaps something like this would save your converter/charger and batteries from more normal surges and then go back on and continue charging.

This is a recommended site http://www.amplepower.com here's another one http://www.exeltech.com

For some basic 12v info as it relates to RVs go to Phred's Poop Sheets http://www.phrannie.org/phredex.html
He talks about battery chargers, surge protectors and UPS in there and he is well respected and easy to read.

Personally, I stick to laptops and hope that the invertor in the 12v cord will protect them. So far so good. It helps that I don't have to leave them plugged in all the time.

Jonna - Mérida, Yucatán

johnv

Oct 29, 2004, 6:34 AM

Post #5 of 14 (888 views)

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Re: [kirkswig] Building my own uninterruptible power supply (a really big one)

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I'm a little confused. I'm sure that 99% of Mexico goes without uninterruptable power supplies. I know that I have been doing without one for 2½ years and have had surges, brownouts, electrical failures, lightning storms, etc. My computer is still functioning just fine. It is grounded. I installed a 3-prong receptacle, drilled a hole through the masonary to the outside, ran the ground wire, and attached it to a 3 foot bronze rod driven into the ground. I also use the surge suppresor that came with the computer, and a Mexican voltage regulator. This is all very interesting about how to create an uninterruptable power supply, but is it nesessary? What is bit rot? I've never heard of it.

kirkswig

Oct 30, 2004, 12:33 AM

Post #6 of 14 (864 views)

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Re: [sfmacaws] Building my own uninterruptible power supply (a really big one)

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OK I think I'm on the right track now. Thanks so much (again) for your help.

To boldly go where no wig has gone before.

kirkswig

Oct 30, 2004, 12:51 AM

Post #7 of 14 (864 views)

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Re: [johnv] Building my own uninterruptible power supply (a really big one)

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Bit rot is, um, well, an informal term that some use to describe entropy in a computer system.

Basically, it's like this. As computers run, errors occur. Errors begat other errors. Eventually, the entire system comes crashing to a halt.

Now, when the power gets cut out, this process is greatly accelerated. All kinds of bad things can happen. Stuff that should've been written to disk isn't. That can be a report you were working on, or, it could be the disk block that is part of the extent file used to keep track of the files on your system.

That said, the newer operating systems seem to be very good at staving off the effects of bit rot. I have been very impressed with Mac OS X since arriving in Mexico. It has taken a considerable beating, and yet everything appears to be functioning perfectly. I have a similar impression of Windows XP, though I haven't as yet subjected it to the same kind of punishment (I've only recently starting using that system since arriving in Mexico.)

Some perspective... I spent about 15 years using the pre-OS X versions of Macintosh. I would do software development on these machines. The odds were about 1-in-5 that when the program I was writing crashed, the system would crash. The odds were about 1-in-7 that when the system crashed, I would need to reformat and reinstall the OS and all my tools and files. So it may very well be that I am fatalistic when it comes to bit rot.

Some habits die hard.

To boldly go where no wig has gone before.

sfmacaws

Oct 30, 2004, 3:17 AM

Post #8 of 14 (863 views)

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Re: [kirkswig] Building my own uninterruptible power supply (a really big one)

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Kirk,

There is something else you should think about it keeping your electronics running over time and that is salt air and humidity. In the Yucatan, keeping electronics in an un-air conditioned room will really speed up their demise. Stuff corrodes within a year and starts to fail. I don't know if you will have the same problems in Maz or if you are close enough to the ocean for it to be a factor. It's a big consideration for me, I wouldn't bring a desktop down and leave it at my place on the caribbean because of it. Everything corrodes, boom boxes, tv's, refrigerators, VCRs, stuff sealed in plastic containers, whatever... whereever. The salt and the humidity can get into anything. The smaller and more delicate the part, the quicker it gets covered with corrosion. If you don't AC the room your computers are in then you should get a dehumidifier and run it all the time.

Jonna - Mérida, Yucatán

raferguson

Nov 20, 2004, 9:21 AM

Post #9 of 14 (810 views)

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Re: [kirkswig] Building my own uninterruptible power supply (a really big one)

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A lot of good discussion.

One of the things that fries electronics is voltage differential. Let's say that you have a computer connected to a phone line and to AC power. Let's imagine that a lightning or other surge hits the phone line, but not the AC, or vice-versa. This means a huge voltage differential across the computer, which will inevitably get damaged. One way to fight this is to connect everything (phone and power) through the same surge protector. That way, the surge protector shunts the surge to ground, and keeps the computer from being the shunt. In fact, I have been told that if all the wires going into the computer go up 1000V or more, but they all go up and down together, there will be no damage to the computer.

You don't need to be too creative to build a UPS system, a battery charger, a battery bank, and an inverter will do it. Just buy good ones. Two large 6V deep cycle batteries would be good. An electrical engineer friend of mine uses such a system when he operates equipment on generator power in remote places, given that generators are even less reliable than Mexican power. ;-) Just be sure to put a surge protector between the inverter and the computer, and tie the phone line through the surge protector. If you have a cable modem, plug the cable modem into the same surge protector, and get a surge protector that will protect coax cable. For my DSL system, I tried to protect my ethernet cable as well, but for some reason, the surge protector screwed up the ethernet connection, so I had to forget that idea. At least the ethernet does not leave the house, so less likely to pick up surges.

By the way, if you replace the two prong outlet with a three prong outlet, and then tie the neutral wire to ground, the UPS will think that the outlet is a good one. If you do this, it would probably be best to use a GFI outlet. Also, be sure to verify which is "hot" and which is "neutral", You would need to find a true ground to be sure, maybe the water pipes are grounded if they are copper.

Richard

http://www.fergusonsculpture.com

kirkswig

Nov 23, 2004, 12:38 PM

Post #10 of 14 (781 views)

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Re: [raferguson] Building my own uninterruptible power supply (a really big one)

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Any kind of surge protector depends on having a ground, right? So unless I have a electrician come over (assuming I can secure landlord approval) and perform what I think will be a massive undertaking I will be unable to take advantage of surge protection.

Then again, as I've stated before, I live in the shadow of these immense radio/television towers which act to collect all of the lightning in the immediate area.

Now, the DSL/phone connection should be OK, provided I'm getting power from the battery bank, right? I mean, there's really no differential there. If say a power spike did occur on the phone line, there's no place for it to go since the only other connection is to my bank of batteries, yes?

I'm still shopping around for the charger/batteries/inverter. It's a bit of a challenge in Mexico when you don't speak Spanish. Just to be thorough, I will investigate the possibility of adding the ground too.

Thanks for the info.

To boldly go where no wig has gone before.

johnv

Nov 23, 2004, 8:44 PM

Post #11 of 14 (764 views)

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Re: [kirkswig] Building my own uninterruptible power supply (a really big one)

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I grounded the outlet that my computer equipment plugs into, and it was rather simple, cheap, and uncomplicated, and required neither an electrician, nor land-lord approval.
Parts: Double receptacle, three pronged US$3
Heavy duty wire, 6 ft. US$1
Bronze Rod, 4 ft.,(from junkyard) US$2
Wire Clamp US$1
Tools: Hand drill
10 inch masonary drill bit
Screw driver
Adjustable wrench
Hammer
Circuit ground tester
Instructions:
*Remove the existing 2 prong receptacle
*Drill a hole from in back of where the recepacle
was,through the wall to the outside of the
building.
*poke the heavy wire through the hole
*hook up the 3 pronged receptacle, with ground wire
*Drive the bronze rod into the ground or drill
a hole through the masonary and then drive it into
ground.
*clamp the heavy ground wire to the rod.
*check ground by plugging the circuit ground tester
into the recepatcle. If the 2 yellow lights go on
indicating "correct", your done.
Total Cost: US$7 (+US$8 if you have to buy the circuit
ground tester)
Total Time: Less than an hour if your apt.
If not, up to 3 hours.

kirkswig

Nov 24, 2004, 9:28 PM

Post #12 of 14 (739 views)

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Re: [johnv] Building my own uninterruptible power supply (a really big one)

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I guess that sounds right if you live in a house or at ground level. I'm in a different situation. I'm on the third floor of what could be called a very creatively built colonial apartment house. To the front there is a terrace and a walkway and no opportunity to dangle wires or drive copper stakes into the ground. To the right there is a neighbor. To the left there is a two-story drop to a stone walkway, then a tall fence.

My best/only opportunity would be to the rear, but even this is incredibly complicated. I have a terrace which is a story above another stone walkway, but on the other side there is a backyard of sorts complete with a healthy population of iguanas. However, the landlord is in the process of recreating this back lot into something else... I think a garden.

The amount of work necessary to make this happen would definitely require landlord approval. If for no other reason than the present state of the electrical system here. When the power goes out it does so in a very peculiar way. Some appliances cease to work, while others continue as if nothing happened. I can go up on the roof of the building and see that there isn't a single light on for a block radius. Except for the one in my bedroom and for the front patio.

I guess the issue is more than just having a ground for the outlet. I find the electrical system highly suspect in general. Maybe for the TV and the microwave oven it's fine, but for my computers it just isn't acceptible. During the summer the power either blacks out or browns out at least five times a week; and usually when I'm sleeping. That's a problem because I usually have one of the computers on as I sleep doing things, so the UPS alarm sounds. It's not a friendly sound. My computer administration skills are decent, but not when I'm woken up at 3AM and I only have three minutes of remaining power to make sure everything is correctly shut down.

Or even if it's during the day... it would be nice to blow off these brownouts.

And then there's the possibility that I move to a more remote location in Mexico after acquiring the ability to speak Spanish. The power quality is almost certain to be poorer there than it is here.

Of course, the possibility of lightning strikes would likely increase too, but I think I have that figured out as well. The phone line gets connected to a wireless router. And my LAN gets connected to another wireless router. So my network is never in contact with any wires coming in from the outside, ergo, the chance of damage being inflicted should be very low. Incidentally, this arrangement would essentially be consistent with establishing my own DMZ on the network, or if you will, another layer of protection from the malicious sort of people you will find on the Internet.

Finally, it's also a leg up on exploiting alternate forms of energy. It seems to me that once you have the charger/battery bank/invertor combination set up, the matter of adding solar panels or wind turbines or diesel generators becomes trivial.

So I'm looking at this as a long-term solution too.

To boldly go where no wig has gone before.

johnv

Nov 25, 2004, 9:05 AM

Post #13 of 14 (728 views)

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Re: [kirkswig] Building my own uninterruptible power supply (a really big one)

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I guess your situation is more complicated. I'm sure your residence is beautiful, but personally, I never liked apartments. Maybe you should look for a house, and go with all the good advice you've had here concerning a backup system, and also buy yourself a little Honda or Onan generator. Don't worry about the Spanish, as all this is possible if you try hard enough.

raferguson

Nov 25, 2004, 11:02 AM

Post #14 of 14 (721 views)

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Re: [kirkswig] Building my own uninterruptible power supply (a really big one)

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Actually, a surge protector can be useful even without a ground. A ground is a good thing to have, but not necessary. When a major surge hits, the ground will not really be at ground potential anyway. Ground is not always the ideal perfect ground that everyone tends to assume. This incorrect understanding of ground prevents people from understanding complex systems, especially when radio frequencies, wiring failures, lightning, and surges are involved.

My earlier post mentioned differential voltages. If the various inputs are tied together and protected by a surge protector, then all the inputs will tend to move up and down together. This prevents smoking the equipment, since the surge goes through the surge protector instead of the modem, etc. Imagine, for example, if the surge comes in on the hot line, but not the neutral. A surge protector will tend to bleed most of the surge from hot into neutral, and prevent the surge blowing the power supply. Ground is not required.

As far as the phone system is concerned, I suspect that it will not be easy to make sure that the batteries completely float relative to the 110VAC power and ground. It depends on the design of the charger. Chargers do not necessarily isolate the input and output, especially in surge conditions. Obviously if you unplug the charger you are safe, but most systems leave the charger on all the time.

Richard

http://www.fergusonsculpture.com