UPS with dead batteries reborn as a whole-house power backup

[Woodporterhouse] must deal with regular power black outs in his area. He recently converted a rack-mount uninterruptible power supply to feed a portion of his mains wiring. This one is not to be missed, since he did such a great job on the project, and  an equally remarkable job of documenting it. It’s one of the best examples we’ve seen of how to use Imgur as a project log.

The UPS still needs to have a case, but it doesn’t need room for batteries as he’s going to use a series of high-end sealed lead-acid batteries. So he cut down the enclosure to about half of the original size. That’s it mounted just above the new batteries. For this to work you need some type of transfer switch which can automatically patch between incoming line voltage, and the battery backup. He already had one of these switches in place for use with a generator, that’s it in the upper left. The entire system powers a sub-panel responsible for his essential circuits — the electronics in the home and a few lighting circuits (we’d assume this includes utilities like the refrigerator).

One really great feature that the reused UPS brings to the project is a monitoring card with a NIC. This way he can check the server to see if the UPS is being used, and how much of the 14 battery life remains.

[Thanks Ross via Reddit]

Comments

  1. BadHaddy says:

    My only beef with this is the UPS will charge the batteries rather slowly, as their AH capacity is MUCH higher than the original batteries. You might be able to adjust the charge rate in software or tweak the unit itself.

    If you dont feel QUITE as brave, and have around 300 spare dollars, you can get 99% of this in a quality, safe, and warranted unit. Look at triplite’s Inverter/Charger units. I dropped about 1800 on my unit, and its capable of 12,000 watts for nearly 5 minutes straight, and capable for 9000 watts for hours. Totally worth it if you wanna go big.

    Nice hack none the less!

    • Woodporterhouse says:

      They do charge slowly thats for sure. This style UPS is most likely set for a “slow & low” charge for the 8 pack of 7Ah batteries that come standard.

      They’re made for quick blips(1 second to 5 minutes), and all computers attached to it are supposed to have the client software installed to take care of an orderly shutdown if the loss of utility is longer then spec.

      But yes, if someone has a few bucks and wants to invest in a charger/inverter, definitely a good idea. This is my 2nd setup, because the first one crapped out after about a year and a half. UPS capacitors like to dry out and either explode or catch on fire…the fire suppression is a different project though. :)

  2. Dan B says:

    I would assume that it wouldn’t include the refrigerator unless you aren’t worried about letting the magic smoke out. Motors are a terrible draw on inverters. Right at the startup time.

    • Woodporterhouse says:

      Nah no fridge…just the electronics in the house, and some lighting in case the Zombies, Soviets, Terrorists, or whatever the fear of the day is and the power goes out.

      The generator subpanel is for the fridge, well pump, furnace and giant spotlights and speakers to annoy my neighbors when they have no power.

  3. Alexander says:

    Awesome! I cant wait to have some extra time to give this a shot (and a qualified electrician) :)

    • Woodporterhouse says:

      No electrician necessary, but it does help…

      Just adhere to code, otherwise your homeowner’s insurance won’t cover you if the place burns down.

      The fault in the FrankenUPS project is with the batteries. Teh plywood is fire code, but they are not in an enclosure which is required by code.

      Its on my immediate list of upgrades for this project.

  4. GZ says:

    I’ve been thinking about this exact same project forever, just never took the time to get it started.

    Now I’ve got some great inspiration!

  5. fdawg4l says:

    How is the UPS software determining the battery run time? Was the software recalibrated using the new high density batteries, or is it falsely reporting the original numbers?

    • BadHaddy says:

      The APC SMARTMON card is universal amongst APC’s larger devices, and can be tweaked by typing in battery capacity.

    • Woodporterhouse says:

      Excellent question. The APC mon card I believe, has preset battery life presets for the model it is connected to, and when you enter the number of battery packs, it calculates the runtime, using the current wattage load.

      Being that I used non-APC spec’d batteries, the time is obviously off. I had no problem posting the picture of the 14 hour runtime though, because the longest outage I’ve had here running purely off of this setup, was about 11 hours.

      I still have to do some calculations and such, but I would say the runtime meter is +/- 30%

      Still not bad though…

      • malvineous says:

        If you’re using one of APC’s monitoring cards you can load the UPS above 30% and perform a calibration through the monitoring card. This runs the load off the battery until it goes flat (when it switches back to the mains) and uses the run time to recalculate the battery capacity. APC recommend this is done regularly as the batteries age and lose capacity so that the predicted run time is kept accurate. I found it much more reliable than faking the number of battery packs connected.

  6. zigzagjoe says:

    This should be able to deal with a fridge and some other devices. Still not the best idea to run a fridge on it, but it should be able to handle it.

    Runtime seems to be in the right region for the new batteries, seeing as the APC chart for this model says two hours and a half at 250 watts with the built in batteries.

    http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=SU3000RMJ3UOS3&total_watts=50

    • Woodporterhouse says:

      It would probably run the fridge without issue, but I haven’t tried.

      Motors and other “big draw” items aren’t a good thing to run off of UPS unless its critical life safety, or some other exception. They’ll kill the batteries quick, and cause wonkiness if they are 3-phase for sure. Don’t have to worry about 3-phase though at the house… :)

  7. No One says:

    This and questions of whether the fridge will blow it makes me wonder what the difference is, internally, between a high-end, high-wattage UPS and the storage/inverter setups usually seen with solar installations.

    Do the solar installation inverters merely have beefier sub-components or do they use a completely different circuit?

    • BadHaddy says:

      Large inverters (like the Outback solar inverter) usually bank together multiple inverter circuits and sync their output waveforms. They have additional capacitors and coils to help handle motor surges.

    • NewCommentor1283 says:

      as far as ive seen/heard/read, 90% of all “ups/sps inverter”s are not TRUE sinusodial(sinewave) output and thus the unit’s internals are MUCH simpler and CHEAPER.

      fridges, and to a lesser extent all 60hz ac motors HATE “modified sinwave” outputs and often either stall(veryvery bad) or blow the crap out of your mosfets… (or just get warmer and have less torque). im talking about the mosfets that turn your “inverted” 180vDC into an average of 120vAC@60hz-mod.sinwave

      the fridge as well as other specific applications of motors have existing extra stress / torque requirment during startup. fridge has load of frefrig. gas/liquid backed up ready for pumping. if it stalls from lack of tourque bcuz the mod.sinwave, then it will start to draw WAY much more current, destroying things. (motor-brushes, inverterparts, ect)

      PS: on a fridge, I THINK the overheat sensor is inside the sealed chamber, which is okay, but on other equipment, check to make SURE the sensor is NOT bypassed before trying this! … or use an extra temporary fuse.

      PPS: this equipment is designed for computer backup, and thus a computer backup ups/sps will almost never have the more expensive (and less eficient) true sinewave inverters.

      PPPS: ive heard of very bad things happening when you go to charge a nicad-built in pawerfailure rechageable flashlight/nightlight from squarewaves, modsinewave is a cross between square and sine waves. most user manuals that i have read say “WARNING: DO NOT USE THIS PRODUCT TO CHARGE NI-CAD BATTERIES AS THEY MAY OVERCHARGE AND CAUSE BATTERY TO LEAK OR CATCH FIRE.”
      i assume they are talking about slow-dumb-simple chargers, and not the computerized ones.

    • wernicke says:

      I don’t know anything about solar inverters, but industrial VFDs that run motors at the end of very long cable runs can use sine wave filters (google it) to achieve very nice looking sine waveforms from choppy inverter outputs.

      • NewCommentor1283 says:

        i think

        BadHaddy
        wernicke
        and me

        are all correct. im sure you could use extra coils and capacitors ect to run a tempermental motor on squarewave ect

        just wouldnt fit inside your SPS/UPS with limited space. (and DEFINATELY not inside your “travel” inverter XD )

        i havent seen the circuits you two describe in person, but im pretty sure it would be a unit itself, and as big as or bigger then the inverter itself. (without battery box of course)

        which does not lend itself to “portable” or “compact” or “visualy appealing” or “cheap” or “lightweight” or “i use a mac and my sister would kill me if it wasnt white with silver trim…” == all things i dont care for.

        PS: i know they sell 12vDC fridge compressors, and i know they sell 120vAC60hs fridge compressors,,,

        but do they sell 180vDC fridge compressor-motors????

  8. aztraph says:

    That Is so cool, Much better than mine http://www.myspace.com/480608276/photos/16863995#{%22ImageId%22%3A16863995}

  9. malvineous says:

    For anyone who’s interested I contacted APC about this sort of thing some time back (wanting to add a battery bank to a UPS) and their response was that the charger circuits in their UPSes are only designed to handle the internal battery capacity. They said that the more batteries you add, the more current they will draw when charging and it was likely that adding too many could overload the charging circuit.

    They did say that their extended run models (those with XL in the model name) are designed to have up to 10 external APC battery packs connected so the chargers in those are able to deliver much higher current. Their suggestion was to get an XL model and add batteries up to the capacity of the 10 external packs + the internal batteries, and then there would be no risk of overloading the charger.

    • Woodporterhouse says:

      Indeed. I went through alot of specs for the non-XL models, and the one thing that I found, is that they are very similar to the XL’s.

      The model that I used, had everything set up for an external battery pack(APC connector), and I’ve had this setup for about 3 years total now(version 2 in the pics after the caps dried out on version 1).

      Obviously I had my concerns, but it has been working without issue.

      The way I’m figuring is that the charge circuit is limited no matter the type/quantity of batteries. XL or not. If a battery bank is completely depleted, the charge circuit in the UPS only knows, “time to charge”, and is internally limited as not to burn itself out.

      If there is a 1 battery, or 20 battery bank connected to it, it still only knows, “time to charge”, and is regulated.

      I haven’t researched this enough though to give a solid answer. All I know is it’s been flawless for a while, except for when the caps dried out on my last setup, but this is a known issue with all UPS’s.

  10. echodelta says:

    Any well stocked and insulated fridge is good for a day or more. If the power is off longer there is a change in living. Keep jugs of water in the bottom and frozen ones in the freezer. It will cycle less often, than if low on stuff (beer).

  11. 556NATO says:

    I bought a Xantrex 3000W full sine wave unit that can handle like 6k for motor starts… I am running it from about a dozen gel cells and it works great. The inverter cost $450 on craigslist and the batteries were purchased at a local auction for under $250. The setup works great and keeps my entire entertainment center + lab going during the regular blackouts we have here. If the power stays out for more than 30 minutes, my generator starts up (or it starts up when I hit a button). It’s a pretty slick setup and has saved me numerous times.

  12. Woodporterhouse says:

    One thing that wasn’t noted, my friend Marc got me the UPS from his friend.

    Thanks Marc!

  13. QBall says:

    Be forewarned… you WILL be amazed at the amount current required to keep the batteries topped off as they get older (mere months). I had pretty much the same setup with two 3000VA APC UPSs and it was amazing. When the power went out, we barely knew it. UPS took over the demand during an outage and then the generator automatically kicked on to cover the load within 3 mins. It was beautiful. Then about 5 months passed by and the electric bill began to grow.
    We aren’t talking $20 over, we were in the $100+ range (over the regular) every month. Removed the UPS and the bills dropped dramatically. A friend of mine had the same plan and built it. He realized the same increased bill after approximately the same time period.
    Just food for though…

    • Davek says:

      An additional $100 a month is something like 1400W, somewhere around 100 amps of charge current (assuming the UPS itself didn’t need much power).

      What size of battery bank were you running that would accept 100 amps of standby charge?

  14. mike bradley says:

    i dont understand the transfer switch. power is supposed to flow throuh the ups full time and the ups powers the outlets full time. if you use a generator, then use transfer switch so its seamless from mains to generator. ups covers the switchover time and delayed start

    • malvineous says:

      I think the transfer switch here is functioning as a UPS bypass switch, so you can remove the UPS from the circuit if you need to do work on it, without having to power down the load.

    • Simon says:

      Under normal circumstances, a UPS won’t be backfeeding into the mains supply. It will only be powering the equipment connected to it. In this setup, there is the issue of conflicting waveforms from the inverter and the grid, which is why you don’t want both feeding into each other. The UPS won’t like it, and the grid won’t like it.

  15. Drone says:

    I agree with many here. This is the wrong type of UPS for this application and adding more batteries like this is asking for even more trouble. It may “work”, but for how long and how well? Make sure your smoke alarm is working – and test it often.

  16. Cyberteque says:

    I really need something like this!
    It takes a “slow count of 3″ before this baby kicks in…

    By that time my server, network switch, XP and Linux box have all shut down!

  17. mam5561 says:

    well basic ups theory says that you don’t need an Ats, the ups always syncs to the bypass source, and produces the same well basic ups theory says that you don’t need an Ats, the ups always syncs to the bypass waveform. This looks like a basic computer ups. i work on large scale UPS’s 300kva to 1000kva per module for a well known manufacturer. As far as the post for 9000 watts for hours… any ups rated battery is only specked for a discharge of 15 mins. while it may run for hours, no ups was designed to supply mains voltages for longer that 15 mins. Long enough to crank the gens and get them stabilized. The inherent fault of a ups system is that you are demanding a huge amount of current from a battery string that is in series (540 vdc for 480 vac and typically 330 vdc for 208 ac) one battery fails everything fails. And mosfets ??? no they typically use large SCR’s for the rectifier, and IGBT’s for the inverter.

  18. Lummox says:

    I’m running a 3KW APC rack mount UPS that’s several years old. I gutted the dead battery packs and wired in 4, 95 amp hour sealed 12V batteries (with breakers) to make a 48V pack. They were surplus, proper sealed UPS batteries from a radio station up a mountain. The UPS has a decent cooling fan and seems to charge up that massive pack without stressing anything or overheating anything.

    This runs every piece of fussy electronics in the house. Multiple TV’s, stereos, computers, etc.

    I live in an area with industry and get terrible power spikes, surges, outages, brownouts and just general noise. I finally associated all my desktop computer glitches with big welding projects on my Lincoln squarewave 185 tig welder as well. Since I did this mod, I have zero computer issues and a much quieter stereo to computer sound connection.

  19. lejupp says:

    High power electronics screwed to a board of plywood….isn’t that a fire hazard?

  20. Marvin says:

    Is this wire kludge US standard wiring practice? Comparing this to german installations is like comparing a pig sty to a cleanroom…

  21. fartface says:

    He may have battery life and charging issues down the road. You need to have the right charger for the battery type, and UPS chargers are usually horrible at best.

    This is a very good gorilla install, but if the work had permits pulled and was done legally it would never pass inspection.

    If someone really wants to do this the legal way, there are a lit of inverters that are low cost (under $500) and a good charger will cost about $125 that will make your lead acid batteries last at least 5 years.

  22. This Guy says:

    Wow those panels are filthy…

  23. noah says:

    i have the same UPS and wanted to do the samething. (but up to code) so i got this APC switch. it will take a ups input and gen input. http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=UTS6 and it will even start my gen.

  24. Ben says:

    I did something similar. I got a 2000 watt 48V UPS from a friend who recycles computers. My home-built electric motorcycle is also 48V.

    I set up the UPS with an Anderson quick-connector with a matching one on the motorcycle. That way, I can use the UPS as a charger for the cycle, and run my house from the motorcycle in a blackout!

    The UPS is rackmounted in an old rack in my garage, but after seeing this one, maybe I’ll wall-mount it!

  25. will1384 says:

    I have four XPower PowerSource 400 UPSs,
    two of them have 12v automotive deep cycle
    batteries attached, I got the UPSs to keep
    my keep my computers and TVs safe from my
    old Colman generator, from lighting, and other
    power problems, with a single regular automotive
    deep cycle battery used in place of the XPower
    PowerSource 400’s normal battery I can run my
    computer and its monitor for hours, most of the
    time longer than the power outage, it does
    recharge the larger battery slowly but it only
    seems to take a few hours to recharge it, I have
    used them like this for years, works well.

  26. Necromant says:

    IMGUR is dead, HaD-effect?

  27. vijay says:

    hi
    my ups is not charging the batteries
    can i fix it
    or can u help me fix it?

  28. Mr. Boozer says:

    Add more cooling, the original design was for less run time, and the UPS was kept in a air conditioned space. Heat is the great destroyer. Put two temperature controlled muffin fans on the bottom, and let them blow upward. Anything that you can do to cool the UPS down, will extend its life. The original fans were designed for a specific run time, and draw. It looks like you have it installed in a garage with no air conditioning. So while it is a great design, and it works, we are only talking about extending its life. Joe

  29. abdullahi suleiman says:

    this circuit did not work for me please what should i do

    physics with electronis student

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Follow

Get every new post delivered to your Inbox.

Join 92,170 other followers