Beefy Battery Backup Still Running After A Decade

In 1997 [Michael Butkus Jr.] found an uninterruptible power supply in the dumpster. The batteries were shot, but he needed a backup to keep his pellet stove running for heat, drive the exhaust fan to keep the smoke out of the house, and power his computer and other electronics. After a bit of head scratching he decided to beef up the UPS using deep-cycle batteries.

He actually built two of these. One is smaller, and similar to what we’ve seen before. The other is larger and uses four batteries, two pairs in parallel which are then connected in series. He’s careful to use heavy gauge wiring and 50 amp fuses for each battery, both of which will protect against the risk of fire. One thing we found interesting is that the batteries are stored in the basement, directly below the UPS which is connected via a short run of 12 gauge home electrical wire.

We were happy to see that he’s done updates at the top of his post over the years. He lost a few batteries due to neglectfully letting the water levels drop too much. He did switch over to sealed automotive batteries sometime in 2004 or 2005. Looks like things have been going strong ever since.

[Thanks Spencer]

39 thoughts on “Beefy Battery Backup Still Running After A Decade

  1. The batteries are the only things that have to fail in these.

    Prior to 1992 or 1993, the batteries were US made, and many of them lasted almost seven or eight years (if lightly loaded) before bulging and suffering the various forms of battery death. Unbelievable. I know of one unit that lived for almost 10 years.

    Just after that, battery manufacturing moved to china, and the lifespan dropped to 3 years or less. Then, as if chinese made electrolyte wasn’t cheap enough, they moved battery manufacture to india. Lifespans dropped to 12-15 months, and I wouldn’t be surprised to learn that the electrolyte was produced via bilogical methods. Absolute trash.

    The units are being produced in Thailand and China again, and have started getting better again.

    But seriously, I have UPS units that were built in the early 1980’s that are still running with periodic battery changes. They’re inefficient, have mediocre capacity and take up too much room, but they’ve been running in an outbuilding in the northeast for almost 2 decades.

  2. If the author of the web page is reading this, please
    (1) make your background colors less painful on the eyes,

    (2) correct the factual errors in your power calculations (a 700W UPS can deliver 700W to a device at any given instant, it’s a measure of force. This has nothing to do with a 10-minute capacity, the unit for that is watt-hours and measures work.)

  3. I’d recommend sealed deep-cycle marine or computer backup batteries. Automotive batteries are usually shallow-cycle, which is pretty much completely wrong for use with a UPS.

  4. I would not exactly trust 12 gauge wiring with 50 amps..

    That is a pretty solid chart to go by. Even for solid core wiring, he should be using at least 6 gauge for safety reasons.

    If it is only like… 6 feet, then 8awg would be fine.

    But thats just me. Household wiring @ 12 awg is only rated to 20 amps.

    Aamperage is amperage. 20 amps at 120, and 20 amps at 12v have very little difference in terms of heat generated by the wire.

    But 50 amps @ 12v is a TON more current than 20 amps at 120. Even if the wattage is vastly different.

    There is a reason you need much larger wire in 12 volt systems than you do in your walls.

  5. @james…

    a 15 amp fuse on a 12 volt line would blow when the draw exceeds 180 watts. Likely the actual voltage will be slightly more than 12, which gives you some headroom but.. even assuming 13v that would not be nearly enough of a fuse. That would be unacceptable.

    Which leads me back to my previous post.

  6. The point is in case of overload, you WANT the FUSE to MELT, not the wire. Thus, bigger wire should be used. On my 12v stuff, I preffer going even bigger when practical to save resistive voltage drop. AT 120AC, a 1V drop in the wiring is hardly going to be noticed, however when it is at 12V. (Remember ohms law, V=IR, for the same power [watts], same wire [ohms] your current is lower, thus less voltage drop. This is why the high tension lines run in the thousands of volts – less “wasted” power heating the lines.

  7. Nice hack, well documented. Had a discussion about this technique recently on another forum. Few people realize the potential for switching to better batteries in a UPS, so it’s good to see this getting some more attention.

    Sealed auto batteries only work if you’re very careful to limit the depth of discharge. Even one deep discharge can destroy them, or reduce their capacity severely. Regardless, they can be used successfully for a long time with some caution if you require relatively short run times.

    Deep cycle marine batteries are a much better option. As for the watering issue the author reports, the reason auto batteries are sealed and maintenance free is because they have a catalytic converter inside that converts the oxygen/hydrogen gas released from charging back into water.

    You can get retrofit caps for deep cycle marine batteries which include the same converter, and can greatly reduce maintenance. They work best with moderate recharge rates; fast charges will overwhelm the converter and cause gas release (which occurs even in a “sealed” auto battery). An example product is the “Water Miser” Battery Cap.

    Another alternative may be a battery auto-watering system. I haven’t used these and don’t have a reference handy, but I do recall seeing one some time ago.

  8. @onlinepharmacy

    Sadly, the answer appears to be yes.

    It’s not like ADD is a new thing, is it? There are thousands of people like me. We’re useless to society for anything long-term, but we’re just bright enough to figure out how things work and make something happen. We’re Hackers.

    I may have worked in a bunch of fields over four decades, and I may have learned a ton of science, math, psychology and the classical arts along the way, but I still think of myself as an uneducated hillbilly hick mechanic who is generally lonely except in a room full of drunken scientists and mathematicians.

    All I think about is the stuff I haven’t done yet.

    I’m at least halfway to expiration, and I have yet to sleep with Paris Hilton, or visit Afghanistan, or figure out how to get myself above FL850 before I die. But I’ll keep trying.

    What are you doing with your life?

  9. If you want a really, really long lived battery and don’t mind the absolute penalty for going off the reservation when it comes to efficiency, you can construct nickle-iron batteries. Nobody makes them here, as far as I know, but they’ll be back. They were all the rage a century ago.

    They don’t work that well in the cold (ability to supply current drops off as temps drop off), they charge like snails on sandpaper [actually a good thing], and they suck at supplying high currents. Finally, they also don’t hold a charge for that long… Let them sit for a few days, and you’ll wonder where the voltage went.

    Now for the cool part – they will take abuse like nobody’s business. You can treat them like an inner-city 8th grade teacher, and they’ll just keep working until someone puts a bullet through the glass.

    Seriously – these things have staying power. I’ve seen nickle-iron batteries more than 40 years old (I think, anyway) that still produced measurable voltage, although they were disconnected from discharge circuits.

    So in summary: Nickle-Iron batteries are
    Rugged, low/no maintenance (decades), have tepid output currents compared to size, can be ovecharged and run down repeatedly but will recover with time.

    The only limit I can think of is that you have to monitor the charging current if you want the best efficiency/lowest charge times. Otherwise, you can just boil them with charging current and live with the consequences.

  10. I asked APC about doing this once as I have a couple of their older 3000VA units. They said larger batteries could easily overload the charging circuit, so it was only practical with extended-run units which are designed to have external battery packs connected. Instead of connecting up 10 battery packs a couple of big deep-cycle batteries would appear the same to the UPS. Unfortunately at $700 for four batteries this is still on my to do list :-)

    Also on the page it says never to turn a UPS off when the power is out because it won’t turn on again, to protect you from plugging it into a bad outlet – however most if not all APC units can be “cold started” in this situation by holding down the power-on button for a few seconds so this isn’t a problem for those. (This is also how you discharge the capacitors once you have disconnected the batteries, otherwise it can still deliver a welding-level burst of current even weeks after the batteries have been removed.)

  11. The neighbors up the street were throwing out a nice little ADC 600 unit because “the new battery is, like, $100”. Of course I took it home – new battery (tabbed, sealed lead-acid) was $19 shipped from Allied and it’s still working 4 years later and protecting me from Illinois Power’s usual 7am four-second outages.

  12. One long power outage all I had was a deep cell, 1000 watt inverter and standard automatic automotive deep cell charger.I used them to run a small freezer about 120 watt average load.If your running computers you may still need a power conditioner(Apc). I also don’t know how many deep cells you can add safely.

  13. Wow, after visiting that site and uncoiling my small intestine… pretty cool idea that most are a little scared to do, sparks and all. But my brain is now a pool of lymph nodes from that webpage design.

  14. @Spencer: Check the APC website, the wiring fault light means something else but I forget what. It is recommended not to plug your UPS into a surge protector but I’ve never heard of a practical reason why, other than it might switch over to the battery for a few seconds when it otherwise wouldn’t have to.

    1. You shouldn’t plug the UPS into a surge protector because if the surge protector is a “good one”, they have a filtering system based on induction, and this would mess with the protection and power filtering system of the UPS.

  15. I’m from India. My UPS is made in India. My batteries are also made in India. My UPS is 12+ years old, and the last battery (tubular) lasted 8+ years. Current one going strong. Moral of story, there are good (international std) batteries and bad (backyard std) ones. Choose wisely and you will have a story to tell.

  16. Did a similar hack, used 4 gauge wire wire and a 200A circuit breaker. Although my inverter is 1800W(err supposedly). The main thing is my runs of 12V wire are less than 8″ long. The extra batteries and UPS are mounted in a cabinet. I don’t like the idea of wires like that being left on the floor. IMO the batteries should be as close to the inverter as possible, less voltage drop too :)

  17. I changed the color ! I did this back in 1997 ? Your 14″ screens did not scream color.
    Both sets of batteries are about 6-7 years old. The lights flicker here in Jersey and just last week were out for a minute. TV and computer just buzzed along fine. The sealed car battery don’t require watering that much.
    Your UPS is a surge protector, I tell pellet stove owners that all the time.

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