Modifying broken UPS for long endurance BACKUP POWER! 

*Hydrogen? Explosion risk? Why not lithium? Parts list?* !! FAQ HERE !! Stream discussing some of these: ru-vid.com9JOuYWRu3h4?feature=share *What about Hydrogen?!* A single battery at float charge has very slow rate of offgassing. If the battery released enough gas to be an issue, it would be dry in weeks, as would every other battery ever connected to a battery maintainer (which defeats the purpose entirely). This is one battery in a 1960s building with significant air exchange, not a bank of batteries under heavy cycling in a hermetically sealed bunker. Yes an AGM would be safer, and is a possible future retrofit. *Modified sine wave will destroy your computer!* My computer's PSU is rated for use on modified sine, according to the manufacturer on the official FAQ. Not all brands or models give that assurance. *The battery will spray acid if it suffers a major failure!* Even a sealed or AGM battery will vent under those conditions, though random catastrophic failures are very rare without external causes such as mechanical damage, short circuit, or extreme overcharging. *What about LiFePo4 / Lithium?* Higher performance but expensive and needs separate battery management; planned for a future version 2 of this project! *Y'know, there's a thing called a deburring tool instead of a utility knife...* I had one. Discovered it was missing when I went to do that stage of the project and realized just how many holes I had to drill. I have since replaced it. And gotten a step drill bit as well. *The fan is blocked! There's no airflow!* Fan has more clearance than first appears. Compare position of fan intake and the velcro at 27:46 and position of velcro and the channel in the battery box lid in the side view at 30:15. Almost as if I planned the placement! Not as effective as open air, but still plenty. *Just buy a huge power bank with built in inverter!* Power banks with UPS functions are neat, but every one I've seen linked so far has abysmally slow transfer time of 30ms, which would guarantee my computer shutting down during the switch. Also, units with comparable runtimes get very pricey, approaching 4x the cost of this project. If you have suggestions, please let me know. At a future point with more budget, I'd consider doing product reviews. *How long does it take to charge?* It will get there. Eventually. The charger in the UPS is a maintainer more than anything for a battery of this size. Significant discharge will require a boost with external charger. Adding a better charger is another potential future upgrade. *Why didn't you start with a top of the line high power UPS?* I found this one for free in a scrap pile in the stairwell of an office building. I was either going to analyze why it failed or replace the internal battery. Then got annoyed enough at a power outage to try strapping a car battery to it and seeing what it could do. Results were better than expected, so I turned it into a full project. Of course it's not perfect, but it does do what I asked it to do, and I got a cool video. *Why keep the alarm buzzer?* I wanted the option to have the alarm. But also an option to turn it down. A latching, auto reset mute circuit would have been a cool alternative where could just press a button to silence the alarm and it would stay off until the next power loss event. *Ew the music!* Agreed; I could have done better and I'm working to improve future content. If it bothers you that much, nobody is forcing you to watch :) *Parts list??* Here you go! Read datasheets and verify before ordering. I take no responsibility for any property damage, injury, etc. arising from attempts to replicate this project. P1 | PTN16-D01115K1B1 | 1k Potentiometer 0.125W Any similar part will work D1 | 1N456ATR | General Purpose Diode 30V 0.5A Any similar part will work Qi | 2N4403TAR | General purpose PNP transistor 40V 0.6A hFE 100 Any similar part will work Qm | IRLZ44NPBF | N-Channel MOSFET 55V 47A Threshold 2V Overkill for this application; any similar part will work C1 | EEU-EB1E101SH | Aluminum Electrolytic Capacitor 100uF 25V Any equivalent part will work R1, R3 | CF14JT1K00 | 1k ohm 0.25W Any equivalent part will work R2 | CF14JT560K | 560k ohm 0.25W Any equivalent part will work

I liked how for every modification step you checked that it would not catch fire.

Always check the contacts on these older UPS units, over the course of years they can start to subtly corrode then heat-up and corrode even further. I had one getting to the point I heard faint arcing, the problem connector was immediately obvious, discolored and pitted metal on the contacts(on the high-current LV side of the transformer interconnect), The wire guage was too big to fit the holes present, so used forked spade terminals to repair it and cut off one side of each spade to use as through-hole, soldered those in, checked thermal camera, and have been good ever since. This is one of the first UPS units I ever bought 15+ years ago and it's still going strong. Each time I've tried to replace it, it keeps outlasting it's replacements.. one lost it's mind and exploded it's push-pull FETs randomly one night, the other started kicking the GFCI at when it performed it's sporadic self tests, never a dull moment.

8 years ago, I lost the power drop and breaker panel from my small mountain house during a landslide. (As well as many other things!) It took a year and a half to get everything back on the grid. In the meanwhile, I took the 650 model of that UPS, bought 6 golf cart batteries, brought out some heavy leads from the UPS, tied the batteries up with an external 60A charger and ran all the house lighting (LED) cable modem, router, pico cell site and 32" TV/monitor and laptop from it for about 16 months. Charging during the day with a small inverter generator. Worked well for all that time, never an issue. After I was back on the grid, pulled the UPS apart. No signs of heat or component stress whatsoever, still worked great. Maybe pulled 20-30W at night, max maybe 200 during the evening. Carried me well for those several months. Now I've got 20Kwh LFeP04 battery and a 3000W inverter/ups/charger which can handle everything for a few days. (mtn folks lose power a _lot_) But that little APC did great! The transformer based ones are very solid.. Good vid!

I modded the same exact UPS with a car battery to power my WiFi router, cable modem and cable amplifier mounted outside so I can keep my internet running and entertain the family when the power goes out next time. Good video

Great project. I did this exact same thing a few years back (minus the fan driver circuit). I ran into a problem that you will probably run into as well. The batteries in these UPS devices are AGM (absorbed glass mat) but the boat/car batteries are FLA (flooded lead acid). I had a problem where the float charger in the UPS would basically boil the FLA batteries dry and destroy them. I found out that the charger was trying to overcharge the FLA batteries. The "full" voltage that the float charger in the UPS I had was 14.5 volts due to it using the AGM battery. This is too high for a FLA batteries. They should float about 13.5 volts. I could not find any way to adjust the float voltage in the charge circuity so I gave up on the project, I just went through too many batteries to make it worth it. Another thing I found was that the FLA batteries off-gas quite a bit while they are charging. At first I had the entire setup inside the house, but things in that room started rusting and the I started getting complaints about the smell (the off-gas is also explosive. It's hydrogen gas) so I moved the batteries outside and ran the charge wires through the wall through and existing hole. You might look on your APC board and see if the float voltage is adjustable. Just my opinion and my experiences.

I recommend you pick up a pen-style deburring tool. Cheap and works much better than a file or utility knife for holes. Great video.

Great upgrade of old hardware! I really appreciate how thorough you are at every step.

Got a pile of UPSs here for recycling, all had bad batteries when I got 'em. I'm going to have to look into seeing what can be done with them... :-)

Conical hole chamfering bits are your friend for cleaning up holes. Muuuuuuch easier than using utility knives.

A most honestly an 'Engineered' solution to this problem. Step by step what I would do myself, but also being honest, a much more presentable "product" that I would have likely done myself, if for my own use. Currently have a slightly smaller APC that I'm going to perform a similar upgrade to. Thanks for the work!

The biggest issue I saw with is was you went through all the trouble to install a cooling fan and then restricted the fans ability to take air in by not adding space. Yes, I notice the channel in the cover. But once the blades stall, you basically loose all of your static pressure. You can hear how much more noisy the fan is now that it is on the cover of the battery case. This is indicative of the fan stalling

Way cool and most definitely a viable solution for longer than 12-20 min battery backup! Keep em coming!!!!

If all you need to power from UPS is computers (either full size or laptops), then there is an option which bypasses all the complicated electronics in a typical UPS: All computer power supplies, laptop charging bricks and flat-panel monitor power supply boards today use lightweight switched-mode power supply circuits to convert mains AC to the low voltage DC the computers actually run on. In all SMPS circuits, the first component the incoming mains AC is routed to after the input socket and switch is a bridge rectifier, which converts the mains AC into DC at more or less the same voltage. Also, pretty much every SMPS circuit built within the last 15 years or so can run from a fairly wide voltage range, usually anywhere between 100 and 250 volts - this is so the manufacturers can use the same circuit for every country which has mains AC power. So it doesn't matter whether you give the SMPS pure sine wave, modified sine wave or even square wave. The AC frequency makes no difference either - it can use European 50 Hz, American 60 Hz, or even in theory the 400 Hz used on airliners. You can see where this is going of course: Since the mains power goes directly into a bridge rectifier first, it also makes no difference to the SMPS whether it gets AC or DC, as long as the voltage is within that 100 to 250 volts range. So if you can get a load of cheap old car batteries from a breakers yard, all you should need to do is wire 10 of them in series and connect the resulting DC voltage to the computer power supply - which would be somewhere between 110 and 145 volts depending on the state of charge of the batteries. Then just have some kind of automatic change-over relay to make the battery bank kick in the moment mains power is lost. This should be entirely feasible - after all, landline telephone exchanges have a similar battery backup system (albeit at 48 volts) which is how your landline phones and landline-based internet service providers still work during power cuts. The same system would also work for many other domestic appliances - LED lights use tiny little SMPS units built into their bases, so they can work from DC. Any resistive heater would also be fine, as would anything driven by universal motors - these have always been able to work from either AC or DC

I have thought about doing that for so long. Glad to see I'm not the only thing thinking in this line. Learned a few things from your video. Thanks!

A fully charged battery is a happy battery. At 13.8 volts, the UPS is providing float charge for a gel-cell battery. This will not satisfy the AGM. If you want long life (up to ten years), I would disconnect the battery from the UPS and connect an automatic (smart) charger with AGM charge parameter selection - about once a month. OR, at least after any significant discharge time. 13.8 volts will never fully charge the battery. nice project, thanks for the video!

Excellent video! Most was another language, but I stayed for the whole build.

Cool project! Gives me a couple of ideas for my own. Great work.

Best video connecting diy, solar/generator, off grid, sustainable power management . thank you.

you'd enjoy having a chamfer bit to tidy up the holes. safer, faster, and neater than the blade knife. :D thanks for sharing this build.

Have an Eaton true sine wave line interactive UPS, not a cheap unit. I added a T connector to the line between the internal batteries and the inverter. This connector is available to plug in an additional 24 volt 200 amp hour battery which uses the same type of battery’s as in the UPS but larger. My main concern is the algorithm used in inverters to determine how long they will run. I have no idea if they monitor load current as well as battery voltage to determine when to shut down. I use this UPS to feed power to a wood burning fireplace / boiler used for heating my home. It’s main purpose is to power a circulation pump to provide hot water to all of the radiators. If there is no power to the pump or fireplace, the control on the fireplace which has its own battery back up will shut off the air supply to the burn chamber snuffing out the fire slowly to prevent overheating the water jacket and blowing off all the water out of the safety. Currently the UPS will provide 110 minutes of run time utilizing a pair of 12volt 8amp batteries in series on a load of about 150 watts. Will try to figure out with 50 amps available how long it will run.

Very cool, man. Thank you for posting this. It reminds me to perhaps do better with what I was supposed to have learned in my BSEE degree (read: they taught it, I just didn't try hard enough and it's been years).

Nice work. Personally I'd have mounted the UPS on some riser blocks to give the fan a bit more space, but that said, it's still a very neat package. I used to be in IT, and we'd frequently remove and scrap large server UPS units. Companies tend to have service contracts in place that includes checking and servicing their UPS units, and these companies tend to see batteries as consumables, so the batteries in many of the unit's we scrapped were less than 12 months old. It felt like a waste to let perfectly usable batteries go for recycling, so I managed to persuade my boss to let me scrounge a fair few 6 to 12 month old NP12-12 batteries for free (My favourite price ! :D). I didn't really have a plan for these batteries, so I just daisy chained them all in parallel on a charger in the garage for about a year, but then one day I decided that if I didn't do anything with them it would have been pointless getting them, so I tested them all and matched up 16 batteries that were pretty much identical, then mounted then in groups of 8 in 2 heavy duty plastic toolboxes. I mounted a breaker switch, a voltage gauge and a pair of waterproof XT90 connectors on each box, then wired the batteries up in 4 groups of 2, all in parallel for 12V, and with each group having a fuse. The idea is if one in a pair of batteries goes bad and the other 6 try to rapidly equalise the voltage, it'll blow a fuse and then I only have a faulty battery (and one that's probably been damaged from over discharging) to deal with, rather than 8 damaged batteries. It also means that if a fuse blows it just becomes a 6 battery box until I replace the questionable pair, rather than a completely unusable box. This all get's me a total of 194Ah (2,304Wh) of capacity, but due to lead acid based batteries not being particularly happy about being run flat, I've set a much more battery life friendly 96Ah (1,152Wh) output limit for the pair. Because the batteries were free it turned this little project into a ridiculously cheap emergency power solution. These boxes now sit next to my desk, permanently connected to a 20A storage charger. Sitting on top of that is a 3rd identical toolbox which contains 2x 700w (1500w peak surge) 12v inverters, a 300w (600w surge) inverter, several XT90 to XT90 cables, various adapter cables to take XT90 's to things like XT60's, barrel jacks, battery clips, 12v car accessory plugs, and USB chargers, a couple of cheap inline "RC hobby" type volt meters that also log total amp usage, a plug in mains power meter........... And a horrendously power hungry 12v travel kettle (What? I'm not letting a power outage mean I can't drink coffee, am I !!!! :D). There's also a 12v soldering iron wired to an XT90, a selection of bare plugs, a couple meters of a few different gauges of wire, and a roll of solder, all in case I suddenly realise I need some adapter cable I hadn't thought of after the lights go out. :D I've already got a 1600w UPS on my main PC (I've upgraded the battery setup on that. It had 3x NP7-12's in series for 36v, so they came out and it now sits on a case extension that houses a 3P3S configuration of NP12-12's. While doing that I also noticed that mine had a couple of unpopulated spaces for 2 pin fan headers, so I soldered on some sockets that I salvaged from an old motherboard and, hey presto, they just worked. So...... Bonus !), this means the toolbox battery packs are really just to run anything else I want to use in a power outage. If power looks like it's going to be out for several hours I can drag these down to the kitchen to run the fridge and chest freezer for about a day, run the modem and wireless router pretty much indefinitely to get internet access back (Here in the UK, phone lines HAVE to be powered independently, so things have to be getting REALLY SERIOUS before the phones don't work, and according to a mate who works for the UK's main phone company, that includes any data that flows through those phone lines), or just run the modem, and a TV so I can sit back and watch Netflix for significantly more than a day while waiting for the lights to come back on. :D

Nicely thought out and executed

Be interested to see if you get much issue from the gases released from the battery inside the house. It's also explosive. Cars with batteries in the cab have vent pipes attached to the battery to push gas outside cab.

Nice build.

Interesting project. I'm pretty sure that your APC unit is PWM sine (crappy wave). I chose a small true sine wave (BSINE600 from Tripplite) inverter instead. The SLA batteries in these units are good for one or two shots at high load before they go bad, so i just left the original blade connectors for connecting the SLA battery and made an adapter to an XD90 connector. Then made an XD90 to lug connector adapter cable and hooked up one of the cheap 50AH LFP batteries (probably cheaper than your group 34 deep cycle lead acid battery) which only weighs about 9 pounds. The 13.5 VDC charging voltage from the Tripplite charges the LFP battery to about 96% of it's total capacity, which works great. I have been using this one for over 2 years now and it keeps the internet router up for almost a day, or my laptop and the router going for about 10 hours or so. Hopefully more people will be inspired by your video to "ditch the SLA" boat anchors that come with the vast majority UPS systems today and have a UPS that actually will run a higher load for several hours all while doing it yourself!

Loved this video, thank you so much.

I recently found that those oscillating saws work amazingly on these abs or other similar plastic cases. (If you need a straight cut)

Great, clean job. Love your attention to details. Properly done cabling and connectors goes a long way. My only (small) concern is small distance between box top cover and UPS leaving rather small space for air inflow for fan. Probably it's sufficient but I'd add some more distance, perhaps a piece of plastic, like a short pipe or a piece of cable tray or sth like this. Not sure it's needed, perhaps it's just my habits :) Anyway, great job!

Subscribed just because of this video. Took my apc added a second battery and volt meter. My type of diy. Great job

you reminded me of the old days, we did that 20 years ago to keep power in the house during the war but had 8 batteries connect it on it :D

Nice. I personally use an old APC SmartUPS 1500 to cover my router, wifi kit, TV, and a LED light in our living room. I use a large old car battery which is in a vented garden box just outside on our patio. We have lots of powercuts which is why i did this. Its enough to run the LED light and our internet kit for 4 hours. Plus the expensive TV is protected against spikes from the outages.

Love your HOT PINK GLUE GUN!!...LOL

I'm just getting into electronics and have had some UPS, so this was really cool to see.

This is so funny! I have this same exact UPS. I replaced the battery once about 5 years ago, and it recently died again. I bought a new large UPS. This would be a cool project for it!

You should discover the wonders of a "Christmas tree" (otherwise known as a step drill). Much of this project would have been much smoother with one.

i also did something like this. got a few ups that where throw out. i got a 60AH lithium battery with it's own bms. ran some wires out from the 600VA ups. works well for 12 hours for my nas. only catch is it take day plus to charge up again, which was expected as lead charges at 0.7A

I did this with a couple of them. I removed the battery and put in a PC fan and a small 120-12v PSU for it. I ran it off the inverter outlet rails. I broke out the wall between the battery compartment and electronics area. These are underrated to have passive cooling. With forced cooling they do so much more. I also partially bypassed the amp limiter.

Very nice repurposeIng of old UPS. Well thought out and implemented. I am now keeping my eyes open at rummage sales, 2nd hand stores, and Goodwill for a used UPS. I was concerning building one of the solar generators as seen on RU-vid. I want something to take camping or use in an emergency. But your project got me thinking about merging the two, something that I can use as a UPS at home and a solar system that is portable. The way I invision it, I wouldn't need an external charger circuit, or AC power inverter if I start off with the UPS circuits. The thing is, I'm NOT an engineer and don't know how to marry the two projects, and I don't want to do something that has electronic or fire risks. So I'm hoping you might help me by building a project that I can copy. ;-)

Nice to know something I did WAY WAY back in 2000 is being done today. People thought you would Burn your house down doing this. APC makes SOLID GEAR! In fact if you have a tired automotive AGM car Battery? I have used an old APC unit to "Charge it" (REfresh it) to bring it back to life from sulfation. If you ever want to test if a battery can really pass a load test on the cheap? Pick up one of these UPS units. I like the Cyber Powers as they have a display. But the APC units are built old school & SOLID. There is a 24 Volt unit that has a fan built in that needs to be replaced after a few years, but is a great unit to use with large and CHEAP standard automotive batteries. You don't even NEED Deep cycle batteries. You tend to barely use the deep cycling feature, so if it saves you money? Get the cheapest walmart battery you can get and enjoy.

Nice work and video.

Clean re-use of a UPS! I've always wanted a good computer UPS that allows an external 12v battery via plug, for my mini server farm.

Thanks for the vidja. Peaceful Skies.

Careful lead acid batteries emit hydrogen. Otherwise solid build. I have done something similar and recommend Bigbattery lithium 12v. They are more expensive but more reliable.

I did one similar a few months ago, I just rectified the drains of the main mosfets and that gave me 12V for the fan. Mine is non-isolated (FSP), so a solid battery box was required, but the low loss and ~70W load it feeds gives me excellent runtime on 50Ah. Enough fuses were added.

Very nice!

Cool. Will probably do something similar. Use a big rack ups next to my desk. I put a pwm fan controller to turn down the volume and keep it running all the time.

Nice! I had a bunch of batteries laying around already so I basically did the opposite, picked up a 1kW pure sine inverter and put that before the UPS. Eventually I'll probably make a failover system so it can switch automatically, since I don't have to worry about the switching time due to it being before the main UPS units. Maybe also hook it up to weather so it can precharge before a storm... yay scope creep A week before that however (because of course) I had multiple 24hr+ power outages, and ended up doing pretty much exactly this, but with a power supply powering the UPS off of said random batteries plus a pile of sketchy AF car inverters lol.

This is Great :) I have this same UPS running my Router and Internet box, ( its a old one I had from 10 years ago)

It videos like this that remind me why I wanted to study electrical engineering.

Nice job. I have a 20+yr old apc 2200 with an external connector for battery packs. Only downside is it runs from 48VDC & I'd have to drill a hole in the floor down to the garage to add more batteries.

Hey, thanks for the video. I now have a better understanding of what one is actually buying when one buys an inverter, and why they often *seem* so different from a UPS even though in principle they're doing the same kind of thing. It's all about the waste heat which sorta kinda varies proportionally to the amount of time the thing is on battery mode and the amount of wattage being pulled. I don't have the skill, patience, or tools to build one of these out of the similar UPS I have that also has a dead battery. But it's neat to see how it works.

lead acid outgassing does not only happen with higher charge rates and float voltages. give that wet battery a good discharge and then put your ear to it while it's charging and you'll hear it bubbling away. you did so good with the rest of the safety aspects of the project, should add a vent line to outdoors or switch to a big SLA.

I did a similar project for my network. I used an APC UPS from a Walmart Self-Checkout and it ended up having a pretty efficient switch mode power supply instead of the huge 50% - 70% efficiency transformer that most of these use.

I did something similar to this maybe 20 years ago with a HUGE old APC unit that ran 2 12v batteries in parallel. I used a pair of Marine batteries which are better suited to being discharged over a long period of time. It would run my 2000s PC, dual 19" CRT monitors, and network gear for at least a day. Honestly I never was able to run it long enough to run out of power. A bunch of internet "experts" informed me I was going to blow myself up because of the tiny amount of hydrogen released from the batteries during charging. I'm still here.

Very well done. Thank you for sharing your work; a device like this is attractive for keeping a photo printer running long enough to finish a job. A company called Noga makes excellent tools for deburring holes, if you're inclined.

you can also use a stepped bit as an impromptu deburring tool. Funny you'd post this. We have similar power issues where I live. I'm already using a 'failed battery' UPS for surge protection and I've contemplated this exact modification. Now I know what I should be checking before I do the work. Thanks!

Ah cool, you pretty much built a Tripp Lite APS though the APS had less smarts. Fun project, nice video.

i love that model and general design of UPS from APC. they use the SLA batteries that should be replaced about every 3 to 5 years depending on how bad your power system is (the utility). my goes down completely about 20 times a year and i have to replace the SLAs i use about every 3 years. the APC ones are by FAR the easiest to service. takes about 5 minutes. it actually takes way longer to source the replacement because you need to make sure its the right dimensions and tab size lol. pro tip, don't stockpile SLAs if you can avoid it. they have a shelf life and its the same shelf life of 3 to 5 years, even on a trickle charger

I’m watching your video on this ups, and get blown away when you bust out the field piece sman Hvac gauges. Now I gotta dig throuh your channel to see why you have EXPENSIVE HVAC tools on your workbench. I have several sets of them in my HVAC service vans.

Great reuse! There are a lot of these desktop SOHO UPSs' out there and they die all the time. It's important to note that not all car batteries would be safe for this use. This needs a sealed battery to prevent off gassing as that could create an explosion.

Our cable modem is in the garage. My backup solution for it is a little Eco Flow River 2 power station, clip clip the power cord for the cable modem and run 12V from the power station directly to the cable modem (since it takes 12VDC on its input). By leaving the AC inverter turned off the power station can run the cable modem for 3 days easy on its own during a power failure. Generally speaking, these UPS solutions are built into a lot of power stations these days so even for running AC devices it is pretty trivial, and you get a lot more backup time with a power station than you do with an APC UPS. -Matt

Great video.. 2 years ago I got given a apc750va unit for free from work ..I've added better heatsinking and a cooling fan and it runs from 3 car batteries recharged from 2x120w solar panels... Runs my workshop networking gear and pc for hours ... I've never managed to run the batteries out before the mains power has come back on ...but it's in excess of 3 hrs .... Also allows me to recharge laptops and power tools 'offgrid' I also have some 3kw 48v tripp-lite units waiting for when I can get some cheap car batteries...those things are built like tanks.

I did this back in the day with a "bad" 3000VA ups. It was 48v. Bought 4 AGM boat batteries. It could run 4 computers for several hours.

Oi. Your fingers sent a message: please stop lining us up with the dremel cutting wheel (vice, jig, something that doesn't bleed and scream in case of accidents). Always good to see someone else do something to stick it to the UPS oligopolies.

I used UPC similar or just like this for years. Just drilled hole in battery cover and ran right to car battery. Never had any problems if I only connected it to computer and monitor. Much larger UPC units are available for cheap or free that just need a battery. No mods required. I only use semi-sealed batteries (tops don't come off) for less gassing. And I only use APC brand UPC. Less likely to have problems.

Easy "fitment" neat, it's like “gription" made up yet functional words are the best.

Same crazy $hit I do. I do feel better not being alone 😊

I just need to supply a small load (my little web server + modem & router), so I didn't bother with all that stuff. No fan, no battery box. I just spliced a couple of cables with battery clamps on the ends, in place of the original 7A battery, drilled holes in the UPS box for the two wires, and put the UPS on my desk next to a car battery. (If I'd been intending to power a larger load then I'd have added a fan.) One advantage is that I can swap batteries without shutting anything down. Another advantage is that I always have a fully-charged car battery, ready to go, in case I need it. The first time I had a power outage, it worked fine, but the beeper was intolerable. So, after the power came back on, I removed the beeper. The next time I had a power outage, it lasted 6 hours and 40 minutes! My UPS kept my website up the whole time. Nothing ever smelled hot, and the UPS never got warm to the touch. I clipped a multimeter to the battery terminals, and the voltage decreased by a little over 1v over about six hours. I suspect it was near to shutting down by the end.

Damn you are clued up

Good project. Neat and tidy. Any concern with off gassing from the battery? I didn’t notice mention of it

23:35 FABULOUS PROJECT! I’d have moved the volume pot to the cable side, to avoid having something stick out the top.

The fun thing is there's battery shops that will pay for your old lead acid batteries. So this was just a total freebie in every way!

Great video, I all way wondred if that would work, but I figured the power supply would kill its self trying to charge a car battery.

I used one of these that I had laying around and replaced the internal battery with an 18 amp hour battery. it takes a long time to recharge, but it does work. I didn’t need a fan because I’m using it to run a router that only draws about 10 W. it keeps my Internet up for 12+ hours when the power goes out.

Hey! I think I have this model UPS. Yeah, dead battery, too. ... I also have a stack of that style protoboard. 😀

I have that exact model. I love, though, it needs a battery. I upgraded to a more powerful unit, but I'm still going to replace the old battery in the 550VA

excellent work next time don't trim strands off the wire not that its a big issue but I stick an "ALL" or a pic in there and widen the aperture to fit the wire as its a crimp anyway it may buy you a bit more where losses are concerned if you are looking for every bit. I often upsize my conductor runs for solar to help with losses.

FYI: if you can find the cable to connect this to USB on your PC and download the software you can adjust the runtime and alarm settings as well as thresholds for triggering a switch to battery power such as the voltage min and max. Typically they default to turning off the power after a few minutes to give the PC time to shutdown and maintain a charge in the battery, I changed mine to run as long as possible regardless of the capacity of the battery.

Its alot easier to use self tapping screws for creating pilot holes in plastic when you have no anchor. It is also a lot safer than doing it with a drill. Get screw and hammer. Hit it with a slight tap in the spot you want (this acts like breaking the glaze on a tile.) Then use you cordless screwdriver to do the rest. Great vid by the way.

I wish I was this cool. 😎

Had one of thse where a small amount of liquid got into the inverter side plugs.Popped it open dried the liquids up and for good mesure tightend the loose metal of the plug contatcs.

I've actually done this to the ups that's powering my PC at home, though I didn't open up my ups. I just installed to parallel lawn tractor battery's on it. Though I've thought about using a generator hooked up to the DC side incase of long term use. Maybe solar

"No boom" has me absolutely dying laughing

Originally might have been made “Over Seas”: Improved in 🇺🇸.

Nice! I got a nice free older but high-end UPS (APC Back-UPS XS 1200) of similar design, even with a brand new battery set the previous owner tried changing out. Unfortunately, it appears (reading data from it over APCUPSD with a special USB cable) that it is sensing AC input voltage as being chaotically all over the place (frequently outside the loosest tolerances the firmware will allow to be set) at all times (even when unplugged?), and refusing to switch from battery to line power due to this perceived unstable line voltage. As this sensing appears to take place from a pair of resistor chains from the high-voltage side heading into what I believe is a TS358CS double op-amp amplifying the difference between them (who's other connections are difficult to trace) and thus doesn't contain any components that seem plausible to wear out over time or easy to test, I'm not sure what I can do to fix it, at least not without a schematic to figure out all the other connections going on. Could worn-out electrolytic capacitors be causing the device's power supply to leak enough noise back to where this voltage sensing is going on to interfere with the process? Replacing the through-hole electrolytic capacitors would be a relatively simple matter of ordering similar parts, but if it's not that I have no idea where to start.

I did this with a ES-350 and an 100ah battery to back up my pellet stove and it worked ok without a fan but the internal charger could not bring the battery back up so I had to add a 5A charger. I also just put hot glue in the buzzer to mute it. I've since moved to a 1200VA ups which has a built in fan and it's able to maintain the 100ah battery on it's own (so far).

Great upgrade on an old UPS. How does the charge circuit handle charging the larger batter after it has been fully deleted? Obviously it will have to run at max charge rate for much longer until it reaches the trickle charge voltage. It might have been an idea to have another trigger for the fan to run while the battery is bulk charging.

Hi, great project, may i know what temperature monitor device you re using? Thank you.

this is great! I have the EXACT same UPS and with a dead battery too... might just follow in your footsteps! did you ever make a gerber for the board? or was that just a protoboard I saw?

a small analog clock would be a nice, little and cheap addition to the segments you know you'll be fast forwarding :) it's your first video for me, you got a new sub :D

One thing I question: in the final assembly, isn't your intake fan between the UPS chassis and the battery box, with only a thin channel for air intake?

12:30 I’m thinking of building a custom case rather than modding that one. Just me. Well done! ⚡️

Sir, I was an electrical engineer in the 1990's when I was in the Air Force. I absolutely loved watching this! What a great idea! How much did everything end up costing you? I've only just found your channel, but you definitely earned my SUB with this one, brother. I look forward to reading all the FAQ's below (I knew the Karen's would be screaming about off-gassing, LOL)! Anyway, looking forward to binge-watching some of your other videos. Shalom

yeah i have done the same thing a few years ago,but i started with a bigger metal case UPS,just ran leads out and connected it to a truck battery

I collect these from people throwing them out. I just order new batteries. First thing I do is clip the beeper on the board. I do get good used batteries from a buddy who changes out batteries on emergency lighting fixtures inn commercial buildings.some places change them out yearly.

Soon l’ll be getting an ups son that I can use for random stuff. I’ll probably use it as an inverter in a future mini solar project

Thanks for taking out the time. Quick question, how do I do this with a ups that is 24v and comes with two of those little batteries while I have one 12volts, 75amp car battery, do I have to get an additional battery which I cannot afford right now or can I make one battery work with it?

I did this back in about 1999 to several of my UPS's. I used lawn tractor batteries from Walmart. 20 bucks. Too bad they are much more expensive now. One of my UPS's was a sine wave type that was very expensive and also highly inefficient so it was already equipped with two lead acid batteries. But they had reached their end of life so the company junked it and it became mine. I put two used but still functional car batteries on it. It could hold up my computer for several hours. BEWARE: Most UPS's put out a pseudo sine wave which is sort of a square wave. The problem is the edges of that square produce lots of high frequencies.(See Fourier transform theory.) If that voltage is applied to an iron core transformer like the old wall wart kind(all we had in 1999) that weren't using a switching circuit, then the high frequency eddy currents in the iron core will heat it up to the point that the safety heat fuse opens and the wall wart is dead. Those old wall warts can take that pseudo square wave for 10 or 20 minutes but much longer than that and it's curtains. The newer light weight switching kind are fine with that square wave. And you know what I did don't you? I cracked open that wall wart and jumpered that safety heat fuse and it was back working. I left the plastic case off and always had it in a place where it got plenty of air to cool it off. Safety third.