I live in a cellular dead-zone that is prone to frequent power outages so I am highly reliant on fiber Internet for both voice and data. My telecom backup power supply uses a discreet charger-battery-inverter setup. The battery in the middle is rated for 125AH at 12v and is a deep-cycle flooded lead acid (not AGM). It only powers my optical network terminator, firewall and POE wi-fi. It keeps me connected for days, not hours.<p>Sourcing a proper deep-cycle battery requires a bit of research.<p>Simply splicing a big-ass battery onto a consumer grade UPS won't work well, the little battery charger might not be able to fully recharge the new battery. The charge-discharge profile is all wrong.<p>Enterprise grade UPSs are not optimized for battery longevity, they are designed to recharge quickly and maximize runtime, both to the detriment of the batteries. APC in particular is notorious for overcharging batteries which can cause swelling and eventual rupture if they are not replaced on a regular basis. Also older APC "SmartUPS" would power off your load if you tried to use a regular serial cable to manage them. Surprise!<p>If you are looking for something robust for home use I suggest a reconditioned off-lease Eaton 5PX2000 with as many external battery packs as you want. They support network management, the front panel is actually useful, and they can be programmed to maximize battery life rather than runtime. They require a 20a 120v circuit but unless you are loading it up to more than 75% capacity you can get away with a regular 15a plug and an adapter.
I think that what the author is really looking for is a battery inverter setup and this is quite a mature market. A lot of countries out there do not have stable electricity supply and these things work for all appliances. Something like this (<a href="https://bluettipower.co.uk/products/bluetti-ac500-b300s-home-battery-backup" rel="nofollow">https://bluettipower.co.uk/products/bluetti-ac500-b300s-home...</a>) although there are a huge range of brands and prices in this space.<p>Pc UPS’s are underpowered and the market is so swamped with cheap garbage as the rant suggests that it is difficult to find anything decent.
> UPSes could be designed with the kind of deep-cycle gel batteries used for marine applications like trolling motors to last even longer and be even more reliable.<p>Don't put a deep-cycle SLA or gel-cell battery in your UPS. It will last a much shorter amount of time (2-3 years vs 5+). I do not remember the specifics but it has to do with how big the plates are and how thick the internal connections are in the battery. Designing this chemistry of battery is about trade-offs and unless you greatly oversize the cells and do your own install externally it will wreck your battery longevity.<p>If you want to maintain spec in something like an APC UPS, buy CSB batteries (which is what APC slaps their sticker on) and get something from their GPL line <a href="https://www.csb-battery.com.tw/english/01_product/00_overview.php" rel="nofollow">https://www.csb-battery.com.tw/english/01_product/00_overvie...</a><p>The real disruption for UPS's are the switch from SLA to LFP cells, but power density isn't as good so they need to be sized up a decent amount to handle standard loads. But the chemistry is a ton better.
Yes, they are annoying. And you don't always know when your battery is reaching end of life. After having to take a last minute flight to fix a problem caused by a brief power outage I decided to mod the UPS to run off of deep cycle marine batteries. This is a 1500W APC unit. I picked up a couple of the biggest batteries they had at walmart, cut a hole in the side of the UPS, soldered in some 2 AWG wire, and connected the batteries in series with some ring terminals. The batteries charge up fine and they have gotten the servers through several multi-hour outages. It's coming up on five years now and they don't have the capacity that they used to. I'll probably replace them soon.
What the author wants exists, just not by the names that the author is likely searching for.<p>Victron makes combination charger-inverters that takes power from the grid and keeps separate batteries topped off and also supplies AC power via inverter.
They sell these as their 'Multigrid' and 'MultiPlus-II' products and are populat setups for boats, where you have shore power but need to be able to unplug the shore power at any time and keep things going.<p>It's also a feature of quite a few cheap hybrid solar inverters now- they can charge batteries from mains if there is no PV input.<p>These work as a UPS but you do constantly run the load thru the inverter, thus your are taking a small efficiency hit; however it is truly uninterruptible. There is no 'switchover' time, which is also what makes a lot of UPS hardware so specialized- many are doing mains switching in essentially 1 cycle of 50/60hz mains power. Theres all sorts of stuff that goes with that.<p>Meanwhile, charger-inverter combos ditch having to deal with that by just going AC-DC to battery and then DC-AC. You always have clean uninterrupted power from the inverter. This used to fuel reliability concerns but these days much of this hardware is in applications running 24/7 for years now.
The funny thing here is that the "power station" market has this quite solved. Comes with an app minimum usually, which at least is a start for reverse engineering. If you're lucky you might even get a local diag socket. Unfortunately this comes with the usual IoT issues, but at least you can watch things. With better transfer hardware youd have a much better user experience for upses. I wonder why no one has done this yet.
> that could be assembled cheaply in a makerspace from off-the-shelf components, an Arduino-class microcontroller, and a PROM.<p>Excuse me? You can get off-the-shelf batteries (although LFP batteries with real BMSes are not actually interchangeable, sadly). But you also need the power electronics, and you should not be doing <i>that</i> as a DIY project unless you really know what you’re doing.<p>I would look to the off-grid/RV space for disruption. For example, here’s a “portable power station” for $600. It costs about 2x as much as a random 1500VA APC UPS I looked it, except that it can deliver twice the actual power (if your UPS is powering a modern power-factor-corrected PSU, you just need watts and the VA isn’t a big deal, and APC is cheating their specs by including unnecessary reactive power capacity in their headline number) and <i>20x</i> the energy storage and thus runtime. APC tries hard to obscure very low capacity of their batteries.<p>No one will buy an off-grid setup that can barely power an espresso machine long enough for a single shot.
Anedoctaly, just last month, my APC UPS started complaining that the battery was dead.<p>I bought a 3rd party battery replacement (12V), opened the unit (which is not made easy by APC) and was getting ready to replace the batteries, when I measured the current and it was 12.5V. The replacement one, measured 12.3V<p>I still have no idea why it's complaining the battery is going bad.
Pro-tip: don't buy your UPS online, buy at a local store with a reasonable return policy (e.g. CostCo).<p>I have had duds across three major brands (e.g. die within a year), and not having to ship the product back to the OEM will save you time and money.
As far as battery chemistry, SLAB is a cost tradeoff against your "threats". Our threat is midwestern storms in the spring that cause power interruptions. These are usually momentary (10s) or 30m or less. Anything longer and we'd send people home for the day. Preventing a network reboot during those momentary outages is the goal. Extended runtime just isn't needed, but a decently sized UPS can power one our typical floor racks for about 2-4 hours. We're likely only going to ever deploy SLAB because it's so danged cheap for something thats only used a handful a times a year.<p>I've found that Eaton UPSs pretty much knock out a lot of the concerns listed. I've got 9 of them deployed for floor/closet racks and a raspberry pi to interrogate the UPS with Telegraf, and those are shipped to an InfluxDB instance. Back in the day we would have used SNMP, but that isn't cool anymore... I also have recently deployed a few over the higher end Cyberpower UPSs to see how they do long term (these are a little bit of a meme brand it seems like).<p>That all being said, the lower end Eaton UPSs do not have a way to "Remote Test" (basically they lack a relay to isolate from mains and take the load onto battery). Higher end UPSs can do these commands over USB. One of the help desk tasks is once a quarter, visit each UPS and yank the power for 2m while Telegraf measures the battery drain stats. Not a huge problem, but a mundane task.
APC has gone downhill in the time I've been a sysadmin. Eaton is the way to go for commercial units. Don't purchase anything without a bypass or else the UPS will be dead when the battery dies, as decent UPSs operate in on-line mode.<p>I am concerned about newish implementation of li-ion cells in commercial UPSs. They are not designed to stay at capacity for a long time. That coupled with the volatility of li-ion, means there may be more datacenter fires in the future.
I think whole-home battery backup (charging from solar panels on your roof) using more modern battery chemistry is probably a better solution if you're able to do that.