Probably just a case of replacing the batteries, but if you want to think out of the box: there are some hybrid inverters for solar systems that offer a UPS mode. So you could combine a home solar system with modern lithium batteries with your homelab needs for a better UPS.
this post was submitted on 16 Dec 2023
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This is the $10k solution to the $100 problem I was looking for, thank you for the idea.
"My dear significant other, the server's battery backup is dying -- I'll be on the roof."
I second this idea, if it's feasible. As noted elsewhere in this thread, the lead-acid batteries in UPS units have a limited lifespan, even if not regularly drained. Solar and off-grid enthusiasts have determined that parity between overall lifetime cost of lead-acid versus lithium batteries was reached years ago, and now it's firmly in lithium's favor, mostly due to the greater number of recharge cycles.
Contraindications for lithium batteries would include:
- high local costs for lithium battery packs
- lack of space for the hybrid inverter, as they're usually not rack-mountable
- the homelab drops below 0 C (32 F), in the specific case of LiFePO4 cells
That said, breathing life into old equipment is usually more environmentally friendly than acquiring new equipment.
The primary concern is switchover time. A purpose-built UPS can switch in about 10 microseconds. Those large "solar generator" battery packs switch in about 30 microseconds. That might be fast enough, but it's not guaranteed to be fast enough like a UPS is.
Well, if that is really a concern, you can keep the old UPS with not so good batteries still connected to cover that 20 microseconds difference.
But it is unlikely to matter in a homelab.
Did y'all mean to say milliseconds, and not microseconds? Sub-millisecond power loss would be less time than one AC cycle, whether 50 or 60 Hz.
Anyway, I do recall seeing some enterprise gear specifying operation through a drop in AC power lasting two cycles, precisely to cover the switch to UPS power, at least for 60 Hz power. So up to 33 milliseconds. A cursory search for hybrid inverters online shows a GroWatt with "<20ms" switchover, so this may be fine for servers and switches, when the inverter is operated without any solar panels.
For consumer grade equipment, all bets are off; some cheaper switch-mode power supplies do very weird things under transient conditions.
Dang, you woke Murphy. I hate it when that happens.
UPS batteries are only rated for a few years' use, so you probably are due for replacement.
I'm personally running an SMX2000RM from APC. I added a NMC2 to it for monitoring, because I'm crazy like that. I picked up the SMX2000 because I'm running old enterprise gear for my homelab. I have a half-loaded Dell C6100, a Dell R710, a Dell Powervault NX3200, a Dell R630, and a slew of networking devices, plus some utility systems, including a miniPC running Home Assistant, several Raspberry Pi's (usually using PoE), a few PoE switches, two gateway/firewalls, modem, at least one Cisco ISR router, and a Synology NAS as part of my setup.
Very quickly, new house, bought the R630 for "home operations" which is running some internal to the home systems, such as a backup DNS, some game servers, and PCNS, all on top of VMware ESXi 6.5 free. I have the c6100 (two nodes), and the R710 running ESXi 6.5 from vMUG advantage, which is running my lab servers, including a windows domain (there's a domain GC replicant server on the R630), Exchange, several Linux nodes doing multiple things, some windows server based gaming hosts, Plex, netbox, and mediawiki for documentation, as well as a LibreNMS for monitoring. Home Assistant is on it's own Core i5 mini pc (either Dell or HP, I forget), which runs my new home automation z-wave network, another mini-pc running DNS (I just wanted a dedicated non-VM system for DNS, so I didn't have to struggle without it while I got VMware working properly after a power loss), and the NAS is for personal backup storage, just a two-bay (8TB drives in RAID 1) for my PC and my SO's PC.
I didn't want all of that to go down as soon as there's a power blip, and the APC SMX2000 was a good fit, considering we're consuming ~11 Amps on the 20 Amp circuit I installed specifically for the UPS (~1300W). I want to get a second one, and redundant power set up for everything, including networking, on the second UPS (I'll be buying another SMX2000 for the purpose), with one feeding the primary power port of everything (or PSU1 on the servers) and the other feeding all the backups (or PSU2 on servers), and I want to add battery expansion on all units, for a total of 6 battery packs across all units, and 4000VA of power available, each UPS will have it's own dedicated 20A receptacle.
The main reason I chose the SMX2000 is that it has a NEMA L5-20R port on the back, which I connected a 0RU vertical PDU (managed, the APC AP7930), which has a NEMA L5-20P connection for the source, and provides 24x NEMA 5-20R ports. The plan is to have two, one for each UPS. I bought the UPS off of Ebay without a battery and picked up a battery from a local supplier (non-APC battery, but a drop-in replacement, with all the APC fittings).
Specifics:
UPS: APC SMX2000RMLV2U NMC: APC AP9630 Battery: SMX2000RMLV2U compatible pack from upsbatterycenter.com or upsbatterycenter.ca (I'm in Canada, so it was .ca for me - APC's SKU for the battery is APC RBC117) PDU: APC AP7930
The UPS is capable of putting out ~1800W. My alternative was the SMT1500 or SMX1500 (I have several of the former laying around with dead or missing batteries), but the models I have don't have any 20A outputs since they can only handle about 15A, I really wanted to go 20A for this, so I sprung for the 20A capable version, mainly to future-proof my power delivery for the rack, so I don't have to worry about what I'm putting in there. Before moving, I had two SMT1500 units, one was rackmount, so the equivalent 1500VA APC rackmount version of the same, and they only had to feed a modem, switch, and the C6100/R710. I added a lot to the system when moving to this house, partly because this is our "forever home" and I wanted to kick things off right. I put the PDU on the side of a new 42RU rack I purchased specifically for the house, and rackmounted everything at the same time. A lot of thought went into which products to buy, I didn't want anything brand new, and I didn't want anything I would have to spend a fortune on to get working. The biggest expense through all this was the new networking hardware for the house, second biggest was the new battery pack, but thankfully UPS battery center is relatively inexpensive for that (still ~$400 for the battery alone, ouch). We have pretty cheap power here ( $0.182 per kWh on-peak, and $0.087 off-peak, in Canadian dollars), so I'm not overly concerned about energy use. I just don't want the system to go down as soon as the power has a hiccup. unfortunately, my power provider has had several outages in the past year that lasted much longer than my battery lasted, so I'm thinking to look into solar or generator backup to keep at least my rack powered up, and maybe fridges and stuff. That's beyond the scope of your question so I'll just leave it at that.
The key here is: how much are you powering with this and how long do you want it to last. If you're like me, and have a decent collection of things that need to stay on, a larger UPS like the SMX2000, plus a battery expansion may be the way to go, if you have less stuff but need extra run-time, maybe a smaller 1000 or 1500VA unit with a battery expansion is fine, or if you need protection against just small interruptions in power, maybe forego the added pack. It really depends on the power delivery in your area and how much you're drawing. Part of the reason I picked the SMX2000 was because it had a connector for an external pack (along with the mentioned NEMA L5-20R), so I can expand the pack later. The add-on cards were a big plus for me, but I would have been happy with any network management whether integrated or not.
A big note from me, if you're looking at (especially used) APC gear, is that you will want to make sure you apply any and all available firmware updates as soon as you can, since a lot of stuff on the used market gets deployed as soon as it's received, and doesn't get touched apart from that; once it is decommissioned for sale on the used market, nobody bothers to update it prior to sale, so update it as soon as you get it. This is especially true for the NMC modules, the interfaces had a complete overhaul during their useful life, especially for the NMC2, making it far more stable and far more capable of a unit for monitoring the UPS. I'm sure this is true for other vendors, but I haven't really dealt with too much from Eaton or CyberPower to know (My employers so far have used APC almost exclusively, which is why I have a handful of SMT1500's, all of which were destined for the junk pile after the battery went bad).
If you want to spend a bit more to buy something new, I would recommend something based on Lithium, as the majority of older UPS units use lead-acid, usually AGM. Lead-acid is great for cost, as the batteries are usually pretty cheap, but Lithium should last a lot longer, I expect to replace my Lead-Acid pack in my SMX in another 2-3 years; lithium should last 5-10 at least. Up to you though.
Good luck.
I'm using an APC 3000 that I got with no batteries.
Your choice should depend on load and needed run time. Mine is around 1200 watts 😮💨, so I need higher VA rating.
I also took out the stock 12 amp hour batteries and I use much larger ones. Don't consider that unless your unit is managed, actively cooled like having fans, and can do thermal shutdown.
People have tried this on the cheaper home use products and burnt their house down because the cheap products are designed for the battery to die before the unit gets so hot it fails and burns. Then some kid extends the run time way past that with car batteries. 🔥
Dang, that thing is the bees knees!
Would make more sense to replace just the batteries rather than the whole unit IMO. Looks like it takes standard 12v 7Ah sealed lead acid batteries, so should be doable for under $120 (if you buy them individually and use the existing battery harness)
I have three other UPSes, but none of them are as good as yours lol:
- APC SUA1500RM2U - was a great online rackmount unit, stopped using this a few years back because of its tendency to overcharge batteries without a charge controller ADC calibration mod. It wrecked my last battery pack bad 😭 plan to convert it to LiFePo4 and put it back into service 🤞
- Zigor Ebro - cheap and cheerful line-interactive UPS for the modem, network switch and CCTV cameras. Switchover time is pretty much instantaneous, worth every cent paid and has kept my network up through many outages
- Cyberpower UT650 - A temporary offline UPS to hold the server gear specifically until I get the APC back in service. Honestly not worth the cheap price, the switchover delay is long enough to shut off anything that's not a server PSU with massive bulk capacitors
Edit: fix bullet list formatting