I had to replace my UPSs a few weeks ago on short notice due to hardware failure, and I ended up getting a few LiFePO4 ones as a stopgap since they were on sale and I'd always wanted to try them. So far, so good. Curious if anyone else has switch to lithium UPSs from lead-acid and how that's going for you.
I have a big 20Ah, 48v e-bike battery that I've used with a sine-wave inverter for standby power, and it's a bit over 11 years old and going strong. So, as far as the batteries in these are concerned, I am cautiously optimistic that they'll last close to the 10 years they're advertised as. The electronics and inverter...we'll see, I guess.
Bonus question: While we're on the subject, has anybody tried those drop-in replacement 12V LiFePO4 batteries for regular UPS's? Supposedly, it says the BMS in them can work with the lead-acid chargers in UPSs and safely charge them, but I'm not sure I trust that.
There's an old thread about someone doing it here: https://diysolarforum.com/threads/replace-apc-ups-sla-batteries-with-lithium.25424/ but sadly he doesn't give any details, or any updates.
It's wierd. APC do a really crappy small one for telecoms cabinets, but none for servers. I would love to replace my APC batteries with lithium ones.
Let us know what ones you chose in the end.
Heh, yeah. That's the part I'm most interested in. I'm sure I could buy the replacement batteries and they'd work fine at first, but after a year? That's what I'm curious about.
I wonder if the lower discharge current capability of LFP batteries is why? That's the one thing I've read fairly consistently about them is that they can't supply the same high current as lead acids but are otherwise superior in every way. Now that you mention it, the only place I've ever really seen LFP UPSs for servers is in the big, central UPSs where they can run batteries in series for a much higher voltage.
e.g. most of the LFP UPSs I see max out at 1000 VA where 1500 is more typical for lead-acid UPSs.
I don't think so. Cheaper batteries have that problem, but a decent brand does not. Check out this one: https://www.powertechsystems.eu/home/products/48v-lithium-ion-battery-pack/48v-105ah-5-38kwh-lithium-ion-battery-pack-powerbrick/ I bought one for my house, and have a 5KW inverter connected to it. Its specifications say that can do 120A drain continuously. I have used it to boil my 3KW kettle a few times in one day (but not often - I usually use the power for other things), and it has been fine.
That's just a limitation of the product, not the technology.