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.
I once asked a salesman for a different product (not an UPS), why they still use lead acid batteries in their products. He said they're easier to replace and readily available... I could hook up pretty much any car battery from the shop around the corner to that machine.
But I'm not sure if I like the failure modes of the traditional UPSes, either. I've seen several badly maintained ones in some smaller companies. And on the next power outage, they last like 6 seconds and are practically useless. And I've removed one lead acid battery that definitely didn't look okay any more. Not sure if that's a fire hazard with that battery type... But there's that. And I'm comparing 20yo neglected devices which I removed somewhere, to their more modern counterparts with better monitoring, better battery management systems etc.
I don't have any valuable insight on LiFePO. Sounds good to me. They generally have some advantages over Lithium Ion. And they're bound to appear in every other electric car, bicycle, some solar installations in the near future. We might as well put them into our UPSes.
I've also read the recycling process is way more complicated for lithium cells. While it's easier to recover the lead. And we have a proper infrastructure for that and 99% of the batteries get returned (or something like that). I certainly hope we make some progress with LiIon and LiFePO as well...