Many "solar power stations" can be used as a UPS, with competitive switching speed. Just not sold under that label. You can even get one made entirely in the US, but it will cost you: https://enphase.com/store/portable-energy/iq-powerpack-1500-...

But yeah, the cheap chinese "power stations" run circles around most UPS capacity wise. UPS market is very complacent.

Seems like an opportunity for someone

No, it's a bad fit. it would be pure marketing. Lipo slowly destroy themselves when charged. Lead acid slowly destroy themselves when not charged.

There are different LIPO chemistries. LFP in particular has little problem with being fully charged. You'll see it get swapped in for lead acid chemistries even in places like car/motorcycle batteries.

If you want an Lithium power supply then the keyword to look for is "LFP".

And LFP is also cheaper per unit energy and less of a fire hazard. Hard to imagine why you would use a different lithium-chemistry in a UPS.

Can't we just not push the lipos to 100% and have the UPS maintain a ~60% charge instead and get a long life span?

Many of these power stations (including the one I linked) are LFP chemistry

Lead Acid as far as I know is about $500 per KWh of usable space due to their depth of discharge being limited to about 50% and then they last about 3 to 5 years if they kept within their 500 cycles at most. Whereas a LiPho battery will last 10-15 years, 6000 cycles and costs about £120 a KWh. So I have no idea how UPS based on lead acid is ending up cheaper, its not based on the battery tech cheapness.

UPS aren't really cheaper.

Sure, up front you're paying very little for that box that can run your PC for an hour.

But over 2-4 years you'll have to replace that UPS after it fails catastrophically in really dumb ways, and that's if you're lucky and it doesn't also burn your house down, whereas a proper storage system will last for a long, long time with more capability.

In my business I've never had a deskside UPS live longer than that.

And yes, we don't buy the ultra expensive ones. That's true.

Do not try this at home, but I replaced the lead acid battery in my UPS with a LFP battery. From what I read online, the charging curves for lead acid batteries and LFP batteries are very similar. The LFP batteries have a slightly higher charging voltage, so I expect my LFP battery to only charge upto about 80% capacity or so due to the charging voltage being slightly too low. I'm hoping the battery will last 10 years instead of 2 or 3 years.

Do not try this at home, as changing battery chemistry is quite ill advised.

Some of the power stations from Ecoflow/Anker/Bluetti are competitive in terms of price and capacity while still having a fast enough switchover for UPS purposes.

They tend to have features that may not be necessary for a UPS (eg solar or DC input), while lacking some features that are more common on UPS (eg companion app to turn your computer off when UPS gets low, although you might be able to rig your own solution)

Eaton and APC at least have models with LFP chemistry, with comparable prices across power ratings. The LFP will be more expensive though due to the increased longevity, at least until lead-acid ones stops being produced.

UPS is kinda different since they are hardly used. I haven't done the calculation but it would guess lead acid is still cheaper?

Problem with Lithium ones is that they tend to be quite flammable. Lead acid is mostly inert I believe?

LFP is a lot safer than NMC. I think it's almost on par with Lead-Acid.

The acid in lead acid is sulfuric acid and if overcharged vents hydrogen gas, thats why they need a ventilated space typically. Sealed lead acid have safety vents that might pop if enough pressure builds.

They are most certainly not inert, they just have well established safety and charging protocols and are not used in very high quantities together because of their low energy density and cycle life.

LFP batteries which have iron phosphate cathodes are very stable compared to colbalt based batteries that tend to have catastrophic failures due to overcharge causing cathode failure. LFP have higher cycle life and are cheaper and typically whats used for storage and application where the loss in erergy density is not a big deal.

Weirdly, none of the many phones, tablets and laptops I've owned have ever caught on fire.

I guess I've just been lucky.

It’s not as much about the risk of failure, as both are safe when the correct safety measures are in place.

But what might happen when they fail - thermal runaway is no joke with lithium-ion, ask any firefighter.

I've had laptop batteries swell up, which is disconcerting to say the least.