4 ms·

Lead acid is used for most UPSes. Lithium ion is bad battery type for UPS since has lower cycles and safety, and power density doesn't matter. LiFePO4 would be

Lead acid is used for most UPSes. Lithium ion is bad battery type for UPS since has lower cycles and safety, and power density doesn't matter. LiFePO4 would be perfect, with good cycles, current, and safety. But manufacturers don't use it. Maybe they haven't redesigned after the price dropped. Or maybe cause prices is still too high. I think LiFePO4 would be most useful for rack mounts, or small UPSes that aren't possible with lead acid.

soneil 3y ago
Lithium in smaller UPS is mostly stuck in a marketing gap at the moment. Generally lithium UPS win in a 10-year TCO, but SLA wins in up-front costing. Which leaves us with two issues - most consumers look at the sticker price not the TCO, and no-one wants to market their products as "Our lead acid offer only /looks/ cheap, until you see what we charge you for consumables!"
mardifoufs 3y ago
Regular Li ion has more recharge cycles than most lead acid batteries that come with UPS. Even high power density liion still usually has 4-500 recharge cycles before reaching a maximum of 80% SOC vs the original capacity. With smarter power management you can get away with much more (for example, if you don't fully cycle the battery)
ssl-3 3y ago
LiFePO4 can be had in the "portable solar generator" space, and some of them have enough input/output capacity to function as a usable UPS. All that they lack is comms for status and automatic shutdown. It seems like a fairly recent shift -- heck, the whole solar generator concept is a fairly recent shift -- but maybe it's an indication that LiFePO4 devices are becoming more common in the consumer space.
- simpaticoder 3y ago
  Hey, thanks very much for the tip! I did some (random) searches and found, for example, this 7 pound device[1] that offers 300W output, 256Wh capacity, and 30ms failover at $180. Seems like a great little device that could serve a dual purpose as both a UPS and also a camping/project power supply if you can't have/don't want a gas generator. They claim a 10-year lifetime of the battery and 80% capacity after ~3000 cycles, which seems hard to believe, but maybe LiFePO4 is really some sort of miracle material. https://www.ebay.com/itm/166440776366 https://www.ebay.com/itm/166440776366
  - ssl-3 3y ago
    No, LiFePO4 is actually pretty excellent in that way: It's long lasting, and not harmed nearly as much by charge/discharge cycles as many other types. 3,000 cycles is not an unreasonable claim, and it's a lovely chemistry in that way. (It also tends not to self-combust.) It has other tradeoffs, though, like being physically large compared to a lead-acid battery of similar capacity (or, say, a bunch of 18650s). And like other Lithium-based cells, longevity is maximized by never charging it to 100% and leaving it there long-term -- which, unfortunately, is probably not what Ecoflow is doing. (Ideal long-term state-of-charge is closer to somewhere between 50 and 80%.)

soneil 3y ago

Lithium in smaller UPS is mostly stuck in a marketing gap at the moment. Generally lithium UPS win in a 10-year TCO, but SLA wins in up-front costing. Which leaves us with two issues - most consumers look at the sticker price not the TCO, and no-one wants to market their products as "Our lead acid offer only /looks/ cheap, until you see what we charge you for consumables!"

mardifoufs 3y ago

Regular Li ion has more recharge cycles than most lead acid batteries that come with UPS. Even high power density liion still usually has 4-500 recharge cycles before reaching a maximum of 80% SOC vs the original capacity. With smarter power management you can get away with much more (for example, if you don't fully cycle the battery)

ssl-3 3y ago

LiFePO4 can be had in the "portable solar generator" space, and some of them have enough input/output capacity to function as a usable UPS. All that they lack is comms for status and automatic shutdown. It seems like a fairly recent shift -- heck, the whole solar generator concept is a fairly recent shift -- but maybe it's an indication that LiFePO4 devices are becoming more common in the consumer space.

simpaticoder 3y ago
Hey, thanks very much for the tip! I did some (random) searches and found, for example, this 7 pound device[1] that offers 300W output, 256Wh capacity, and 30ms failover at $180. Seems like a great little device that could serve a dual purpose as both a UPS and also a camping/project power supply if you can't have/don't want a gas generator. They claim a 10-year lifetime of the battery and 80% capacity after ~3000 cycles, which seems hard to believe, but maybe LiFePO4 is really some sort of miracle material. https://www.ebay.com/itm/166440776366 https://www.ebay.com/itm/166440776366
- ssl-3 3y ago
  No, LiFePO4 is actually pretty excellent in that way: It's long lasting, and not harmed nearly as much by charge/discharge cycles as many other types. 3,000 cycles is not an unreasonable claim, and it's a lovely chemistry in that way. (It also tends not to self-combust.) It has other tradeoffs, though, like being physically large compared to a lead-acid battery of similar capacity (or, say, a bunch of 18650s). And like other Lithium-based cells, longevity is maximized by never charging it to 100% and leaving it there long-term -- which, unfortunately, is probably not what Ecoflow is doing. (Ideal long-term state-of-charge is closer to somewhere between 50 and 80%.)