My UPS (APC) has faulty batteries (again). 3 years old, already fried. I don’t mind the poor capacity of the PbAc batteries but this life cycle is horrible (2-3y tops).
Can I replace them with equivalent LiFe batteries like the ones you find on Amazon and such with the same form factor?
Or are there LiFePo4 UPS available in Europe?
Different charge controllers are needed. If the ups manual doesn’t specifically support LiFePO4 the answer is no. You’d likely also need to configure it for that charge cycle if supported.
I have no experience with UPSes, but I have used LFP batteries a fair bit.
The main compatibility issue will be the battery voltage and charging system. Most Li-based batteries have slightly higher nominal and charging voltages than lead acid types depending on the cell configuration.
Check the specs on your UPS model to be sure it is compatible and if it is, I’d go with LiFePO4 (LFP) batteries rather than other Lithium chemistries at this time. They don’t weigh as much as the equivalent lead-acid batteries, are roughly the same size for the same capacity and handle deep discharge better than lead-acids. Plus LFP batteries aren’t as volatile as some other Lithium batteries.
I’ve done it successfully for two Tripplite 1500va and two APC 750va UPS’s. They’ve been running for over 4 years now.
I bought a lifepo4 that specifically said it had a lead acid drop in replacement BMS (battery management system).
The only problem I have had was when I had a two day power outage. After running to complete drain ( and they lasted over 2x longer than my older lead acid), the Trupplites wouldn’t charge up after power was restored. I had to pull the batteries and charge them outside the ups to get everything working again.
Under normal use they have worked great.
Lifepo4 works fantastic as a drop in because the peak charge of lead acid is only 80% charge of lifepo4. This means that while you don’t get full capacity out of the lifepo4, it never fully charges which dramatically increases the lifepo4 lifespan.
There are lifepo4 batteries that are drop in replacements for SLA car batteries. But there’s no guarantee that the more sophisticated circuitry in the UPS will accept it. (I’m not exactly sure what they’re using to make it a drop in replacement.) I would look to see if others have succeeded online. That kind of swap is something people would be posting all over YouTube if it works.
It was on YouTube like 6 years ago. I did it 4 years ago and they’ve been running great.
You need to get a lifepo4 that has a lead acid drop in BMS.
Probably not. LiFePO4 keep their bulk at an even 13.7V
Your lead-acid probably floats around 13.5-13.8V. the charger might pulse or occasionally go even higher to desulfate the batteries. That’d either leave your new expensive battery undercharged or worst case damaged (or have the BMS cut it off).
Lifepo4 charges at 14.2. So it’s not only safe, but it means the lifepo4 is undercharged which dramatically increases its lifespan at the cost of runtime.
Not without changing the charge controller as others mentioned, you’ll basically be diy’ing a whole new ups.
Which you can do, and this is a great example (from a few years ago):
https://static.xtremeownage.com/blog/2021/portable-24kwh-power-supply--ups/
You’ve also got options like Eaton for lithium-ion UPSs, keep in mind that they are generally better than APC or CyberPower units and will cost more. As far as your batteries go today, thats (my opinion) the likely reason for the short life - you should get 5 years out of them unless your power is really unreliable. The charge controllers in the small UPSs from APC IMO aren’t great.
I’ve got all lead-acid, but most of my UPSs ive done some degree of work on (just used the casing and swapped the guts, full diy, and a better rack-mount unit I made my own external battery pack for), and they all have gotten 5 years or better so far (about 12ish years in at this point).
My UPS (APC)
https://www.reddit.com/r/homelab/comments/117oa9i/why_is_eaton_ups_so_much_more_expensive_than_apc/
Why is Eaton UPS so much more expensive than APC and Cyberpower?
In what ways is Eaton so much better that it can demand nearly 2x the price?
UK person here, so not sure how it differs country to country, but every APC UPS we’ve had has excelled in utterly trashing the batteries. Where I have to change batteries in an APC every 18-24 months, an Eaton will go five or six years without killing them.
There’s some further discussion talking about how the APC units hold the charge voltage at a high level, and the Eaton ones, once the batteries reach target voltage, bring it back down and only bring the charging voltage up occasionally for brief periods to maintain the charge in the battery.
Why am I not surprised to hear APC is crap compared to Eaton?
A little aside: Eaton does a whole slew of electrical products, including things as “simple” as circuit breakers to electrical assist for large trucks.
Electrical is what they do.
Why am I not surprised to hear APC is crap compared to Eaton?
Keep in mind that this isn’t my personal experience talking here. I also don’t know if the user in question is correct, or if it might be specific to some portion of the respective brands — both make a wide range of UPSes, from inexpensive to pretty pricey. But I did remember reading that, and it did seem potentially germane to OPs problem, so…shrug
Someone with a multitester or oscilloscope or something and some of those units could probably examine further, see what the actual behavior is for a given model.
I have two in my main UPS for over 2 years without issue. Just make sure to buy them with built in BMS so it manages the battery for you.
I’ve heard that yes this is safe, though I’ve only done this with automotive stuff personally
Yep, specially with lower quality UPS the lead batteries degrade in a year or two to an useless state. I doubt you can simply replace them and I wonder about LFP UPSs as well.
I’ve looked into this a bit but not deeply and add to the chorus of no. The voltage isn’t right and the charge controller doesn’t charger properly and it’ll detect charge levels incorrectly - its not like a car where it’s fed a fairly constant 12-14V that can be handled by a BMS and integrated charge controller.
From memory you should also change the charging circuitry if you are changing battery types.
