UPS lifetime and recommendation

[ChrisRJ]

Dear all,

My 4.5 year old APC Back-UPS BX - BX700GR just died on me tonight. It had always had very low load (for the last 12 months less than 50 W, less than 100 W before). It is not only the battery, but the whole thing is dead. Is that a lifetime I should have expected?

So I need a new UPS now. The usage is only to power my Internet broadband (DSL) connectivity and a switch that connects the modem+router to the rest of the network. No USB connection or SNMP is needed. Basically a "run until the batteries are empty" scenario. Do you have any recommendations for such a use-case?

Thanks!

 

[Ericloewe]

It's crappy but not unheard of, I had a Back-UPS Pro that seemed to go crazy and die one day, after a not-dissimilar amount of time.

As for recommendations, I'll have to go into read-only mode, as the options have seemed pitiful, short of buying a used APC Smart-UPS and replacing the batteries, leaving you at the mercy of what's available on eBay and Co.

 

[ChrisRJ]

Thanks, @Ericloewe . I have read that it might be because of (too) cheap electrolytic capacitors that were not really up to the job. But I currently don't have the time to dig into this.

 

[joeschmuck]

I had an APC UPS-PRO 1500 die on me after about 10 years. I purchased it for a Home Theater Projector since the bulbs cost about $300 each. When I moved it became my main computer UPS. I had replaced the batteries twice and thought it was the batteries again (3rd time) but it was more, the unit needed to be buried. I loved that unit. Capacitors very well could be the issue but if the capacitor(s) failed, odds are more damage was caused so it's easier to replace the entire unit. I did try to fix it myself but schematics would have helped. I also suspect that as a battery starts failing (due to internal resistance) then the UPS is working harder to keep the charge where it thinks it should be, much more than a trickle charge, and I think the UPS fails at that point. It cannot sustain the high current charging levels.

Think of this one, how many times have you removed a failed battery from an UPS just after unplugging the unit from the wall and the battery was hot. I have seen it several times. That is a lot of current causing that heat.

As for the UPS for your use case, I'd buy something small and simple, a 425VA or similar sized item ($54 and up to $110 USD depending on brand/model). I use one to keep my TV from dropping due to a momentary power drop during storms here. It's cheap and works for me. I guess it depends on how long you want the load to run.

 

[winnielinnie]

It's crappy but not unheard of, I had a Back-UPS Pro that seemed to go crazy and die one day, after a not-dissimilar amount of time.

My 4.5 year old APC Back-UPS BX - BX700GR just died on me tonight.

Not to go off-topic, but is it possible that a dying/failed UPS can actually (ironically) harm your components?

The reason I ask is because I had a simple APC 750VA unit that died immediately after a nearby lightning strike. The three devices attached to it (cable modem, unmanaged switch, and wireless router) all died as well. All bricked beyond salvation. Yet nothing else in the home was affected; not even other electronics plugged directly into the wall, such a smart TV, a printer, a different switch, a few computers, a weather station hub, a DVR, etc. (Even devices in the same room, connected to the same circuit, were unharmed.)

It's as if during its lifetime the UPS did its job at preventing a sudden powerless, and its "surge protection" did its job to protect against daily spikes in voltage from other in-home and external factors. But then when its death came, it's as if it sent out a final "!%#@ YOU!" to the world, and took down other victims with it.

So this has made me wonder if there's any basis to this? That if you suspect a UPS is failing (or about to fail), you should replace it before a catastrophic failure, rather than waiting for too long?

 

[ChrisRJ]

It appears that my problem has just "solved" itself.

My main UPS (APC Smart UPS 750) has just had the second outage under load with a power outage to the attached TrueNAS Core and XCP-ng systems. So I ordered a replacement SmartUPS and will take the old one for the broardbent connection.

Anyway, thanks to all of you for quick support!

 

[ChrisRJ]

Not to go off-topic, but is it possible that a dying/failed UPS can actually (ironically) harm your components?

My guess is that the lightning strike was too much for the surge protection. If that assumption is correct, the UPS did not kill your stuff, it was more collateral damage.

 

[winnielinnie]

My guess is that the lightning strike was too much for the surge protection. If that assumption is correct, the UPS did not kill your stuff, it was more collateral damage.

What perplexed me is that the only damage to any electronic device in the entire house were the three specific devices attached to the UPS. Nothing else was affected by the nearby lightning strike; not even devices plugged into the same room/circuit.

 

[Ericloewe]

Not to go off-topic, but is it possible that a dying/failed UPS can actually (ironically) harm your components?

Possible yes. The specifics will vary...

The three devices attached to it (cable modem, unmanaged switch, and wireless router) all died as well.

Didn't all of those have external power bricks? Here's the thing: A UPS could easily self-immolate and take the power supplies of whatever's plugged in along for the ride but I have a hard time imagining serious damage beyond the power supplies. This all assuming that it wasn't the lightning strike (it may have been, depending on your specific electrical installation).

Things can be interesting with internal PSUs, some devices will have them on the same, single PCB, which can lead to lots of fun damage. Others might have a separate (possibly off-the-shelf) module that just happens to be sitting inside the chassis.

What does this have to do with UPSes killing devices? Well, to kill a PSU, you only have to damage the primary enough that it won't be able to function. You can probably do that with a somewhat-higher voltage without too much effort, with a UPS gone haywire (the highest step on some cheap UPSes goes up to as much as 300 V, in 230 V installations). To destroy what's on the other side of the PSU, you need to ramp up the voltage to bridge the isolation on the transformer, X-caps and PCB (absolute minimum 500 V for any sane design, probably tending towards 1 kV), and damage the secondary and damage whatever the device is doing (further regulation in most cases). That's getting a bit beyond what a UPS can do on its own, especially a 120 V unit - with the vast majority of PSUs these days easily handling 230 V, for obvious reasons, you'd need to go pretty damn high relative to the baseline to damage something.

 

[winnielinnie]

Didn't all of those have external power bricks? Here's the thing: A UPS could easily self-immolate and take the power supplies of whatever's plugged in along for the ride but I have a hard time imagining serious damage beyond the power supplies. This all assuming that it wasn't the lightning strike (it may have been, depending on your specific electrical installation).

Indeed they did. It would have been interesting to see if the devices still work simply by swapping out the adapters with compatible ones. Alas, everything's long been tossed into the trash. (My ISP replaced the modem for free, and I had a spare unmanaged switch on hand. My only cost was buying a new wireless router.) From what I recall, I did not see or smell anything burnt on the power adapters for all three devices.

 

[Ericloewe]

It would have been interesting to see if the devices still work simply by swapping out the adapters with compatible ones.

Probably. It's good to keep a box full of power bricks from junked stuff on hand.

 

[danb35]

No real advice for Chris, but I'm finding it very frustrating that everything on the market is lead-acid until you get into very expensive commercial units (e.g., https://tripplite.eaton.com/smartpr...fepo4-batteries-2u-lcd-usb-db9~SMART2200RM2UL). LiFePO4 batteries are widely available, have a far greater lifespan (both in terms of cycles and in terms of years), have a much higher energy density, and would need only very slight tweaks to the charging profile. They're more expensive than lead-acid, to be sure, but not greatly so. They really should be the norm these days, or at least available at mid-range capacities.

 

[joeschmuck]

1.92kW, that is some power. I wonder how long I could run my HVAC unit on that
But seriously, that would be nice to have that technology in a consumer grade product.

 

[danb35]

But seriously, that would be nice to have that technology in a consumer grade product.

...and there's no real reason it can't be there. Battery charging isn't rocket surgery, and it'd only take small tweaks to the voltages. Yes, the batteries cost more--but I'd happily pay a pretty hefty premium for LiFePO4 batteries, which I shouldn't need to worry about for another 10+ years.

 

[joeschmuck]

When it comes to battery charging these days, you need to do it correctly. I use LiPo batteries for my RC Airplanes and there are very specific charging voltage & current for these batteries, I'm not sure about LiFePO4 batteries specifically but I know there are separate chargers for that, well I have a charger that can charge many different type of batteries, including the LiFePo type.

As you said, not rocket science. I sent three of my newer guys to a 3 day training session on Ballistic Guidance Systems. They told me that for first few hours was good stuff but after that the engineers were just way over their heads. I guess someone asked this woman to explain something a little simpler and she went off and pointed to the board and said something like "the quadradic something something formula is right there, it's obvious." I had to laugh. I would have loved the course. I don't like math but couple it to something like this and I'm right there. Yea, off topic.

 

[Ericloewe]

Even at commercial scales it's ridiculous. One of our sites has multiple fancy building-scale UPS systems (multiple buildings...) that only need to bridge things over while the backup diesel generator(s) get up to speed. Shelves upon shelves of lead-acid batteries that need to be replaced every handful of years. The labor to do the extra swaps would probably offset any cost difference remaining after the longer life is taken into account...

 

[danb35]

I'm not sure about LiFePO4 batteries specifically

They're very close in this regard to lead-acid (four LiFePO4 cells are nearly a drop-in replacement for a 12V lead-acid battery), which is one of the things that (IMO) makes them very attractive in this application--if you can just tweak the charging voltages a little bit for optimal performance, you'll be fine. The other is that they aren't unintended incendiary devices; LiFePO4 don't catch fire when they're abused like LiPO can.

 

[joeschmuck]

Interesting. I found one that has the form/fit/function. Of course I'd keep looking but the fact that someone has it out there now, my next set will be these after I do some rear research on them.

Dakota Lithium 12V 14Ah LiFePO4 Battery Twin Pack

Lifepo4 twin pack of 12V 7 Amp batteries as replacement of UB1280 12V 7Ah, 9Ah, and 10Ah SLA batteries with 2X the power, 1/2 the weight, 5X the lifespan.

dakotalithium.com

 

[ChrisRJ]

A few more posts and will start contemplating getting into the business of building UPSes ;-)

 

[Constantin]

A few more posts and will start contemplating getting into the business of building UPSes ;-)

i did a few with the help of Pico-box. They offer some neat systems and pre-built solutions. I would really like to see more UPS’ that also work directly with an ATX PSU to cut out the AC-AC conversion step to significantly boost effiency, especially at low loads.