Eaton 3S 850 UPS problem x 2 (large animated image)

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freitasm

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#322803 23-Sep-2025 17:23

I have three Eaton 3S UPS at home - one 700 and two 850.

One UPS keeps the NAS and a NUC running, another powers the ONT/router/switch combo and the third is in the lounge.

Yesterday there was a power cut in Wellington. It lasted for one hour.

The NAS is set to power down after 15 minutes. After ten minutes of the power cut and checking the WE website for ETA to restore power, I thought I should power down the NAS. I looked at the status for the UPS and it still showed 40 minutes of power left.

But then something happened.

The UPS died. The NAS and NUC went down, not in a graceful way.

I swapped the 850 with the working 700 and then I noticed the other 850 was down as well.

So here is the status:

Eaton 3S 700 - battery replaced June 2022, working
Eaton 3S 850 - bought new June 2022, not working
Eaton 3S 850 - bought new September 2021, not working

When I try to power the UPS it flashes the LED red/green then stops. The Windows application says the batteries are 100% charged and also says no power output to the protected outlets. The non-protected outlets work fine.

I wonder if this is a fault (both units at the same time?) or just time to replace all the batteries (including the 700, just in case)?

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#3418088 23-Sep-2025 20:09

Odd that Google isn't showing me any helpful results when searching for the LED status light behaviour that you show.

Our main experience is with tower server UPS units like the HPE T1000 and T1500 units. We've also supplied a couple of dozen desktop UPS units including 'giant power strip' UPS units like this one. Experience has taught us that the smaller units aren't great at preserving or measuring battery health. All UPS on equipment we manage now get a battery replacement or a whole unit replacement at the 3 year mark, otherwise we risk this sort of situation.

If these were mine, I'd replace the battery in one and give it a try for a few days. Potentially then move that battery to the other unit to confirm it also works as expected before ordering an additional battery.

Eaton replacement battery guide (seems to be missing your exact models!): UPS Replacement Battery Selector, Select a Replacement UPS Or Battery

Our source for replacement batteries for tower server UPS units: Batteries – Shape

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#3418089 23-Sep-2025 20:11

Before I purchased my Eaton UPS I contacted their support with a question, I found them very helpful. I suggest you give them a call or send them an email and get information from the manufacturer.

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#3418216 23-Sep-2025 22:18

I tried talking to Schneider with a similar situation with a 3kVA UPS at work.

One month it actually survived several >1h power outages (according to logs) - it's loaded to about 300VA.

Next month it goes through 'replace battery' to 'internal failure' within about a week.

Schneider were not much use; pulled the battery and opened the tamper proof pack and it was visibly failed. Couldn't get them to confirm whether the error was definitely because of the battery or whether it could be an internal UPS failure.

Ended up replacing the battery and things are fine.

The ability to accurately detect a failed battery appears to be non-existent especially when not loaded to full capacity.

PS: It's usually much cheaper to open the battery pack and buy matching standard batteries from a local supplier than to buy a replacement pack from the manufacturer, even if the pack is only one battery. Better lead time, too.

freitasm

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#3418332 24-Sep-2025 09:32

@Dynamic:

Eaton replacement battery guide (seems to be missing your exact models!): UPS Replacement Battery Selector, Select a Replacement UPS Or Battery

Yes, the 700 and 850 aren't listed.

I bought a HRL1234 from https://upspower.co.nz for the 700 before, so I asked them which model for the 850. I will get on test.

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#3418354 24-Sep-2025 11:04

freitasm:

@Dynamic:

Eaton replacement battery guide (seems to be missing your exact models!): UPS Replacement Battery Selector, Select a Replacement UPS Or Battery

Yes, the 700 and 850 aren't listed

Thats odd, the 3S models show for me (maybe because I hit the link via the AU website?)

Part Number: 52UPS12V34WFR
Replacement Battery for 3S850AU

For reference:

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#3418355 24-Sep-2025 11:10

Anyway, upspower tells me that the same battery works in both 700 and 850 models.

Also, their price is 50% of PB Tech, Ascent and other suppliers. And they are here on Ngauranga Gorge, just five minutes from home.

I have contacted Eaton support asking the meaning of the LED pattern. If they confirm is battery-related, I will get new ones.

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#3418366 24-Sep-2025 12:10

If its easy enough to pull the battery out of those check for swelling, if it is then you know its new battery time.

I've had UPS batteries start to swell after 2 years, admittedly it was in a hot environment.

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#3418367 24-Sep-2025 12:11

Thanks for the suggestion. I already took the batteries out yesterday to make sure the unit was reset. No swelling.

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#3433396 11-Nov-2025 15:17

freitasm:

I have three Eaton 3S UPS at home - one 700 and two 850.

One UPS keeps the NAS and a NUC running, another powers the ONT/router/switch combo and the third is in the lounge.

Yesterday there was a power cut in Wellington. It lasted for one hour.

The NAS is set to power down after 15 minutes. After ten minutes of the power cut and checking the WE website for ETA to restore power, I thought I should power down the NAS. I looked at the status for the UPS and it still showed 40 minutes of power left.

But then something happened.

The UPS died. The NAS and NUC went down, not in a graceful way.

I swapped the 850 with the working 700 and then I noticed the other 850 was down as well.

So here is the status:

Eaton 3S 700 - battery replaced June 2022, working
Eaton 3S 850 - bought new June 2022, not working
Eaton 3S 850 - bought new September 2021, not working

When I try to power the UPS it flashes the LED red/green then stops. The Windows application says the batteries are 100% charged and also says no power output to the protected outlets. The non-protected outlets work fine.

I wonder if this is a fault (both units at the same time?) or just time to replace all the batteries (including the 700, just in case)?

Hi,

I'm thinking of buying one of these to replace my 8 year old Eaton 3S 550 AU (which died two weeks ago in Wellington's electical storm - the three outlets on the battery backup rail are dead). Alternative replacement is the Eaton 5S which is only $35 more.

Three - four years is not very good for battery life. What did you find out with these 3S models? Was it a dud battery in all three?

Thanks in anticipation

freitasm

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#3433410 11-Nov-2025 16:00

I never received a reply from Eaton. Appaling customer service.

I should get a spare battery to try, but with my cancer operation next week I don't think this is something I will test until mid-December now.

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#3433417 11-Nov-2025 16:26

freitasm:

I never received a reply from Eaton. Appaling customer service.

I should get a spare battery to try, but with my cancer operation next week I don't think this is something I will test until mid-December now.

Sorry to hear that you're unwell. Best wishes for the operation. Thanks for responding at such a stressful time.

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#3433418 11-Nov-2025 16:30

No problem at all. Things are progressing well and fast - the surgery is booked, nothing else found, and recover should be quick. I will likely be offline for a couple of days next week, then limited in movement for a week or so, but that's pretty much all.

Thanks for the wishes.

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#3433517 11-Nov-2025 19:23

Fingers cross Mauricio. I'm surprised you didn't get good service from Eaton, they were excellent for me.

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#3433652 12-Nov-2025 10:07

freitasm:

I never received a reply from Eaton. Appaling customer service.

After a couple of emails that clarified that I am in NZ and that I bought the UPS here, I have now been passed off from their US Tech Support line.

First email: "Please note that this email support is intended for the U.S., Canada, and Puerto Rico. I will now move this case to our EMEA [Europe?] team, who will assist you from here."

Second email: "I apologize for the inconvenience. This case needs to be handled by the APAC [I assume that this means 'Asia Pacific'] team. Please reach out to them by emailing your request to TrippLiteTechnicalSupportAPAC@Eaton.com. Kindly send a new email outside of this thread so the APAC team can successfully receive your inquiry. Thank you for your understanding, and I apologize again for the inconvenience."

My unit is a Eaton 3S 550AU purchased in 2018. The fault is that the three outlets on the battery back-up protected rail are dead. The power button does not illuminate. The three outlets on the other rail (not on battery back-up) are working okay, despite the power button not being illuminated. The circuit breaker is not protruding and appears to be fully in.

The battery (DJW12-5.0 12V5.0AH) has never been replaced and it is now 7.5 years old.

The fault occurred after an electrical storm in the area. I do not know if this was the cause because the attached equipment was not being used at the time.

I suspect that this fault may caused by a dead battery but wanted to check with Eaton to avoid wasting money on a replacement battery if there is actually a more serious fault and the entire unit needs replacement.

My questions to them were:

Q1. Do the outlets on the protected rail also go dead if the battery is completely dead?
Q2. If the fault is only that the battery needs replacement, is it normal that the light on the power button is not illuminating?

I will post their response here, once received.

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#3433727 12-Nov-2025 13:22

EMEA = Europe, Middle East, and Asia. We often get lumped in with that; it can be a catch-all for 230V-land.

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