UPS not working

[JMaia]

I have a UPS that I bought 3 years ago. The battery recently started to not hold power for a long time, so I decided to purchase a new one. Unfortunately, I think I may have damaged the UPS when I replaced the battery, or maybe the new battery is not compatible with UPS and may have damaged the main unit.

After assembling everything with the new battery, I tried connecting to the AC, but a amber/yellow light keeps flashing and nothing gets power when connected to the UPS. At first I thought maybe the battery is charging, but i left it 1 night plugged in and next morning everything was the same.

I also tried with the old battery again, but the same thing happens: only amber light flashes and UPS does not give power to anything thats connected to it.

 

[Diver300]

I think that the yellow flashing light means that the battery is charging, but that should stop soon. The fact that it continues flashing means that it's probably not charging.

Can you measure the voltage on the battery when the light is flashing?

 

[JMaia]

Do you mean DCV or ACV on the multimeter? In ACV it reads 26.6, in DCV it reads 12.6

 

[sagor1]

Batteries are always DCV.
12.6 likely means it is not charging, as a charge level should be over 14VDC, and float level around 13.6V once fully charged.
If something happened when connecting the new battery, like reversed connectors, you may have blown a fuse or something else in the charging circuit. Check the circuit board for any blown fuses.

 

[JMaia]

Here is a photo of the internal circuit board. What and how should I test? Also there is a fuse I can replace from the exterior. The UPS even came with 2 additional fuses to replace. I tried swaping the fuse with a new one, but the same thing happens (I think if the fuse was blown, not even the amber light would flash).

Circuit board


The slot where I can replace the fuse


2 additional fuses

 

[rjenkinsgb]

Do you mean DCV or ACV on the multimeter? In ACV it reads 26.6, in DCV it reads 12.6

If you are reading 26V AC across the battery, it's likely an unsmoothed charge circuit - and the "new" battery is dead, either faulty or actually an old, worn out one.
(Or one that has been in storage far too long and died / sulphated up from lack of use).

Interestingly, I cannot find any place selling that "new" DSK 10362 - every listing I've found shows as not available / discontinued; or used..

 

[JMaia]

If you are reading 26V AC across the battery, it's likely an unsmoothed charge circuit - and the "new" battery is dead, either faulty or actually an old, worn out one.
(Or one that has been in storage far too long and died / sulphated up from lack of use).

Interestingly, I cannot find any place selling that "new" DSK 10362 - every listing I've found shows as not available / discontinued; or used..

DSK Batería Plomo AGM Sellada VRLA Alta Descarga (UPS-SAI) 12V 7,2Ah : Amazon.es: Electrónica

DSK Batería Plomo AGM Sellada VRLA Alta Descarga (UPS-SAI) 12V 7,2Ah : Amazon.es: Electrónica

www.amazon.es

The UPS always worked when plugged to electricity, even if the battery was fully discharged. Now nothing works when plugged to the UPS, even a small table lamp. That's why I think I may have damaged something when I swapped the old battery with the new one.

 

[sagor1]

If you swapped the battery "properly", red to +, black to -, nothing should have been damaged. A replacement battery that is "dead" would prevent it from charging of course, but should not damage anything unless you did some battery swapping with the unit still plugged into the wall.
Many UPS still want to see a battery, even if it has low voltage, before they will start up.

 

[JMaia]

If you swapped the battery "properly", red to +, black to -, nothing should have been damaged. A replacement battery that is "dead" would prevent it from charging of course, but should not damage anything unless you did some battery swapping with the unit still plugged into the wall.
Many UPS still want to see a battery, even if it has low voltage, before they will start up.

I'm pretty sure I didnt swap the red and black cable, and the UPS was not plugged in to the wall ,but maybe I letf the ON button on the UPS plugged in? Maybe it created a short circuit?

Anyways, I'm willing to test the board with multimeter to see if the UPS is salvageable.

 

[Diver300]

If you are reading 26V AC across the battery, it's likely an unsmoothed charge circuit - and the "new" battery is dead, either faulty or actually an old, worn out one.

I thought that when the OP mentioned 26 V ac across the battery. However, some multimeters will read about that when set to "ac" and connected to a 12 V dc source.

If the battery is not connected to anything except the multimeter, and the multimeter reads 26 V ac or so, then that is the multimeter, not ripple.

Other multimeters, when set to "ac" will read 0 V when connected to any battery.

 

[sagor1]

OP says he gets a reading of 12.6V with meter in DC mode. That means the battery is not charging, at least not enough yet. Those batteries require over 14VDC for charging voltage. In "standby", they should read 13.6V.
Charging voltage may be DC pulsed, looking like AC, but then maybe not...

 

[rjenkinsgb]

The UPS always worked when plugged to electricity, even if the battery was fully discharged. Now nothing works when plugged to the UPS, even a small table lamp.

There is a big difference between it seeing a low battery and no battery - a faulty one can appear totally open circuit.

Do you have a 12V lamp (eg. car headlamp bulb) that you can connect across the battery, to see if it can provide significant power?

Disconnect it from the UPS first!

If it can light a lamp like that for a significant time, the battery should be OK.
If no light, or only a second ort two, it's dead. (They are supposed to be supplied fully charged - the are wrecked if stored flat for long periods).

 

[JMaia]

There is a big difference between it seeing a low battery and no battery - a faulty one can appear totally open circuit.

Do you have a 12V lamp (eg. car headlamp bulb) that you can connect across the battery, to see if it can provide significant power?

Disconnect it from the UPS first!

If it can light a lamp like that for a significant time, the battery should be OK.
If no light, or only a second ort two, it's dead. (They are supposed to be supplied fully charged - the are wrecked if stored flat for long periods).

Using a cheap 12 v lamp, both batteries work:

 

[rjenkinsgb]

A tiny lamp that takes a trivial current does not prove much, unfortunately.

That's why I suggested a headlamp bulb - it would put a decent load on the battery (5A or more), to show if it's internal resistance is high.

 

[JMaia]

I managed to get a car headlight and test them on the battery:



The light is very strong on the new battery, but considerably weaker on the old one. I left them on for 5 minutes each time, none ran out of juice.

 

[rjenkinsgb]

OK, so the new battery does appear to be good, unfortunately..
(It would have been a lot easier to get it swapped than faultfind the UPS).

Does the battery voltage increase once its connected to the UPS, and teh UPS is connected to power?

 

[sagor1]

You have two 30A fuses (green) where the black battery lead comes in. Are those still ok, or are they blown (open)

 

[Ramussons]

Your problem is that the old battery did not have enough capacity to run the ups for long. But it was still working.
Put it back (if you still have it) and see whether everything works as before. You will then know the faulty component - New battery or the UPS.

 

[JMaia]

Sorry for the late response, but sometimes life gets in the way.

OK, so the new battery does appear to be good, unfortunately..
(It would have been a lot easier to get it swapped than faultfind the UPS).

Does the battery voltage increase once its connected to the UPS, and teh UPS is connected to power?

I measured the new battery using DCV with multimeter, 12.6 when not conected, and also 12.6 when connected to UPS with power on.

You have two 30A fuses (green) where the black battery lead comes in. Are those still ok, or are they blown (open)

They don't appear to be blown, at least upon visual inspection. Should/how do I test them with multimeter?

You're talkin about these ones, right?

 

[rjenkinsgb]

Pull them both and check for continuity, the resistance should be near enough zero (about the same as with the meter leads connected together).

They appear to be blade style fuses, which should just pull vertically out of the holders.