Buzzing noise when UPS is running off battery?

[Anonymous user]

I have the RS1000 and recently put new batteries in. The positive and negative connections are using the original adaptor, but the link between the batteries that connects them in series is soldered on there as I lost the original cable. I don't know if this has anything to do with the problem, but if necessary I guess I can find a thicker wire and solder it on there.

Now the problem is that when the power goes off and the UPS is on battery, the computer starts buzzing. It's an electrical sort of buzzing. I'm not sure where in the computer it is, but it's definitely from the computer itself, not the UPS.

So I'm thinking that there must be some problem. It's quite a loud buzzing. I'd usually assume that there was a loose wire or something so the electricity supply wasn't proper. But as far as I can see, the wires are fine.

Also, when I was testing the batteries before I connected them all up properly and put them inside the UPS, I made the series connection using a 6mm copper wire. The buzzing still happened then, so I don't think it's the current wire's problem.

What do you think could be causing this? If you have any ideas then I can try and troubleshoot the problem.

Thanks

[Anonymous user]

I have the RS1000 and recently put new batteries in. The positive and negative connections are using the original adaptor, but the link between the batteries that connects them in series is soldered on there as I lost the original cable. I don't know if this has anything to do with the problem, but if necessary I guess I can find a thicker wire and solder it on there.

Now the problem is that when the power goes off and the UPS is on battery, the computer starts buzzing. It's an electrical sort of buzzing. I'm not sure where in the computer it is, but it's definitely from the computer itself, not the UPS.

So I'm thinking that there must be some problem. It's quite a loud buzzing. I'd usually assume that there was a loose wire or something so the electricity supply wasn't proper. But as far as I can see, the wires are fine.

Also, when I was testing the batteries before I connected them all up properly and put them inside the UPS, I made the series connection using a 6mm copper wire. The buzzing still happened then, so I don't think it's the current wire's problem.

What do you think could be causing this? If you have any ideas then I can try and troubleshoot the problem.

Thanks

[Anonymous user]

The battery-to-battery connector is usually where the fuse is. If you replaced a fuse with a solid wire, then the UPS is at risk of battery rupture/fire if the components fail inside especially with the newer plastic cabinet units.

The buzzing sound is due to modified square wave output. It's a normal behavior and it most likely will add moving stripes on a CRT monitor and noise into speakers.

[Anonymous user]

There wasn't a fuse with the old battery to battery connector. It was just a plain wire. I could hook up a fuse it necessary. What amp fuse would it need to be?

What does it mean if the square wave output is modified? What exactly has made it change? So I don't need to worry about it then? There is no speaker noise and I don't have a CRT monitor. I was just worried if it was a problem or not.

[BillP · Accepted solution]

It's coming from your computer's power supply - it isn't a fan of the step-approximated sine wave output of the UPS when on battery. Some power supplies do that. Honestly not sure if it would cause a problem, but I've known a couple of people who didn't like it or felt nervous about it, so they connected their computer to a Smart-UPS (pure sine wave) instead.

It's just a matter of how similar the power output is to regular electricity. Normally a sine wave (without distortion) is an even curve, but the UPS you have is more like stair steps following the wave. Check out the pictures from this article - namely the one at the bottom - that might help your understanding.

[voidstar_apc]

Here's a good [picture of a modified square|http://www.panelectron.hu/webshop/images/square_modified_sinewave.jpg].

I wouldn't worry about the buzzing if the computer and UPS are working normally.

[Anonymous user]

Thankyou for the picture.

I am also wondering how I can extend the running time of the UPS. I thought it would be better to not start a new thread when I only need one reply here.

In a previous thread I was told that the UPS needs 24v to run properly. Therefore the 2 batteries are wired in series to reach a total of 24v. I was also told that the connector at the back allows for more batteries to be connected to extend the runtime.

If I were to get my hands on another APC connector so I could actually use that connection at the back, how would I wire the battery up? I mean can you only have one battery connected to the back? Or could I have 2 batteries connected in parallel so that I'd have a whole lot more runtime?

Unfortunately all I have available to me are the cheap batteries available where I live in India. The original APC batteries would be very expensive and hard for me to get. These cheap ones don't really last very long even when they are fully charged. So I need to add one or 2 more to extend the runtime. Unlike in the rest of the world where a UPS would only act a little bit as a surge protector and pretty much never as an actual UPS, here the power goes off many times a day. Currently the power is cut for 4 hours a day, that's the best it's been in a long time.

Also, what wattage would the UPS be using when it is charging the batteries? I mean it is a 1 Kilowatt UPS, but it wouldn't use that much to charge the batteries would it? Does anyone know how much it would use?

Thanks

[BillP]

a) The BR1000 does not have a connector for extended run batteries, only the BR1500 in the Back-UPS family has that feature. Also, the 1500 model is designed to accept only one battery pack.

b) APC wouldn't be able to offer any instructions for wiring your own battery, though if you're having such poor luck with the cheap batteries you're using, maybe it would be worthwhile to get the more expensive ones? ?:|

c) The charger in the BR1000 is only 20w.

[Anonymous user]

I have the RS1000. It has a connection at the back. It fits the connector that is used to wire up the main batteries. Does the RS model have this feature?

20w? Wow, must take quite a long time to charge up the batteries fully?

[BillP]

RS is the family (Back-UPS RS), not the model. If you look on the unit (back or bottom usually), there will be a white sticker with barcodes on it. This will have the exact model and serial number. What do you have?

Yeah, the battery chargers aren't too beefy since, like you said, most of these units' implementations aren't for very frequent or extensive outages.

[Anonymous user]

Mine says BR1000-IN.

At the back of the UPS where the connector is, it says "BR24BP Battery Pack".
The connector is there and does work when batteries are plugged in. How can I use it?

[BillP]

Ah, sorry about that. I only really know the North American models well; the BR1000-IN does have that functionality, too.

In terms of using it, well... All I can really tell you is what you already seem to know. It's a 24v battery pack, though it is only designed to have one 24v pack connected, no more than that. Anything beyond that is using it at your own risk, and certainly not APC supported... Maybe someone else has had luck custom-fitting more than one?

Additionally, there are other models that can support more than one battery pack, so you may want to look into those options. Depending on how much capacity you need, you could check out the [SUA750XLI|http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=SUA750XLI] or [SUA1000XLI|http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=SUA1000XLI]. Different receptacles than the unit you have now, though I honestly don't know if any of those exact receptacles are available on Smart-UPS models...