Dell 2700w j728n 3kVa UPS not starting

[nle]

Re: Dell 2700w j728n 3kVa UPS not starting

No, not yet. I did get my hands on a non-smart charger, but the batteries are dead. I am pretty sure new batteries will solve it, and I will buy new at some point and report back here.

Not sure when though, I don’t really need the UPS, it’s just a nice to have.

[Ateece]

Re: Dell 2700w j728n 3kVa UPS not starting

Did you manage to revive it? I have the same ups in the same state. Batteries are definitely dud but from the manual I believe this should power up even with no batteries. Wondered how u got on.

Good point. I'll see if I can get my hands on an old school used one for cheap (I'm in Norway, not Sweden btw. )

If I need to get a new one, do you know if this would do the trick? It's the only "old school" new charger I've found:
https://www.biltema.no/bil---mc/bilb...8-a-2000030702

[Per Hansson]

Re: Dell 2700w j728n 3kVa UPS not starting

That looks like it would be based on an old iron transformer since it weights 2.3KG.
So I'd say that is a proper charger

[nle]

Re: Dell 2700w j728n 3kVa UPS not starting

Good point. I'll see if I can get my hands on an old school used one for cheap (I'm in Norway, not Sweden btw. )

If I need to get a new one, do you know if this would do the trick? It's the only "old school" new charger I've found:
https://www.biltema.no/bil---mc/bilb...8-a-2000030702

[Per Hansson]

Re: Dell 2700w j728n 3kVa UPS not starting

I do have a smart 12V 8A (The batteries are 12V 8.5 Ah) charger that I tried on a couple of the batteries. That is throwing an F1 error message right after it tries to assess the battery.

F1 error could be: "Clamps are not secured", "Short circuited" or "reverse polarity". But none of those should be the issue.

"Smart charger" well that is probably the definition of the word oxymoron if you look it up in a dictionary!
If you have a "stupid" charger then try that, if not it might be worth getting one.
(You know the old kind with a big chunky transformer inside )

Edit, something like this:
https://www.tradera.com/item/343575/...l-veteranbilen
https://www.tradera.com/item/343575/...-6-12-v-22-amp

[nle]

Re: Dell 2700w j728n 3kVa UPS not starting

Cruddy? Not sure what you are looking at, maybe the plastic on the connection has a bit of a tint? Anyhow they are more or less pristine. No bad connections there.

[CapLeaker]

Re: Dell 2700w j728n 3kVa UPS not starting

Did the batteries looked that cruddy 2 years ago? Just sayin... lots a green... That can't be making good connection.

[nle]

Re: Dell 2700w j728n 3kVa UPS not starting

Thanks for the input.

@Per Hansson
I do have a smart 12V 8A (The batteries are 12V 8.5 Ah) charger that I tried on a couple of the batteries. That is throwing an F1 error message right after it tries to assess the battery.

F1 error could be: "Clamps are not secured", "Short circuited" or "reverse polarity". But none of those should be the issue.

My guess is that the batteries are too low for it to do anything, but I'm a bit out of my league on this stuff.

@Dannyx
Thanks for the suggestion, but I don't have a variac, and I think that's waaay out of my comfort zone.

[Dannyx]

Re: Dell 2700w j728n 3kVa UPS not starting

One way of simulating UPS packs I thought of at one point, though this is both dangerous and possibly expensive if you don't have one, is to use a variac with a bridge rectifier. Of course, you wouldn't touch anything or plug the unit into mains at the same time, since it's not isolated and even if it were, I'm not sure what would happen if the UPS tries to push current into the variac to try and charge the "batteries". It should at least give you an idea of whether it runs on batteries or not. Ideally, I'd also use an isolation transformer to make it reasonably safer, though it would still not allow you to feed mains into it for the same reason.

I own a 500va variac myself, but haven't actually been brave enough to try this. One other thing it may not like is the noise on the DC leads, since that DC ain't gonna be the cleanest out there...

[Per Hansson]

Re: Dell 2700w j728n 3kVa UPS not starting

Anything that simulates such a large battery voltage is going to be prohibitively expensive.
Have you actually tried to charge each battery separately on a good charger and see what happens?
Because the whole pack will of course not work if one cell is dead...

[nle]

Re: Dell 2700w j728n 3kVa UPS not starting

I just checked, and all batteries are connected in series – totaling 8 x 12V = 96V. I attached a photo for reference.

Is there any other easyish way to test to see if it will turn on, without spending money on 8 batteries?

[CapLeaker]

Re: Dell 2700w j728n 3kVa UPS not starting

Nope, because the batteries aren’t all in parallel. I am thinking it runs at 48V not on 12V.

[nle]

Re: Dell 2700w j728n 3kVa UPS not starting

And I'm back after two years. I finally had time to have quick look just to confirm that the batteries are all dead. And they are. Not surprising after two additional years just sitting there.

Anyhow, I just thought of something. Do you think it will be possible to hook the UPS up with just one battery for testing purposes?

That way I can get away with buying one battery, and if it works I can buy the rest.

[Dannyx]

Re: Dell 2700w j728n 3kVa UPS not starting

Probably a faulty cap somewhere that died overtime, even with the unit not in use....just my two-cents at this time....

[nle]

Re: Dell 2700w j728n 3kVa UPS not starting

I forgot to mention that I did try that – unplugged the battery connection and tried to power it on, but it did not work.

Will make a thread with more details as soon as I have the time.

[Dannyx]

Re: Dell 2700w j728n 3kVa UPS not starting

Try disconnecting the batteries and power it on without them. If not, it's troubleshooting time, so you may want to start your own thread and leave a link to it here as well since I'd be glad to hear more - at least I'd have a known working one somewhere out there in the world, for comparison if I ever get my hands on mine again

[nle]

Re: Dell 2700w j728n 3kVa UPS not starting

Thanks for the fast reply!

Not sure if you want me to keep posting here, or make a new thread? This forum seems like a good place to get input on how to get this working?

(I just posted below, and I can edit/move it to a new thread if you would like that).

I can't find any reference regarding powering up without batteries, only that it's possible to power on with only batteries (see below).

Starting the UPS on Battery
NOTE: Before using this feature, the UPS must have been powered by utility power with output enabled at least once.
NOTE: Utility power cannot be present at startup.

To start the UPS on battery:
1. Press the button on the UPS front panel until the UPS beeps.
- The UPS front panel display illuminates, and the UPS begins the startup sequence.
- The UPS cycles through Standby mode to Battery mode. The Battery mode icon displays on
- the UPS status summary screen. The UPS supplies power to your equipment.
NOTE: The UPS does not assume the load if you press the button less than three seconds.

2. Press the button to check for active alarms or notices.
Ignore the “UPS on Battery” notice and notices that indicate missing utility power. Resolve other active alarms before continuing. See “Troubleshooting” on page 69. After correcting the alarms, restart if necessary.
You can prevent a battery start (requiring utility power at the next startup) by simultaneously pressing the and buttons for three seconds. Battery start can be disabled. See the Start on Battery setting on page 47.

This UPS worked fine the last time I powered it on (two-three years ago), and have just been sitting at the same spot until we moved a few months ago when (and I finally got a place – and big enough fuse – to run it properly).

So I'm not sure what could have happened to it, except something during the transport and/or batteries? Afaik. it was pretty "well placed" during transport – and it feels like it's built like a brick (and heavy like one too).

As I said, I'm hoping it's the batteries, but I would like to confirm it some way (without buying new ones just to find out it did not work).

On a side note, I did try to measure the voltage from the wires that comes out from the UPS and plug into the batteries, and to my surprise, I got 25,4V (it was not plugged in). Is that normal?

(and I'm way over my head on this one, not really sure what to do)

[Dannyx]

Re: Dell 2700w j728n 3kVa UPS not starting

I didn't come across a fully functional one to confirm, but I know two things:

1) this one DID fire up fine without the batteries, even though it exploded as described later in the discussion when I tried it WITH the batteries on it.

2) the manual talks about an option you can change in the menus (which you probably can't access) which sets if you want it to allow it to turn on without batteries, which by default is on, meaning it SHOULD turn on without batteries indeed...try disconnecting them entirely, instead of trying it with dead batteries on it. Also have a look through the manual in case I'm wrong on this last bit.

[nle]

Re: Dell 2700w j728n 3kVa UPS not starting

Hi, bumping this.

Do you know if this model turns on without (or with faulty/discharged) batteries?

I have the Dell UPS 2700R that have been sitting for a couple of years. I only got 34,8V from the batteries (it's 8, so should be 96V), and it will not turn on at all.

So I'm contemplating buying new batteries, but I thought this model turned on regardless (as long as it has landline power), so I don't want to pay ~300USD for nothing. I'm hoping I'm wrong.

[Dannyx]

Re: Dell 2700w j728n 3kVa UPS not starting

Another idea that came to me is that I ran the test with those "probe wires" still attached to the riser with the SG252 and although I covered their ends with electrical tape, maybe it caused some interference on those output pins enough to cause the FETs to latch on...just another theory as to why they blew in the first place...

Today I discovered the input fuse on the charger module also blew, but the major components check out fine still, so I don't know what happened there...