Here are a few extra pictures.

Doesn't look like anything special, just 8 battery's and a Pbc with fuseses for the most part. I bet you this could be easy to change over to 48v just some wiring and changing out that control board.

Transformers don't work on DC, only AC - you could convert the DC to AC, transform it, and change it back to DC, but that would obviously be losing sight of the point of the UPS itself, and would be way too inefficient, time consuming and costly. (I know you aren't insisting on them, just sayin'.)

These things are passive (the board is mostly for ease of installation - point to point wiring means manual assembly and can have mistakes) so will be easy to change.

if this is 24v then it's 2s4p and you can literally just change the wiring to be 4s2p. You might need to buy a small amount of wire and some crimp connectors to do this as the wiring can be different lengths or can be cut up differently for series vs parallel use. Fuses are probably fine because you're looking for more voltage, not more current, and the 24v model is probably for a lower power UPS than the 48v one would be for, meaning you'll be capable of pulling more than half of the fuse rating. (What I mean there is that if you were pulling the same total power, but at twice the voltage, you would have half the current via Ohm's Law V=IR - if you're pulling more power and you have twice the voltage, you do NOT want to halve the fuse ratings - but you can take the power of the UPS and divide that by the battery voltage for an approximate max load.)

One thing you should verify, though, is how the main connector is wired. Is it wired up for balanced charging i.e. number of wires = 2+(number of batteries in series i.e. 2 or 4) (edited to make that 2+, because one of them is a mains earth which I see in your photo and which makes sense logically), or is it just +/- (possibly using multiple connectors in parallel if the connector has more than 2 contacts, like my Liebert GXT2 did; I think that had 5 contacts for the EBM connector)

Edit 500000: D'oh, the rectangular connector is obviously for EBM chaining, meaning either it has 2 + and 2 - in parallel (for increased current) or it does seem to be capable of balanced charging... You may need to open the UPS and check how the connector is wired if you can't find a datasheet showing it... You would likely be able to use a DMM and check continuity between each wire of the EBM connector and each battery. If you find that each battery terminal goes to a separate wire, you'll need to rewire that on the EBM side as well. If this is not the case, then maybe it's just two parallel connections, and the connector won't need to be rewired.

I've probably been a bit confusing here as I sort of started writing this before finishing inspecting your photos. Feel free to ask for clarification.

I completely forgot about transformers not working the same way in dc. So basically it just needed rewired.

Jade Falcon wrote:

I completely forgot about transformers not working the same way in dc. So basically it just needed rewired.

You may have noticed after you submitted that, but I edited my post a few times. Make sure you've read what I had to say about the connector itself. It could either just have 2 parallel runs of wire for increased current capacity, or it might need to be rewired on the EBM side if it's actually balanced. Heck, you can check this even easier than what I said in the last post - just check the 2 + and the 2 - for continuity on the EBM itself while it is disconnected and while the batteries are also disconnected. Probably the easiest way to check. If they have continuity with the batteries disconnected, you do not need to rewire the connector.

It's tough to tell because 2 parallel runs of wire for current is very common, but your EBM also happens to have 2 battery series groups. So it could mean either thing.

Will check the continuity.
I know the cable has 2 + pins 2 - pins and one earth. Both + pins are 24v.

Jade Falcon wrote:

Will check the continuity.
I know the cable has 2 + pins 2 - pins and one earth. Both + pins are 24v.

You are good to go, then. If it were a balanced setup, each would have 12v, and the UPS would have used them in series for 24v. If that has 24v for each for a 24v system, they are parallel.

Just need to rewire the batteries themselves and you'll be good. To go the extra step, change the fuses to what they used in the 48v model - apparently the EBM (and maybe the UPS itself) show the max current on the back but your EBM of course shows it for the 24v model. The fuses on there will probably be fine though. If you do change them, use ratios to size them - your EBM shows a max current rating for it at default configuration, and you can see what those fuses are rated (PCB seems to say 30A) - you can make a ratio out of that and then multiply that by the max current rating for the 48v model EBM.

Edit to elaborate: When I talk about calculating the fuse with a ratio, because I'm talking about a current rating for the EBM and a current rating for the fuse, there is no need to invoke Ohm's Law or do anything to compensate for the voltage differences. Not sure if anyone would have questioned this, just making it clear in case it helps someone understand that better.

Ok just checked the continuity with the battery's removed. There is no continuity between the negative and positive pins. But continuity between the two positive pins. There is also continuity between the two negative pins.

Edit.
continuity Is the same with the battery's conceited.

Jade Falcon wrote:

Ok just checked the continuity with the battery's removed. There is no continuity between the negative and positive pins. But continuity between the two positive pins. There is also continuity between the two negative pins.

Good. That result verifies that they are in parallel and it thus agrees with your prior 24v measurement.

Thanks for the advice. I originally thought that it only needed rewriting. And maybe different fuses. But I don't have enough experience with electrical work to just go at it.

Also what about the two blue capacitors? There labeled 103z/250vAC

they go to ground so I suppose they are probably basically Y capacitors for EMI suppression

but in any case they've got a high enough rating, no problem

I fugued they be fine.
Thank for your help!

You're welcome. Let us know if you need any help with the actual rewiring also. If you need to buy any wire you should probably go 8 gauge though 10 gauge may work if you don't end up needing to increase the fuse size. I can't really tell the gauges very well from the photos.

Edit: By the way, it's better to not check continuity across things that have voltage. In this case it wouldn't have been a big deal because the EBM isn't connected, so there is no current flowing out of it, and the only "load" is a "local current loop" created by the meter and the 2 positive wires going to the 2 different terminals. Because the current flow will be low, the voltage difference between the two terminals will be very low, under a millivolt most likely, so your meter is safe. However I mention this more as a general warning because if you measured something with a higher voltage difference and drove significant voltage in your meter, you may blow your meter. A good meter would be protected to a certain degree but best not to risk it. A cheap meter might have very little protection.

I'm useing a ideal 61-492 meter. Should be more then safe.

I got the ebm rewired. Seems to be fine so far. But I have yet to put it under a load.