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Installation has to be done professionally.
How could it be professional if the person doing it has no idea what he is doing and needs help on a forum? Clearly there are either not enough docs or not enough knowledge/expertise/experience to call it professional installation.
Not too long ago I witnessed how a screw up on UPS installation caused injuries to the crew so that first aiders had to attend and London Fibre Brigade showed up shortly after the fire alarm and full building evacuation, and this was with all procedures followed (on the DC side, can’t say about the contractor). Here - not so much.
And yes, low voltage.
@Clouvider
I perfectly get what you are saying but hey, a) @cociu is just the one asking for advice, not the one doing the electrical installation stuff and b) the one doing it, if I got that right, is a certified electrician.
Low voltage, high current. Doing something wrong on a ups loaded with a high amount of powerful batteries can cause you really disgusting burns, you should be careful if you dont know what are you doing - especially if you play with DC voltage and high current.
There is a reason why you can weld with high dc current easily
Well I can't speak for a big APC UPS, but this is exactly how my SANTAK UPS works. The UPS determines the battery configuration based on the voltage it can see.
It expects to be installed with Deep Cycle Lead Acid batteries, and so it knows pretty much what the voltages would be for a given state of charge.
Obviously. I have not said that the voltage of the battery bank corresponds to the AC output voltage. The AC output voltage should always be 230v, and with a perfect sign wave regardless of the batteries. The current supplied also should remain static.
My point was that for the purpose of monitoring the state of charge, and for charging, it is important to have the correct battery configuration.
In order to charge a 12v batter, you need to supply it with around 14v until the battery charge reaches around 13v. This multiples up, so a 20 battery array with a nominal voltage of 240v will require around 280v to charge. The UPS will stop charging once the array has reached the preset max voltage of 260v.
So if you put in 19 batteries, instead of 20, all those batteries would be OVER CHARGED. Likewise, if you put in 21 batteries, all the batteries would be undercharged. The former being incredibly dangerous and the latter would mean having very little in the way of actual usable capacity.
So in the case of my SANTAK, where the specifications call for either 16 or 20 batteries, this is important. The UPS must have a way of knowing what the battery configuration is. Unless you can specify this manually in an APC, I would be surprised if it was done in any other way.
As for putting things in parallel, that's great if you want to increase the storage capacity of the UPS. You could theoretically parallel out to infinity. But doubt that an 80kva UPS would take anything less than 240v battery bank.
If you tried to draw 80kw of power from a 12v source, you would need ENORMOUS cables to handle the current. It's just practical.
guys , i have not posted here to execute what the people is post , i have hope someone have the same model and have some more documentation. Any way in the wrost case i will wait ...
I'm out of here. Have a nice day - and may the polish (or italian? romanian? turkmenian?) dealer be merciful and send someone not in 5 but just in 2 months.
@randvegeta
Thanks. Just in case you are interested: I actually have designed and built my own (small office) ups. And I'm even still alive or so it seems to me. But maybe I was just lucky.
http://www.apc.com/shop/us/en/products/MGE-Galaxy-5000-Battery-Cabinet-480V/P-G5TBAT
This is pretty clear to me that you're supposed to use 40 batteries in series.
I don't know what you're trying to say here. You saying that the voltage of my battery bank is not important? Or that my battery bank is not actually in series?
Or are you saying that APC is definitely 12v in parallel and not in series?
Since I don't use APC UPSs, I don't know what the configuration is actually like, but I know for a fact that my SANTAK is as I described as I setup the battery banks myself (and nearly killed myself in the process!). Yeah I'm done handling with DC 240v that can deliver a thousand amps all at once... Scared the bejesus out of me...
The issue is cleared, funnily by documents found on the link provided.
The batteries as well as the cabinets (if more than 1 is used) are 12 V and in parallel - just as I said. (ref: http://www.apc.com/salestools/BYSN-APV95X/BYSN-APV95X_R0_EN.pdf).
So, neither the cabinets nor the batteries are in series which also means that the "x batteries times 12V must be = 400 V" (or 480 or whatever) equation suggested by some here is nonsense - just as I said.
Both are in parallel (as I said and as can be seen in a.m. ref. as well as in http://www.apc.com/salestools/NKRY-7XWBNT/NKRY-7XWBNT_R3_EN.pdf)
Also, the document clearly and expressly states that customer (as opposed to "apc" or "auth. dealer") is supposed to do the wiring.
Thank you, @APC for confirming what I said all along.
For the life of me I cant find any references to battery voltage in this doc.
If you zoom in, one can see that such an additional cabinet is supposed to hold 36 batteries in series:
obviously they are named B1-B18 and B19-B36 on that schematic.
my apologies @randvegeta, I would not have believed before seeing that they really do such a serial setup...
but as a conclusion, I'd say most likely the normal UPS needs the same amount of batteries then, to reach the same voltage.
So not 12v paralleled out for APC.
36 is odd though...432v?
as said before I wouldn't count on much math here for the voltage thing at all, I still stand by that point ;-)
yet it might make sense to have a voltage near the AC in- and output to keep losses on switching/regulating low and maybe gain a higher efficiency. but that's above my paygrade after all ...
I would say that any voltage goes, as long as it's above the voltage needed to generate the AC so no up-converting is required, and all it takes is a big PWM driver to deliver the power into a nice sine.
Agreed it is not strictly necessary for the voltages to be the same. And to be fair, voltage regulation can normally be achieved fairly efficiently. But pulling 80kw of power output from a 12v supply vs 400v supply makes a huge difference to current. If using a similar voltage, you can use the same gauge of wiring :-).
Just a bit of simple maths here:
To pull 80kw of power from 400v, that's about 200amps. From 12v, that's 6,666amps. Think of the gauging on those wires!
I've looked again and this time closely and I stand corrected.
Yes, the batteries are indeed in series and the voltage is 432 V. This is quite strange and indeed seriously dangerous, but they seem to have done it because that's about the only reasonable way to deal with type of battery (VRLA). The reason, though is not an "x times 12 V batteries = output Voltage" equation but simply because that happens to be the number of batteries that fit into a halfway standard rack-size battery cabinet. (output voltage is either 400 V or 480 V).
Explanation: Those VRLA batteries have certain desirable properties (i.a. being cheap) but also the very undesirable property to be picky about loading cycles and voltage and about "low" voltage. The useful range per cell is just about half a volt (and a 12 V battery consists of multiple cells). So, to get some reasonable VA*time out of those thingies they must "blow up" the useful window by connecting them serially up to 432 V.
But the cabinets are in parallel (if multiple ones are used) and the "x times 12 V = Vout" equation was wrong anyway (or just a coincidence if one wants to see it that way).
P.S. Yes those are, of course fat wires. And No, it's not 80 kW, it's 72. The 80 is kVA (not the same thing). A classical marketing trick in the ups business.
>
so let's agree then, that the answer to @cociu question is
4236 ?! ;-)Sure. While I like the hitchhikers guide through the galaxy my reason to like 42 is just because it's my preferred prime number. So, 36 is no earth shattering problem for me (unlike for the hitchhikers who must now reformulate "42 is the answer to all questions but one")
I was just using it as an example. 80kw or 72kw... either way.. that's a lot of power, and to pull that much power from 12v or 480v would require vastly different types of cables :-).
So let me get this straight. OP comes in and asks weather or not he needs 30 or 40 batteries and we've decided on 36?
Is it just me or does the APC UPS system seem overly complicated?
We've got dozens of SANTAK UPS deployed in our DCs in HK and LT and honestly those are damn simple. There is a positive and negative terminal for the battery bank, expecting either 192 or 240 nominal voltage. There is no special battery cabinet, we custom built our own battery enclosure, using readily available 12v lead acid deep cycle batteries. We hooked up the batteries and series, connect that to the UPS at the positive and negative terminals, and bam! Bob's your uncle. All is well. To increase capacity, just hook up each battery enclosure in parallel and the UPS capacity grows proportionally.
To be fair, our UPS are not 80kva, nor are they 3P. So perhaps they are a tad simpler. Still..
Can't get much more LET than that.
@randvegeta listen to the man he knows what he is talking about.
The batteries are storing electrical charge through chemical processes, they are to be considered charge buckets, it has nothing to do with actual voltage, plenty UPSes have 12 V battery for 240 V AC output, I even saw 6v ones...
A serious UPS, not a soho one, has complicated electrical bridges and regulators which can adapt to almost any situation, such as short-circuit in one of the batteries, overheating, some even detect gases and smoke. If you put them + to - and make a long chain any battery blowing up will break the circuit making the UPS output 0 power AND the higher potential added up will wear them more easily.
They are normally designed to be wired in parallel, a battery is already made up of a number of units serialized in the plastic chassis, each one of them can be a SPoF, you absolutely do not want that. I suggest you reconsider whatever system you are using, it is a ticking bomb and I am not talking about leaving you flat when power really fails, but a real bomb with smoke, toxic and/or explosive gas and fire.
Huh? Did you read this part:
or this:
I do not say that the battery voltage must equal or be similar to the output AC voltage. If you read my responses, I say nothing of the sort.
I made 2 points regarding battery voltage. 1.) That it must be known in order to determine the correct SOC and the charging voltage. And 2.) That lower voltage would require much larger gauge wires for high output power.
It's all well and good getting a 12v battery to output 240v, but not if you're trying to suck 10kw of power of it.
Am I wrong?
They are normally designed to be wired in parallel, a battery is already made up of a number of units serialized in the plastic chassis, each one of them can be a SPoF, you absolutely do not want that.
exactly what I thought, I just couldn't put it that straight ;-)
obviously APC doesn't care about all of that and decided completly against. for me expecially going for that despite the single point of failure with one battery dying isn't easy to grab. it's like running raid0 and if you want redundancy you are forced to use an additional cabinet which of course is wired in parallel, so you achive something like raid 0+1 ? hmm...
The 10-100 kw through a single wire at 12V is not really going to happen in a big UPS.
The idea was that they are wired, bridged, whatever the term is in English internally to give the maximum of redundancy and control with a number of "units" made up of a number of batteries. It can connect and disconnect them to charge and in case abnormal situations are detected, etc. A big UPS is essentially a "battery" of UPSes, an intelligent storage unit, not a dumb terminal where it simply expects a certain voltage and blinks a red led if it does not get what it wants.
A big (read, like a couple of racks) UPS has built-in redundancy and is somewhat fault-tolerant, you also build a system with them in a DC, you wire them at every floor, not only to the racks switches to power racks and the main line, but also among themselves and to a control panel or more, so if one floor loses power, they cooperate to keep it up for as long as possible, at times more than a day in a large enough DC.
I am sorry, my tone was a bit harsh, however, i imagined you soldering wires to terminals from one battery to another, holding them together with adhesive tape and got really worried. In general, this work must be done by the UPS producer/supplier which should also offer at least a wiring scheme and a necessary of units and spares for the initial run. Electrical stuff, especially if involving high capacity batteries put together in a small space is to be left to the specialists and manufacturers, they know best what are the safety limits of their products. At times they already pushed them to dangerously close to or even above the safety limits to squeeze more power and life with as little cost as possible.
Yes and no. You are right on paper but you are wrong in that the diameter of those cables isn't that important. They are FAT anyway and the diameter does not increase proportionally.
Btw. and as you don't let go: The real main reason for apc to do it that way is simple profit greed. It's simply cheaper. One could perfectly well - and does in good upss - work with much lower (and less dangerous!) voltages but that's like with everything nowadays: Save 2%% by doing something the cheap way or by using cheaper materials is the sad motto.
Efficiency, for example (with which apc brags) is simpler to get when input and output voltages are closer (creating 400 or 480 V output is cheaper to create from 432 V than from 12 or 24 V).
Another point is, of course, that in an industrial environment ups manufacturers get away with much more. With normal office upss they'd quickly have by far more trouble than they can digest if they played high voltage tricks. There the upss are almost always 6 or 12 V based.
And yes I have seen plenty 12 or 24 V battery banks based upss in good data centers.
"single" underlined. What's usually done with good upss (incl up to multiple 100 kVA) is to have multiple banks. So, on a large shelf there are 2 rows per level with each, say, 20 accus/batteries ("accu" is the correct term but "battery" is the commonly used one) in parallel. Then there are 4 or 5 levels of those which might be in series (4 * 12 is not uncommon, particularly a telco equipment mainly ran on 48 VDC). And then multiple full shelfs as described which again are parallel both for resilience and for higher capacity. Plus: Adding capacity is easy - simply add new shelfs.
And again, wires or wire size is not the problem. For one it doesn't grow linear proportionally plus, more importantly in large installations one often doesn't use wires at all but copper bars (sometimes, depending on voltage) not even insulated which is no problem with, say, 24 V.
It is battery because it generally has a battery of accu units inside.
At times other materials too, as copper is expensive and DC does not have a similar problem with AC with frequency in steel.
Yes, that is what i meant, an UPS has a number of these and an n+1 at least redundancy, it can connect and disconnect them as needed for charging and discharging cycles or in full load during an outage.
The official difference is this: An accu is recharable, a battery is not.
Nope, not steel; has diverse problems. But aluminium is sometimes used, Very good conductivity (not as good as copper but still quite good) but typically not in upss. Reason (I assume): bridging time is a very major criteria for upss and they want it to be as long as possible, hence they use the best material to keep wire losses as low as any possible. Plus, haha: Typically installation (and installation material) is on the customer; he pays for that so the manufacturers have no reason anyway to save money.
Yes. A quite typical layout I saw is a couple of long (5 m or so) double row shelfs with 4 levels with each 2 accu rows and the shelf rows about 2 feet (60 cm) apart so that each accu can be reached/installed/changed/replaced.
Having planned properly this also allows to add shelfs as your DC/demand/need grows. Simple and cheap and versatile.
P.S. Those professional good quality upss of course also allow to easily add capacity to the ups itself, e.g. in 25 kVA increments.
There are "rechargeable batteries", but this is not what i mean. A lead cell produces about 2 volts, a 12 v battery is made of 6 cells arranged in a battery in a serial connection. The car battery is made of 6 lead accumulator cells. It may be different in English, though.