cable thickness, feed the house, UPS APC, Panels - lots of questions.

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N00bPwr

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Jul 18, 2017
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let me try one more time..


Can i run 50 amps through 5x2.5mm2 solid copper wire, the wire is just like this:

image_cvibpp.jpg

all i can find is if 2 out of the 5 leads is used, then 25amp is ok. or is the use of 16mm2 a betterchoice

I have a APC 3000 RT, the model before the 3000 XL, now can i feed some of the power back to the house, not much is needed, 300-500watt
 
Soooo, uhh, what's your questions? All I see is a list of statements of what you've done so far.
 
Hmm First of all let your electrician set the AC part up. Especially to make sure you have adequat wiring... So that was the legal line. Lets talk a litle bit about it.

First of all above wire you found is for 3phase AC system. Is it 3phase or 1 phase?
I have no clue where you got those 50A from? 3kW at 230W is 13A and at 120V thats 26A. If we talk about 3phase 3kW then the current is even smaller per wire itself

2.5mm2 Is generally said to do 16A in sweden for most builds. But this does of course depends on the length of the wire and if its in the air or in the wall. So yes your 2.5mm2 will easily cary 3kW over x distance.

Before hooking a wire like that in you need to make sure to have proper breakers before. In general 16A would be a good choice.
 
since i have about 100 meters of 5x2.5mm2 solid copper wire which i did intent so use it from my batterys and to my inverter, hence the term 50A, since my APC back UPS is rated for 2700watts, and the 50amp should be the draw amp from my battery's

But i may have fallen into a dark hole with the APC, is it the same unit as AveRage Joe's but it is a 240 volt unit, and therefor the 2 internal battery packs is rated at 8x12v = 96volt each.
 
Above cable is for AC. You can potentially tie together and get 2*5mm2 but its not enough for 100Meter....

Dont transfer that amount of current on that cable. Per thread max should be somewhere around 16A and that is with several % of loss. Not sure of it exactly but can calculate tomorrow if needed.

If you going to transfer AC 230V 2300W then its ok but thats NOT 50A.
 
N00bPwr said:
But i may have fallen into a dark hole with the APC, is it the same unit as AveRage Joe's but it is a 240 volt unit, and therefor the 2 internal battery packs is rated at 8x12v = 96volt each.
Click to expand...

Are you sure they are all in series, and not 4 pairs in series?
 
Most smaller APC UPS systems are 24 or 48V. Not many of the ones below 3000VA is above 48V.
 
N00bPwr said:
Can i run 50 amps through 5x2.5mm2 solid copper wire, the wire is just like this:
Click to expand...

2.5mm2 single strand can handle app. 20A.
So if you tie together all strands then yes the cable can handle 50A in *one* directon.

Since the strands are not wound, but isolated they will not balance well, but assuming they have app. the same resistance (you coul d meassure to verify), then if we are talking DC and you use 50m for positive lead and 50m for negative lead then you get an impedance of the full length of 100 m. with a total voltage drop of roundtrip of:

18.1 Ohm/km*mm2 =>
Rtot = 18.1 Ohm/km*mm2 * 0.1km / 12.5mm2 = 0.144 Ohms

Pulling 50A would then give a voltage drop of 50A * 0.144Ohm = 7.24Volt!
=> Powerloss = U*I = R*I^2 = 360Watt
 
my UPS are the SURTD3000XLI 3U rackmont, and from what i can find online it uses the RBC44 battery units.
and from this page:
https://www.techbatterysolutions.com/APC-RBC44-Battery-Assembly-Guide-s/2796.htm

Quote: "After the batteries have been replaced inside the RBC44 cartridge, its time to grad your diagram and re-wire the batteries. Once you are finished with the re-wiring, you can double check that it is correct by checking the voltage of the pack through the plug on the front of the battery pack - you should be seeing something around 100-104 volts"

and i did find a youtube video :
where you can se the battery setup.

I have a smaller APC RT3000 that is 2U, which use a 48watt battery pack according to the battery cartridge.. i may use this one if i can not make the 3U unit to work, the total need of AC power aint going to be that big.

The 5strand/5 wire cobber wire i have about 100 meters off - just for the info.
from the charge controler to the batterypack there will be max 5-6meters or less for the positive side and the negative side.
 
Ahhh, I see what you mean about the voltage. That's because of how many they use:
Tools You Will Need For the RBC44 Installation
......
16 - 12V 5AH SLA Batteries (each RBC44 pack has two banks of 8 batteries)
Click to expand...

Now that makes sense. So they are 8s. Maybe that's what the "I" is for in the model number, denoting a larger voltage on the battery side. Or the "D". Either way, it definitely shows it's a larger unit.
If you're only going 5-6m, that should be just fine. However, it would be better to use a single larger wire instead of trying to bond two of those together in what you've shown. It will work with what you have, but as Hannsing said, you could have slight differences in the resistance between the wires, which would cause one to heat up more than the other.
Now, if you were going to use those as bus wires and strip them and twist them, perfect.
 
it is and will only a temp setup - just to learn more about it before i make a decision to what route to go.

I did test my SURT3000 RT rack mount 2unit - that is a 48v unit with 4 old lead acid battery's and it works, but there is no fun i 48v and 2-3amp :)
i have 8x12v 120amp GEL batterys on the way, but putting them i a 96v@120amp setup and finding a charge controler to fit the 96v might be a problem, or finding a inverter for that matter.

Might look for a MPP solar 10K unit, hooking the GEL's to that in a 48V config, and add 2000-3000watt of panels more to my 6000watt setup now, to a total off 8000-9000PV total, only problem is the 2500 dollar the MPP 10K is..
But i really do appreciate all the advice given here. thnx.
 
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