Is home UPS worth it?

digitalp said:
I use a Liebert gtx2 6000RT230 UPS that uses a Pack of 20 CSB HR1221WF2. Are the batteries suitable to be used for prolong periods?

See specs here: http://www.emersonnetworkpower.com/en-ASIA/Products/ACPower/RackmountUPS/Documents/Liebert%20GXT2%20500VA%20to%2010%20kVA%20-%2050Hz%20-%20Users%20Manual%20-%206000RT230.pdf
Click to expand...
Thank you. :)

Did you have to import it?
The UPS looks like it is better suited for a server environment and not for home use. It will probably be way out of the price range I’m looking at.
 
digitalp said:
I salvaged it from work and replaced the batteries. I use it to power 2 TVs, a server, 2 fire tv stbs and my sound system.
Click to expand...
You are very fortunate to have found it. I am however looking for something that would be wired into the DB and not a standalone unit.
 
Anybody contemplating putting one of these systems together yourself PLEASE just be aware of the level of current you're generating and make sure you have sufficient gauge cabling.

Although this may be obvious to many, current (not voltage) is what causes resistance which heats up wire. This is usually not an issue on a household circuit's 230V AC since the higher voltage means lower amperage. This is something that the average Joe doing their own thing often doesn't think about.

On the DC side the lower battery voltages mean much higher current for the same wattage.

Divide the inverter wattage by the input voltage from your batteries and you'll get an *idea* of the amps - e.g. a 2000W inverter with a 24V battery config means that there is simplistically approx 84 amps going over those cables at max draw. Make it a 5000W inverter at the same voltage and now you're pushing over 200 amps! If you try to wire this up with normal household wiring, you will have a disaster. (These figures are simplistic as there are other factors but this is a rough idea).

The danger is you set it all up, runs fine with a light load when you test, but then add load later and if the wiring on the input side is not up to spec you will have a cable meltdown - possibly even a fire and most probably ruining your batteries and inverter.

Opt for safer higher voltage DC configurations (series more than parallel) and make double sure your cabling is rated to handle it.
 
garp said:
Opt for safer higher voltage DC configurations (series more than parallel) and make double sure your cabling is rated to handle it.
Click to expand...

+10000 - rather OVER SPEC, than under spec. There's a reason why DECENT battery cable (100A cable) is R50+ per meter... For your safety...

The same can be said in terms of terminating cables too... Lugs, lugs, and more lugs... Crimpers, Solder, etc.
 
savage said:
+10000 - rather OVER SPEC, than under spec. There's a reason why DECENT battery cable (100A cable) is R50+ per meter... For your safety...

The same can be said in terms of terminating cables too... Lugs, lugs, and more lugs... Crimpers, Solder, etc.
Click to expand...

Not sure what's your opinion on this but check this thick mofo cables we used to hookup a 3kw 24v system with 6 x 200ah batteries ...
IMG-20150309-WA0002.jpg
 
The_Traveller said:
Not sure what's your opinion on this but check this thick mofo cables we used to hookup a 3kw 24v system with 6 x 200ah batteries ...
Click to expand...

Difficult to guess, but those look like 100/110A cables yes. Outer diameter of the cable (incl. insulation) is about 22mm or so... Those are the right toys for the batteries yes.
 
Nefertiti said:
I am stickying this as I would be interested in a similar solution.

I currently gave an intellipower (something like this : http://www.maidenelectronics.co.za/ProductInfo.aspx?productid=INT4) but I want to add something to the db board.
Click to expand...
I’ve also looked at the plug and play units. The disadvantage is they have to be close to the equipment you want to use and they do not produce a sine wave power output.
Connecting the inverter to your DB enables you to use your homes existing wires and it will keep everything neat and tidy.
 
Very good advice regarding the cables. Thank you garp and savage. :)
Is the cost of the cable the reason why the inverter and batteries should be close to each other?
 
LaraC said:
Is the cost of the cable the reason why the inverter and batteries should be close to each other?
Click to expand...

Not really no. Low voltage / high amperage is the problem. Add to that, the fact that it is DC voltage as well. High Voltage / Low Amperage is generally not a issue in terms of voltage drops.
 
savage said:
Difficult to guess, but those look like 100/110A cables yes. Outer diameter of the cable (incl. insulation) is about 22mm or so... Those are the right toys for the batteries yes.
Click to expand...

You sure ? The red cable is 25mm ... 20150530_172235.jpg
 
BigAl-sa said:
That red cable certainly doesn't look like 25mm. 25mm is 1" in the old language, roughly the length of a man's thumb from joint to tip.
Click to expand...
Yip doesn't look like it but it is . Unless you saying the printed/inkjet coded digits on the cable 2 and 5 with the mm after it , then 2 again doesn't stand for 25mm2 ?
 
Last edited:
BigAl-sa said:
That red cable certainly doesn't look like 25mm. 25mm is 1" in the old language, roughly the length of a man's thumb from joint to tip.
Click to expand...

25 mm^2 - square mm

So copper diameter is 25 / (3.14^2) * 2 = about 5 mm

Steve
 
elbow said:
25 mm^2 - square mm

So copper diameter is 25 / (3.14^2) * 2 = about 5 mm

Steve
Click to expand...

Close. The formula for area is A = pi * r^2. So to get back from the area to the radius would be sqrt(A / pi).

r = sqrt(25 / pi) = 2.82mm
And the diameter is then 5.64mm
 
You must log in or register to reply here.
Back
Top
Sign up to the MyBroadband newsletter
X