How can I use a UPS?

[stumpfield]

A friend working at an computing facility told me I could have a couple of 18KVA UPS that they need to get rid of. Each weights 1300 lbs.
Input 208/240VAC.
Output: 240/208/120VAC.
Obviously, I have no plan to use them as UPS for computers. Any possibility I can use them in an off-grid home? Is it worthwhile to charge them with the generator and use as battery/inverter? Thanks for your comment.

 

[techman]

generally UPS's of this type are not designed or optimized for efficiency. They also are usually not rated for 24/7 operation. As a result, it will generate the rated output, but will be a battery hog.

You could do some research at the manufacturer, but you may be better to buy yourself a mainframe so you will have something to protect.

paul

 

[BB_TX]

Generally a UPS is there to provide short term emergency power in the event of failure of line power so that connected equipment can be shut down in a safe controlled manner. Some equipment does not like an immediate shutdown due to loss of power. The duration of that emergency power may be a few minutes to a few hours depending on the rating of the UPS and the load being placed on it.

 

[schmism]

depends on the type of UPS.

most UPS's of that size are not just huge inverters that act as the go between the batteryes and the grid but also power conditioners. the big ones like that usually capable of both correcting frequency varrations as well as voltage.

Ones of that size are usually rated for contious 24/7 use as up time is only limited to the battery stoarge size vs load. Some systems are designed to go 48 hrs plus on battery if no generator is available.

As with any battery's they age with life. so the control system and inverter part is likely still good, the batteries that come with it might be a diffrent story.

 

[stumpfield]

generally UPS's of this type are not designed or optimized for efficiency. They also are usually not rated for 24/7 operation. As a result, it will generate the rated output, but will be a battery hog.

You could do some research at the manufacturer, but you may be better to buy yourself a mainframe so you will have something to protect.

paul

They are rated and use 24/7 in bypass mode. They are good for 10 minutes at the full rated power with the batteries. These are very expensive UPS used at an ISP. Do you think it going to be an asset or liability to my modest solar power system? I don't have constant grid-tie power to maintain them.

 

[SPIKER]

smshism said it that size is good, will probably need batteries soon if not already (depending on age & condition) they generally are as he said conditioners which means they take the in coming power and charge batteries with it and then feed OUT a true sign wave form to the hose system plugged into it...

16kva on 120 is over 100 amps which is BIG for a ups. ours I think is something like a 5kva for our KILN dept, it runs the kilns in case power out. last week we had to shut off in coming power to the UPS and move the sub panel that is between the UPS and the primary transformer. took up little over 10 min it never missed a beat kept going. it had somewhere about 10 amp load on it which stayed going with out loosing anything had 3 kilns 2 computers and all the control sytem on it.! (not the primary power on the kilns just the controls.)

heck I'd be interested in getting one of those myself!

mark M

 

[MossRoad]

I occasionally provide the muscle to remove very large UPSs for a guy that collects junk and sells it on E-Bay. Most of the units he gets for free have good components, but the batteries are usually shot. Disposing of a couple dozen car sized batteries can get expensive, so be careful you don't get stuck with an environmental hazzard.

 

[BobRip]

I agree that the batteries are probably worn, or at least should be questioned.
Running an inverter and then charging it peridically can be efficient as the generator can be fully loaded during charging (an efficient mode for a generator) and then the UPS can be run for many hours. All of this depends on the correct match of the generator size, inverter size, load, and battery size. So the theory is good, but since you don't have a choice of the inverter and battery size it may not work out too good.
If the inverter is oversized for the load then its leakage current (current present even when there is no load) will tend to be high and energy will be wasted with that. This is a brief summary of an area that I am not an expert in. I hope it is helpful.

 

[slowrev]

I have a fewe APC inverters 600W for my electronics stuff, it will run my computer for about 45 min.

My question is can I wire in a bigger battery for more runtime or will the circuitry overheat if run too long ? the additional charging of the bigger battery is not a problem, I can handle that.
I am electronics literate, but not sure how the UPS's are constructed and duty cycle.
Ben

 

[marimus]

I have a fewe APC inverters 600W for my electronics stuff, it will run my computer for about 45 min.

My question is can I wire in a bigger battery for more runtime or will the circuitry overheat if run too long ? the additional charging of the bigger battery is not a problem, I can handle that.
I am electronics literate, but not sure how the UPS's are constructed and duty cycle.
Ben

Yes.

I have a few 1200 watt APC units, which I have extended runtime units for. These are simply an extra battery in a pretty box. The UPS has a connector on the back to plug into, and you can daisy chain upto 4 or 5.

If you get a replacement APC battery for you UPS, you will find it has the same connector, and you can just plug it into the back of your UPS, but you will only be able to plug 1 extra battery this way (no daisy chain).

You also have to program the ups with how many batteries are connected, or else the remaining power calculation will be out. You still get the extended runtime, only it will say you have 30 mins remaining, and then 1/2 hour later you still have 30 mins