Comments on: Installing Batteries in a Liebert GXT2-2000RT120 UPS

By: Adam

Adam — Sun, 14 Apr 2013 17:06:29 +0000

Recently stumbled on this:

http://www.ebay.com/itm/Furman-ADP-1520B-Adapter-Cord-20-Amp-Socket-to-15-Amp-Plug-w-Internal-Breaker-/300855702419?pt=US_Pro_Audio_Parts_Accessories&hash=item460c65b393

I thought I’d but it here.

By: Bob Balan

Bob Balan — Sat, 30 Oct 2010 09:01:58 +0000

These units have a port for daisy chaining battery-only expansion cases to increase the run time, no need to daisy chain ups to ups through the power outlets, just add an external battery cabinet. At 50% load the internal battery is rated for 14 minutes. With one battery cabinet it jumps up to 42 minutes. With 4 battery cabinets at 50% load its rated for a nice cool 210 minutes. My units are ready for batteries as well. Thanks for the link to reasonable replacements.

By: Chris Wescott

Chris Wescott — Mon, 04 Oct 2010 22:18:57 +0000

Steve,
I had bought 4 used GXT-1000VA and got lazy when testing the last one and plugged it into the back of 1 GXT that was already being powered from the wall plug. This popped a fuse inside the unit (one not plugged into the wall) I opened the cover and replaced the fuse, then before replacing the cover I powered the GXT from a wall plug and a nice blue flamed fire started for a few seconds completely frying the rest of the ups.

So in short, besides being inefficient, it can be dangerous. There is a chance that I received a bum unit but it did work before I brought it to the office.

It would be interesting to know if Daisy-Chaining this type of UPS works.

Chris.

By: Keith Neufeld

Keith Neufeld — Mon, 23 Aug 2010 15:27:33 +0000

Steve, it’s possible you could chain them; but they’re not designed to work that way and you’d lose efficiency to the repeated DC/AC/DC/AC conversions.

If you have multiple small loads you want to power, you’d probably be better off putting each load onto a separate UPS for longer runtime.

By: Steve Jesiolowska

Steve Jesiolowska — Tue, 17 Aug 2010 14:02:38 +0000

Keith, thanks for such a nice explanation on how to replace the Batteries of a GXT2-2000RT120.
I’d have a question that you might be able to help me answer…
I just purchased 6 additional GXT2-2000RT120 UPS’ at an auction and was wondering if I can plug them all together and have 6minute of battery backup times the amount of units (so 6 unit * 6minute of backup time = 36minutes of battery).

Thanks!

By: Anonymous Coward

Anonymous Coward — Tue, 20 Jul 2010 01:19:53 +0000

Adam: Online units like this know exactly how much power they’re putting out, and can electronically limit themselves to certain amounts of power for specific amounts of time. If a unit like this starts to overload, it’ll first start squealing at you, then cut over to an internal bypass, at which point it’s up to the main panel breaker to trip if there’s really too much power going through. On a dead short, they’ll just switch off entirely to protect themselves and whatever poor creature might be chewing on to the wires.

Keith: Call the Emerson folks at 1-800-222-5877 ext 1. They used to send out replacement panels from their returns depot a couple years ago, no questions asked. There’s a GXT3 out now, though, so covers might be a little harder to come by.

By: Jon

Jon — Tue, 29 Jun 2010 03:30:47 +0000

I have a similar UPS rated at 1200 VA. It also has 4 batteries but they are in a series/parallel arrangement for 24V.

Its batteries were also shot. I used two large marine deep-cycle batteries. I figure about 60 amps at full load!

Routinely, the UPS powers the network gear and the all-important tankless gas hot water heater In the event of a long power outage, I can also plug in the furnace to keep the chill off for a day or two. So far, it’s been a great preventive measure – haven’t had an outage since I put it in last fall

By: Adam

Adam — Mon, 28 Jun 2010 20:15:29 +0000

Yes, quite annoyed indeed.

I bet it lets you “steal” transient load capacity from the battery banks…

Looks like a really nice unit. If you ever crack this bad boy open, be sure and take pictures. I’d love to see the electronics.

By: Keith Neufeld

Keith Neufeld — Mon, 28 Jun 2010 19:51:13 +0000

Agreed; they doubtless limit the aggregate current.

Still, the design makes sense. Say you wanted to power a single 15A load — you’d be quite annoyed if you couldn’t put more than 5A on each of the UPS’s receps.

By: Adam

Adam — Mon, 28 Jun 2010 19:44:06 +0000

No, I guess not I just wanted your input on best practices and when it was ok to break which rules…

I couldn’t help myself and looked up that the input power was 1400W max, that’s 11.7A @ 120V. I’m sure most of that is in-rush and max charge power, you also have (4) 5-20 “T-Slot,” which I assume are just (4) 5-20R’s. So, it looks as if, if all 4 outlets had a full 20A load, and the UPS was fully charging, you would be drawing 4*20A+11.7A=91.7A! I know that will rarely happen in practice, but….

How can they wire (4) 20A sockets over (1) 20A plug, there must be an internal 20A fuse/breaker on the UPS mains?