Another UPS question

[bilbo7500]

I've searched for the answer, evidently, I'm "search challenged", as I didn't find what I was looking for.  All information I found was how to make a charger.  I want to know if I can make just an inverter from a UPS.  Sounds easy, just hook it up to 24vdc source and - bingo.  But I find that it's not quite that easy.  Either that, or the "dead" UPS's I have are just that, anchors.  I have several, all 24vdc.  The largest one is a Tripp Lite Smart 2200.  There is something wrong with all of them, but none the components look like they've had the smoke released.  They all have nice transformers, relays and bridges with nice heat sinks.  The largest transformer has 8 - 8 guage wire connected to the bridge/heat sink - 4 to one side and 4 to the other.  The other side of the transformer has 5 - 12 gauge wires that are connected to various relays.  It's all nice looking stuff.  Is it at all possible to make an inverter from the components - 24vdc in - 110vac out?

Moved to a more appropriate section.

[Kronk]

Funny you should post this I have been googling for info on how to do the exact same thing as i have some APC's and PowerWare's sitting around. What I have found is that obviously the units can create 120VAC from 24VDC however how a UPS reacts to a battery bank that has to regulate a charging load is another thing. The UPS's software may indicate that it has bad batteries and shut down. Also increasing the AH capacity of the battery bank may exceed the threshold of some of the components in the UPS.  One other thing is most UPS's do not have a sinusoidal output, a sinusoidal inverter costs big bucks anyways, but its worth noting that square wave inverters have limits for what can operate on them. eg anything that uses the 60Hz or 50Hz output for timing such as digital clocks.  

I plan on just hooking mine up and seeing what happens if I ever get my turbine built... Another more involved path could be to use the components in the UPS to build your own inverter if your handy with a soldering iron and can find a decent schematic.  

Best of luck if you find out anymore info please share it.

Ken

[Kronk]

Sorry I didn't read your post correctly... I need an edit button.  Anyways i have used this site http://forum.allaboutcircuits.com/index.php a number of times for ideas for circuits.  Keep in mind though that modified sine wave inverters are available for really cheap.

Ken

[tomtmook]

Tripp Lite won't give you schematics and they discourage allowing you to repair or modify their units on your own.  My guess is that they want to limit their liability if the unit burns down your house.  So unless you're an ex-Tripp engineer, or really good at electronics, there probably isn't much hope.  

It does seem a shame to toss those big, expensive transformers.  Especially when it's probably something simple that went wrong with it in the first place.  Still you may be able to salvage some of the components for tinkering if you're so inclined.  

[dnix71]

The "Smart" series of APC brand are true sine inverters. I can't speak for TrippLite brand.

I usually avoid TrippLite backup light/inverters because they used batteries that were not the common rectangles that can be easily replaced with generic sla's.

I have used a cheap APC brand ups for an inverter, just by connecting it to a 12v marine battery. As long as the battery was fully charged first, it didn't care. It cost too much to replace the internal conpared to buying new and it was a square wave inverter, anyway. I didn't want another mod sine inverter, I just wanted to see if it worked.

[dnix71]

The inverter you have (a 2200) sounds like a rack mount made to back up blade servers. If the internal batterries are good, there should be a place to connect an external pack for extended run times.

[wdyasq]

UPS unit s are not well suited for inverters. They tend to be inefficient and are designed for short duration loads.  

A good Google search of the board should bring up many stories of woe and UPS as inverters.

Ron

[pvale]

It might be a good idea to hook up and check all of your Powerware units. I have a Powerware UPS that turns out to be true sine wave, and has a pulse battery charger in it to keep the batteries desulphated. Plus it will cold start. Too bad it works on 60VDC. I bought some new SLA batteries to go inside it, and it does have an external input, but 60VDC is so odd, I can't even find a DC-DC step-up convertor from 12VDC to 60VDC so it would work from my main 12V battery bank. Too bad, it's a 1000W UPS.

P. Vale

[dnix71]

There is a review on the TL 2200 here: http://www.pcmag.com/article2/0,1895,30518,00.asp

It's 7 years old. It was a server rack mount model and came with line conditioning, but I doubt it was made to run indefinitely on batteries. It will run for 7 minutes under full load : http://www.frontierpc.com/productDetails.aspx?productId=202032647

Just a battery replacement will set you back $250 incl shipping.

http://www.apexbattery.com/tripp-lite-smart-2200-ups-battery-ups-batteries-tripp-lite-ups-batteries.
html

[veewee77]

Simple answer. . .

Many UPSs will not start unless they detect 60hzAC on the inputlines first, and if they pass the power-on battery test.

UPSs generally aren't that efficient because they are designed for short-term, emergency power only. Who cares if it runs a long time, as long as it runs long enough for a clean shutdown.

You can rig some up and make them work, but it it likely you'll be disappointed in their abilities, inefficiencies and shortcomings.

Doug

[domwild]

Here is my 2c worth:

1. Your UPS may not cold-start. Hook it up to mains, switch mains off, then it may start. From memory, switch DC on first, then mains.
   
2. UPS as inverter - you may have to add on an extra fan from a PC CPU or PSU to cool the heatsink where the FETs are sitting on as the UPSs are designed for only a short-time AC delivery.
   
3. If you are using batteries other then the common SLAs, which come with the UPS in a separate box, then remember, an SLA is being charged at a slightly lower terminal voltage. Something I found out by using large car batteries instead.
   
   

Good luck!

[bahnfeldt]

UPS are a  inefficient waste of time if on solar only - the modern industrial ones i have serviced  and maintained , would be worth a shot if you had hydro or good wind for battery charging

of course ups have a high dc input normally and be bloody careful poking around inside when fired up with 400 vdc on the bigger ones