Uninteruptible Power Supply as RV Inverter?

rwbradley wrote:
I hate to add to the bad news... but I considered this myself but based on my experiences with the hundreds of them that I maintain, there were a few things that concern me about this idea:
1) batteries are not cheap and require replacing every 3 years (less than 1 year if you regularly drain them). UPS batteries are designed to maintain a charge (like a car battery), but not meant to be drained regularly (like a Deep Cycle battery). One full discharge can be enough to kill the batteries.
2) batteries are very heavy: a 3000kva rack mount UPS with batteries will come in at about 50-75lbs, a 5000kva will be over 100lbs.
3) most do have fans, but they do not come on until it flips to battery power, at which point they are quite noisy.
4) most UPS's, even the cheap $40 ones are very noisy and irritating when on battery, they beep constantly to warn you they are on battery
5) most UPS's even the cheap ones will beep for everything, brown out, black out, low battery, really low battery, replace battery etc....

Regardless of the quality of power, the weight, type of batteries and noise was enough to turn me off. If you are really concerned, just do something like a cheap APC SmartUPS 350 and use it like a power bar, just for your critical/expensive equipment ie TV, Laptop etc. It will at least give you a really high joule protection rating, smooth out the bumps and give you a bit of time to finish what you are doing. But if you already have an RV Surge Protector on the rig, you already have most of the benefit anyway.

If you are really set on this idea, I would consider something more like this:
http://www.apc.com/products/family/?id=310
I believe these UPS's designed for entertainment systems provide much more "pure" power (term used loosely as I do not think any are true sine).

I was considering wiring this directly to the house batteries. The intent is to use the ups as an inverter to power the coach outlets when not plugged into shore power. I have opened these units up before and simply removed the beeper because they are quite annoying.

I hate to add to the bad news... but I considered this myself but based on my experiences with the hundreds of them that I maintain, there were a few things that concern me about this idea:
1) batteries are not cheap and require replacing every 3 years (less than 1 year if you regularly drain them). UPS batteries are designed to maintain a charge (like a car battery), but not meant to be drained regularly (like a Deep Cycle battery). One full discharge can be enough to kill the batteries.
2) batteries are very heavy: a 3000kva rack mount UPS with batteries will come in at about 50-75lbs, a 5000kva will be over 100lbs.
3) most do have fans, but they do not come on until it flips to battery power, at which point they are quite noisy.
4) most UPS's, even the cheap $40 ones are very noisy and irritating when on battery, they beep constantly to warn you they are on battery
5) most UPS's even the cheap ones will beep for everything, brown out, black out, low battery, really low battery, replace battery etc....

Regardless of the quality of power, the weight, type of batteries and noise was enough to turn me off. If you are really concerned, just do something like a cheap APC SmartUPS 350 and use it like a power bar, just for your critical/expensive equipment ie TV, Laptop etc. It will at least give you a really high joule protection rating, smooth out the bumps and give you a bit of time to finish what you are doing. But if you already have an RV Surge Protector on the rig, you already have most of the benefit anyway.

If you are really set on this idea, I would consider something more like this:
http://www.apc.com/products/family/?id=310
I believe these UPS's designed for entertainment systems provide much more "pure" power (term used loosely as I do not think any are true sine).

I almost did this a few years ago
Until I noticed the track mounted ups system used A 48v battery system, external.. no batteries included

And rack are designed for controlled clean air & temp environments they may have fans, but some don't have cases, like floor mounted ones do

Seems to me like a lot of extra hulabaloo for little advantage. UPS only runs for a little while until power runs out. Usually just used to allow orderly shutdown of equipment, not to run equipment normally.

Um, excuse me for raining on your parade, but do be aware that all the UPSs _I_ have ever heard about are Modified Sine Wave, not true sine wave. $100 is way, way, way cheap for a true sine wave inverter in the 1,000 watt range. In spite of the UPS peddler's best efforts to tout their systems as "safe for computers and other sensitive devices," the fact is that computers, being inherently VERY sensitive, have been designed with robust power supplies so that predictable crummy power, like from $100 UPSs, cause no problems.

The power brick for my Macbook Pro says on it "100-240 volt, 50-60 Hz" input, which says to me that it is a switched and regulated power supply, not a transformer power supply, and that as such, it can handle some pretty crummy power.

Now I'm sure that with enough money and an electrical engineer to design it, such a system could be put together. But not for $100.

I'd have to see one.