Portable UPS

12V? 5A sounds like a car battery will do.

Whats the application?

Respiratory machine..

Two car batteries, of 100Ah each, one on charge, the other powering your respirator for 15-20 hours before swapping over.

As a matter of history, the East Radcliffe ventilator was designed to be powered by the mains, by a battery, and, when all else failed, by a cranked handle. The limited range of speeds was achieved by the use of a bicycle hub gear. From the unofficial manual:

"The East Radcliffe is a real backyard technology machine and seldom stops completely, whilst working in a district hospital in Nepal, one 20 year old Radcliffe we were trying to get going went up in a puff of smoke and stopped, it drew quite a large crowd, the mains motor had seized up through lack of use, it was about half an hour before it was cool enough to handle.
However I am confident that it will be working again as soon we get a new motor."

Try APC.COM

No. I'm not going to do what Google will do so much better.

Try a search on GlobalSpec.

Many UPS suppliers exist, but look into the large well-known ones first but especially check that the UPS is rated for powering medical devices.

Most if not all major UPS suppliers should offer a range of UPS specifically designed for powering medical devices, and yes they will be more expensive than standard UPS because they are tested and rated higher standards.

Here's the UPS product area on Engineering360 (formerly GlobalSpec). You an adjust the filters on the left side of the page to suit your specs.

http://www.globalspec.com/search/products?page=ms#sqid=11203436&comp=5430&show=products&RegEvent=login

If I was doing it, I would simply make one using off the shelf components like these:-

1) Large 12 volt Leisure/deep discharge battery, I would go for 100 A/H or larger, but it needs to be sized for at least twice the size/time you calculate you may need......

2) It was not clear to me if you need this or not, you did not state as to whether it will always be on the mains for charging in between uses....A small 4 stroke generator, I favour Honda for quietness....some even have a 12 volt charging output, but it might not be controllable......so you may need 3)

3) Correct type of charger for the battery type bought for 90 to 240 VAC, with a controlled/adjustable charge level that never tries to get a "full" charge, that is, it must never charge over about 13.6 volts. That will extend the working life of the battery dramatically and stop gassing...I also, do not design a "trickle charge" feature into my own designs, as I am not happy with the results that I have seen. It also reduces to my mind, an extra unneeded complication. But each to his own....

4) Ventilated box for the battery, venting to the open air to get rid of the so called "Knall-gas" safely.

A quality battery, generator and charger are not going to be cheap, but well worth the longterm investment.

Do not use a normal car battery, they don't like deep discharges....if that ever happens of course!! A deep discharge to my mind is ever going below 12.6 volts for more than a few hours, how much below 12.6 also plays a role. Difficult to quantify....my opinion only!!

I hope my "take" of your requirements was similar to yours, but it may not be!!!

I guess it depends on your definition of "portable".

Not fixed down?

Not that anything I mentioned is really heavy, Generator 10Kg, Battery 7Kg aprox....

I was thinking more along the lines of a light weight solution for personal travel and intermittent use where power was available and battery backup was only there in the event power failed and you really needed it, rather than filling up a car boot and going off the grid for days. Hence a small UPS.

Too little info really, little explanation, and important parts missing.

How long must it work for? For example......

Over 2 amps needs to be carefully calculated, but if only for a short time, say an hour, a far smaller charger and battery could be used.....a motor cycle battery may even be enough, or even "D" Cells in a 12 volt pack.....!

If you want portable ups then use your car's ciggy lighter

Please provide more information, what approximate UPS weight are you looking at (just how portable) and how long do you want the batteries to last.

Or did you find a suitable UPS, if so what did you come up with?

Thanks a lot for ur precious time!

what approximate UPS weight= 5 to 8Kg.

how long do you want the batteries to last=2 hrs.

Battery required= (60/12)*2= 10 AH as per calculations but this much battery doesnt lasts for 2 hrs???

Thanks.

What have you found on line so far that you think may do the job?

Let us know and lets see if we agree before you purchase.