220v-12v Logic Gate

Why not just get some 220v LED's??

http://www.alibaba.com/showroom/220-volt-led-light-bulbs.html

You said "i dont have 220V all the time" but you also said you have a UPS. I expect the UPS to give you 220v, if it does, you can just replace the lamps as in #1 by SE. This is easiest and safest.

Welcome to this forum.

I assume that you want the 12v LED to be energized when the power goes off. It sounds like you need a 230 v relay with the 12v circuit wired through the normally closed (closed when not energized) contact. When the juice goes out, the relay drops out, closing the 12 volt circuit through the relay. I'll type fast so you can read it before your electricity goes off.

You would need a manual fail safe switch for that setup.....

Wouldn't the control card out of a emergency light do. That is what it's design for.

use this and a 12v battery, or just this

and the switch ??

Fredski's answer is probably best. To explain further, your lamps would all be 12V, all the time, and powered by the 12V battery, which in turn would be charged by a 220V/12V charger. The battery size would be dictated by how long your 220V power interruptions could be, together with how many lamps you need to run and for how long.

yep

They could still use 230 v lights when the power is on.

I agree, Fredski's solution has the advantage in that it is off the shelf and a lot safer than mucking about with 230 v power. GA Fredski!

If you want to keep the 220V lamps and omit any 12V lamps, you can use a UPS (uninterruptible power supply), which consists of a 12V battery, a 12V to 220V inverter, and a transfer relay. This is more expensive than the battery/charger combination mentioned before.

It also does not achieve a good efficiency either....sadly.

There are nowadays, many mains charging LED "torches" or "Flashlights" cheaply available on ebay and the like that ONLY need mains (you can buy them for 220 VAC and 120 VAC).

They sit in the mains charger when not being carried around and they can be set to go on when there is a mains failure, or just sit there ready and charged in case light is needed.....

The beauty being that even if one goes wrong (unlikely) all the others are still available for use.....also, no extra wiring or rewiring or other parts to buy, a pure "off the shelf" functionality.

Also, if money is a problem, buy them singly over a longer period.....try and buy ones that use standard rechargeable batteries, so if the batteries age over time, you can easily replace them....

There are also similar units available, which are mounted on the wall or ceiling which have a battery and CAN BE SET TO GO ON WHEN THE MAINS FAILS.

Its called emergency lighting, see here for a few ideas:-

emergency-lighting

Emergency+lighting

LED-Emergency-Rechargable-60-LED-Lantern-Torch

Agreed. Most emergency lighting is inefficient, but that doesn't matter much, because it is not often in play.

Wait a second! You want to put 12 VDC on the same lines as the 220 VAC when the 220 VAC is absent? How do you keep from burning up your 12 VDC power when the AC comes back on?

Your controls need to act very quickly or there will be smoke and an unpleasant burning smell.

Your lighting that runs on 220 will have to be isolated from your DC supply with a series capacitor that will block the DC or the AC load will consume power from your DC circuit. Is this in keeping with your question?

Leave it alone. Engage a qualified Electrician, who will be able to effect an installation compliant with the local electrical installation standards.

If he had taken on my idea, no designing or electrical work needed as they can plug into any vacant socket!!