Automatic Blackout Switch , Help ?

I have an emergency light in my room , the light turn on when blackout happen
i wonder , can i make my room ceiling light like that ? when blackout happened , it's automaticaly switch to emergency power [ using deep cycle lead acid battery + inverter ] , but when electricity turn on again , the switch turn back using the normal electricity line , and charge the battery
i have trouble design this , can somebody give me advice ? 
the power to handle is 220V , 500W


Lycrois (author) 7 years ago

@crapflinger : maybe , but i wonder how they can make constantly charging with lead acid battery ? 
@Lemonie : yes , i was thinking about using relay , but the problem is , are there any electricty conflict when the main electric turn on ? , if i can do this for my room , i'll make it for any lamp @ my home , i don't want to by gen-set , it's so noisy , too expansive for the silent model , and not worth for just 2 hours blackout

lemonie Lycrois7 years ago
Double pole double throw relays aren't hard to find. You connect the light to the middle terminals, the inverter to one pair of outers and the mains supply to the other. If you wired a mains-to 12V transformer into the mains supply you could use that to throw the relay to mains it'll then fall back to the inverter when the mains goes off.

lemonie7 years ago
If you have persistant problems with power-outages, consider buying a gen-set to back-up the whole house. A standby power supply for one light doesn't seem like the best idea. However, you could take switching from the emergency-power to activate the light you mention - via a relay perhaps?

crapflinger7 years ago
a lot of "always on" type emergency lights like that don't actually use any switching....usually they're actually run off of batteries that are constantly charging....so the batteries that are used to power the lights are wired in series between mains power and the light..