inverter wiring

A simple way would be to have a mains-powered relay and use the N/C contacts in line with the supply to your inverter. If the mains is there the relay is energized and these contacts are held open. When the supply drops out they will close and switch on your inverter. You will need typically 10mA to run a relay, at 240V this is 2.4W of wasted energy. If you have a switch in line with your relay supply you can choose to save energy and allow the standby to work when you feel it is needed.

There are more complicated electronic solutions, but they are not as easy to describe.

.....is it just inverter circuit without battery or with battery ,if complete unit than most of inverters do employ auto switching , but provide complete supply whether supply is there or not, Emergency lighting circuits use diode transistor capacitor circuit to switch from mains mode to battery mode or relay just mentioned by our member.......

Hi Potdarps,

The simple way is buying 3 emergency power off lamp.

It will automaticaly light if poweroff and recharge when power on.

do they make spdt switches or any double throw switch for your mains light sw? I would look into that sol'n.

Why not power the charger continuously from the main, run the inverter continuously, and run the cf's off the inverter. Much the way a laptop running off the charger works. If the main power goes dead you simply stop charging until it comes back. Lots cheaper, no switching and you always know if the system is working (because it is!).

Semi retired designer, you idea is basically sound provided the charger is one that senses when the battery is fully charged and then automatically reduces to a small "holding" current.

The same mains voltage that is supplying the charger should be sensed to decide when to turn on the inverter - mains gone, turn on inverter....

A slightly better refinement is to add a "daylight" sensor to only allow the inverter if its dark outside.

Adding switches at suitable points allows you to test and control various functions even during the day.

Do remember that you only have 45 watts of mains voltage:-

a) more than enough to kill you if a careless design is made

b) thats not many fluorescent tubes, I would not go near the 45 watts usage and would say only use 3 x 8 watts max......even that might be pushing the envelope too much.

Some say a better method would be to have bought 3 x 8 watt fluorescent units built for camping on 12 volts, each has its own inverter and uses the tubes more efficiently as the frequency is much higher and its difficult to contact anything that might kill you! then you only need to sense as I mentioned before and only run 12 volt wires instead of mains.....also, if one unit goes down, you still have 2 working!! Whereas if the inverter goes down, you have zilch.....

There are other areas of "single point of failure", but these will not be as stressed as the inverter and less likely to go wrong.

Remember that 12 volts from a lead acid battery can burn you quite badly if you make a short circuit (watch or wedding ring etc)....lots of good fuses everywhere is a good move!!

"I want to lighten my home with three CFL tube lights."

Are these complete-fittings ie Just place/ hang somewhere & connect to Source-Power.
It seems that these are; then why not to purchase:
"3 emergency power off lamp." as suggested by nam70
Have backup battery & switch on failure of power. Inverter becomes redundant.

To learn all this another choice' you should continue by learning.
One of the CR4 poster says:

"One who asks a question is a fool for five minutes; one who does not ask a question remains a fool forever. "

My instructor addressed the class after Final results:

" To learn never hesitate to ask & never refuse to impart knowledge "


If not?
I don't know the regs allow open wiring at your locality.
You have to install wiring for your CFL tube lights including "mains-powered relay ",
with Change-over contacts.
But in any case you have to care to switch on-&-off manually, unless you like to keep always On.