12v adapter and 12 v 7 ah battery to be charged

[deepakgupta.rf]

here i need this design for industrial purpose please guide me.
i controlled my avr microcontroller and it is working fine for its power supply i used 12 v 1 amp dc adapter and in mid we required power in absense of genral power supply so i used 12 v 7ah smf lead acid battery .
but i m confused is that diagram will work fine.or i need any changes
and regarding fuse i m also confused which fuse ( 1, 1.5 or 2 amp ) ishud use and where i shud place

main thing is when power is continue then i can take power from adapter directoly or if power goes then without any power flicks ican take power from battery and battery can be charged properly through adapter.
so please guide me what i shud do for this

[Hero999]

We don't know because you forgot to post a schematic of the current circuit.

[deepakgupta.rf]

here i am getting stuck to attach my file

[Hero999]

Click Additional Options then Choose.

[mvs sarma]

A tentative arrangement is shown here. the charging element of battery is not included. The fuse F1 is shown before the diode.  Hope it serves the user.

[Hero999]

With a 12V battery and a linear regulator, you're wasting over half of the power. You could use a low dropout regulator and a 6V 7Ah battery which is half the size and it will power the circuit for just as long.

What's the point of the diode? To stop the battery from injecting power back into the 12V supply? You could easily omit it and just connect the circuit to the battery which is permanently connected to the charger. You need to design the charger so that the battery can be permanently connected though.