trickle charger for 14AH battery?

hi, i am looking into making a 12v UPS for my home cctv system. i have two 12v 7AH batterys like the type used in fire and burglar alarm panels.
my aim is to have a 240v input which gets converted to 12vdc and powers my dvr and cameras. the power supply of the dvr alone is 5 amps so i would need 1 5 amp output and then 16 lower amp outputs for the cameras but i guess this could just be done with fuses.
now, here is the tricky part: in whilst also powering the dvr and cameras, i also need it to charge my two battery's wired in parallel so theres 14 ah of 12v battery's to charge (i may also add more at a later date). in the event of a power loss, a relay or some other switching device will switch power to all the devices to the battery so that its backed up.
the only problem is that i am new to battery charging and don't fancy blowing them up.
schematics, help suggestions all greatly appreciated.
thank-you. - Luke

marksnix5 years ago
I am currently looking in a somewhat similar problem for my CCTV camera except that I am wanting to set up a battery backup system to run my camera from a long distance. I think you are going to run into a problem that I was thinking which is that your DVR is going to drain your batteries really quick not counting your camera. I will get back with you but I think the way I am going to get around that is to power up the camera and recorder only when motion has been detected. I have a PC with a capture security card in it that allows this from the software but I could also install a seperate motion detector at the camera. Just wanted to run these ideas past you in case it might give you some ideas. Good luck.