Thanks to those who responded on my previous question about quality smoke detectors for sprinkler system. What I choose was a standard 6 zone alarm panel,(monitoring purposes duhh) for the smoke detectors(I got hold of some amdeco versions cheap & new) and will use the siren output of the alarm panel to activate the electronic water valve.
I have a 12V bank of 2volt 200ah Cells(ex PMG 1971 models..lol)which I plan to use as a UPS for powered locks on external steel doors for fire safty purposes obviously,power off,doors open so on. What is the cheapest and most easy and efficent way to use these battery's for my 12VDC devices? Power all devices directly and charge the batteries with a regulated charger from mains or wreck an old commercial UPS and add the cells in series?