July 7, 2015 at 7:49 am #7292
Inactive
It really depends on how long they need to run the system in case of a main power failure and what their overall current draw is. The way to calculate the draw is to identify the current draw for each device connected to the power supply is and add that up. That will give you the total draw and then you calculate how long it needs to run without main power and go with that battery.