I had a good friend to send me a commercial emergency back power supply and surge protector with a new 12 volt 9amp battery.
The manual states that it would power a desktop and LCD screen for approximately 1 hour.
It has 4 surge and noise protected outlets that operate continuously and 4 outlets that provide backup power along with surge and noise protection.
It is designed to only charge the battery when plugged in an AC outlet and the power pack turned "on".
Step 1: connecting the 12 volt wires and plug
So I connected 2 wires to both terminals on the batteries and ran the wires through some vent holes.
Using wire splice connectors, I connected an existing 12 volt cigarette lighter terminal to the wires running from the battery.
I used the wire splice clips to keep the plugs that I had already had wired to the cigarette lighter terminal.