Backup battery and charging module

Hi, I've been searching all over the internet for clarification on this topic, and I thought someone on here could help me out. I have a tracking device I bought for my car, and I bought a battery backup, so I could continue to track the vehicle, even if a theif disconnected my car battery. The battery backup I got came with a charging module (Model BBT2M from Micro Alarm Systems... and no, they didn't have any additional instructions on it), and only included the following instructions (the module has a gray, black, and red wire out of one end, and a black and red wire out the other):

Gray = Red to Alarm

Black = Ground

Red = 12 Volt Constant

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Red = To back up battery

Black = To back up battery

I've drawn up a schematic diagram, and I just wanted to make sure I was doing it right before I continued. Thanks for any help. Here's the diagram: