How do you reconnect the battery to the electrical system?


Depending on what model you have there are several different ways to reconnect to the electrical system.
The Battery Brain T3 has the manual reconnect option and a remote control to reconnect and disconnect. Since you are able to disconnect the unit it can be used as an anti-theft device.
Once you leave your vehicle simply press the disconnect button and it can’t be hotwired or stolen.
The  Battery Brain T4 has a manual reconnect option and a wired push button reconnect and disconnect option. The wired push button micro switch can be mounted anywhere you choose.
The Battery Brain T4  is specifically made to protect 12v RV (recreational vehicles) or coach batteries. Since it may not be responsible for starting a vehicle the charge protected is at a threshold of 10.5V. It avoids the discharge and recharge cycles that can significantly reduce battery life.