Cars may experience drained batteries for a variety of reasons, such as drivers leaving the lights on, too many power-hungry aftermarket accessories, and driving that requires many short trips with lots of engine starting. Battery Brain maintains enough battery energy to allow an engine start by monitoring battery charge and drain, disconnecting the battery before it drains completely. This device has the obvious benefit of preventing motorists from getting stranded with a car that won't start. Battery Brain comes in three packages, designated I, II, and III. The I level has the basic Battery Brain unit that monitors the battery and disconnects it if necessary. The III level includes two remotes for remotely resetting the Battery Brain unit if it disconnects or forcing a battery disconnect to prevent theft.
The Battery Brain unit is a small, gray box with battery connectors on the sides and a yellow on/off switch on top. It is designed to be connected between the positive pole on the car battery and the car. To accommodate differing battery-compartment sizes on cars, the unit allows for flexible mounting positions, either on the top of the battery, on the side, or directly to an interior panel of the car. Its battery-terminal connector is a separate piece and can be mounted directly to the Battery Brain unit or with a cable to let the unit sit away from the battery. Extra holes in the unit's bottom plate and included hardware facilitate mounting it to the car body. Battery Brain III includes two remotes the size of standard key fobs.
There are no settings, besides the on/off switch, on the Battery Brain unit. All of its logic concerning when to disconnect the battery is preprogrammed. Presuming that it's set to handle heavy-duty starter motors, it will most likely disconnect the batteries of cars with lesser starter motor-power requirements before it really needs to, although that's not likely to be an actual problem in use. The biggest concern is that most modern cars require power flow at all times to maintain clock and computer settings; it would be inconvenient to have to frequently reset everything. Battery Brain takes care of that issue with a bypass cable that plugs directly into the fuse box, letting installers determine which devices need power at all times.
Battery Brain looks like a good investment for older cars or people who frequently leave their lights on. It won't fix faulty generators or reduce accessory drain, but it will ensure that drivers won't be stranded.