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Sure Power 1315A | 12-Volt 100-Amp Bidirectional Battery Separator

SKU 1315A
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Sure Power Bi-Directional Battery Separator |

12-Volt, 100 Amp Battery Solenoid with Auxiliary Start

The Sure Power Battery Separators are designed for use in multi-battery applications, and ensure your Main battery (#1) receives charge first. Once it identifies that charge current is good and flowing to the Main Battery, it will then allow charge current to pass to the Auxiliary battery.

Separator Type : Bi-Directional

A "Bi-Directional" battery separator is able to have two charge sources connected (though only 1 active at a time); one upon the Main Battery, and a second upon the Auxiliary Battery - This means that the charge current can go in two different directions, from the Main Battery to the Auxiliary Battery, or the Auxiliary Battery to the Main Battery. Whichever battery is connected to the ACTIVE charging source will be considered the "Main Battery" as far as the functions of the Battery Separator are concerned.


  • Voltage : 12 Volts DC
  • Amperage : 100 Amps


Auxiliary Start-Assist : (Start Signal must be at least 3-volts to occur)

When the starter is activated, the Battery Separator (1315A) compares the voltage of both your battery banks (Main & Auxiliary). If the Main battery is at a lower power than the Auxiliary battery bank, the solenoid will engage, and connect both batteries to each-other for added starting power.

Protects Charging System :

Once the engine has started, the Battery Separator (1315A) monitors the chassis battery and charging system. When the charging system brings the Main Battery to 13.2 Volts (indicates full-charge), the Solenoid will "Close" which allows current to pass to your Auxiliary Battery. If the drain on the charging system (caused by charging the Auxiliary battery) brings the charge voltage below 12.8 volts, the Solenoid will "Open", which disconnects the Auxiliary battery from charge. It will then bring the Main Battery back to full-charge state (13.2 to 13.4 Volts), it will again "Close" and make the attempt again. This process is repeated until the charge source is removed (turned off). This function protects your charging source, by never allowing it to work itself to "Death" prematurely.

  1. SIMPLE INSTALLATION (instructions can be found below in the "Documentation" above.
    5-connections (3 required) :
    Main Battery to Solenoid (POST/STUD). Solenoid to Auxiliary Battery (POST/STUD). Ground Wire (.250 tab).
    (Optional) : There is one .250 tab for the indicator light, which shows when the "Auxiliary Start Function" is operating.
    (Optional) : Auxiliary Start switch (.250 Tab). Typically connected to the vehicle ignition switch, this can be connected to any properally rated switch.

    The Battery Separator (1315A) waits until the battery connected to the active charging source reaches 13.2 Volts before paralleling and charging the remain batteries. The system disconnects at approximately 12.8 Volts.

    The battery separator allows multiple batteries to be charged from one charging source (usually, but not necessarily, an alternator). When the batteries are not being charged, the Battery Separator separates or isolates the batteries.

    An optional input from the key switch or a manual switch will program the Battery Separator to parallel the batteries during starting. This feature will only engage if the auxiliary battery has sufficient power available to assist in starting.

    If the current requirements are greater then the charging source can produce, the Battery Separator will automatically separate the batteries, thus directing all available charge current to the battery directly connected to the charging source. The system will then reset and re-attempt charging the auxiliary battery. A time delay prevents false switching.

Manufacturer Profile : Sure Power Industries
Sure Power Industries (now part of Eaton/Cooper Bussmann) provides a wide variety of quality products and engineering services designed to aid in the management of DC electrical systems. Since inventing the Battery Isolator in 1959, Sure Power has been designing and manufacturing innovative, reliable and cost competitive products and services for a wide variety of markets including off-highway, bus, and truck, marine and automotive.

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