Sterling Power BB12120 12V to 12V battery to battery charger, for charging a second battery bank from the alternator or another battery.

• 12V input to 12V output
• Lead-acid and lithium charge profiles, with preset and user-defined settings
• Bidirectional, with Jump Start Assist
• Current limiting and parallel operation
• Activated by ignition feed or vibration sensing
• Compatible with Euro 6+ smart alternators
• Optional BBR remote available

Specifications are from Sterling Power. Check the manufacturer documentation for installation details.