Sterling Power BB12200 12V 200A Bidirectional DC-DC Battery Charger

The Sterling Power BB12200 is the most capable single-unit DC-DC battery-to-battery charger in the Saturn series, and the go-to choice for serious expedition builds, large lithium conversions, and high-demand electrical systems. We run one in our own EarthRoamer build and have been impressed since day one. At 200A input and 180A output, it delivers 2,600W of continuous charging power — the kind of output that can meaningfully charge a large house bank on a long drive. We typically recommend the BB12200 as a strong starting point for builds in the 400Ah range and above — though the right charger always depends on your alternator capacity, your loads, and how you actually use the rig. Note that this unit requires a 220A+ alternator to operate at full rated input current.

This isn't a basic DC-DC converter sitting at a fixed voltage. The BB12200 pulls up to 200A from your alternator and delivers up to 180A output at a proper 4-stage charge profile — not a flat converter voltage that can damage lithium cells over time. Six preset battery types cover Lead I and II, AGM I and II, and Lithium I and II, so you dial in the correct charge curve for your bank without custom programming. A low-temperature cutoff protects lithium cells in freezing conditions, and six self-recovering protection circuits handle over-voltage, under-voltage, over-current, and over-temperature faults automatically.

Bidirectional reverse charging is standard. When your house bank climbs above 13.2V (13.5V on lithium profiles), the BB12200 automatically feeds up to 60A back to the starter battery to maintain it at a healthy 13.4V — so if solar is looking after your house bank while the rig sits, your starter is looked after too. If the starter ever gets too low to turn the engine over, Jump Start Assist mode forces the reverse charge to run for 20 minutes to get you back in action.

Key Specs:

• Input voltage range: 9–16V
• Rated input current: 200A
• Rated output: 180A at 13.8V (2,600W continuous)
• Reverse charge current: 60A
• Efficiency: 95–98%
• Dimensions: 309mm × 130mm × 96mm
• Weight: 2.2 kg
• Recommended input cable: 70mm² / 00AWG
• Recommended input fuse: 250A
• Recommended output cable: 70mm² / 00AWG
• Recommended output fuse: 250A
• Certifications: CE, UKCA, E-Mark
• Cooling: thermostatically controlled variable-speed fan
• Compatible: lead acid (AGM, gel, flooded), lithium LiFePO4

Compatible with smart/variable alternators (Euro 6/7+). Ignition feed or vibration sense activation modes. Optional BBR remote available for display monitoring, custom charge voltage adjustment, and output current limiting.