12V to 13.8V 5A DC-DC Battery Maintainer | RV Marine Lead-Acid Float Charger

Keep Your Lead-Acid Battery at Peak Charge — Without a Shore Power Connection

Running an RV, boat, or backup power system from a 12V battery bank? The Jason Bang Power 12V to 13.8V 5A Battery Maintainer steps your primary 12V supply up to the precise 13.8V float voltage that lead-acid batteries demand — delivering a steady trickle charge that keeps your auxiliary battery topped off and ready to go, no wall outlet needed.

Unlike bulky smart chargers that require AC power, this compact DC-DC module runs entirely off your vehicle's electrical system, solar input, or any 12V source. It's the ideal solution for dual-battery systems, RV auxiliary batteries, marine deep-cycle banks, and emergency backup setups where maintaining battery health matters more than fast charging.

Key Features

• Precise 13.8V Float Output: Matches the optimal absorption/float voltage for standard 12V lead-acid, AGM, and VRLA batteries — prevents overcharging and sulfation
• 5A Continuous Output (69W): Adequate for maintaining or slow-charging batteries up to 200Ah — ideal for float maintenance and overnight charging
• 8–12V Input Range: Works with 12V vehicle systems, 24V alternators, and solar charge controllers
• Compact Install Size: 74×74×32mm footprint fits under dashboards, in battery compartments, or inside control boxes
• Full Protection Suite: Short-circuit, overcurrent, reverse polarity, and over-temperature protection built in
• High Efficiency: ≥93% conversion efficiency — minimal heat, minimal battery drain from the source
• Plug-and-Forget: Fixed 13.8V output, no adjustment needed — connect and let it maintain your battery automatically

Technical Specifications

Perfect For

• 🚐 RV dual-battery systems — keep your house battery charged while driving
• ⛵ Marine auxiliary battery maintenance
• 🚗 Automotive battery trickle chargers running off the main battery
• ☀️ Solar + battery systems that need regulated 13.8V charge input
• 🔋 Emergency/standby backup battery float maintenance

Important: 13.8V is the correct float/absorption voltage for standard lead-acid batteries. If you're charging a LiFePO4 (lithium iron phosphate) battery, please see our 14.6V LiFePO4 Charger instead — using wrong voltage will damage lithium cells.