Renogy 40A 12V DC-DC Charger

The Renogy DC-DC charger is an efficient way to charge a hotel battery from a starter battery while driving—ideal for campers, vans, boats, and commercial vehicles. It works with traditional and smart alternators and supports a variety of battery types (AGM, lead-acid, gel, and lithium), providing intelligent 3-stage charging (bulk/boost/float) for maximum efficiency. With input/output separation and a range of safety features (including overvoltage, overheating, and reverse polarity), it protects the system, starter battery, and power bank, extending battery life and improving operational safety.

Renogy 40A 12V DC-DC Charger

• Compatibility with many types of batteries and alternators
  Charges AGM, acid (Flooded), gel and lithium (LiFePO ) batteries and works with traditional and "smart" alternators.


• Smart 3-step charging
  Bulk / Boost / Float modes ensure automatic, optimal charging of your hotel battery to 100%.


• High safety and protection of the installation
  Input/output separation and safeguards (overvoltage, overheating, reverse polarity) protect both the starter and hotel batteries.

Main features

• Charging from a DC-DC alternator


• Works with smart alternators


• Supports AGM, GEL, LiFePO4


• Smart 3-step charging


• Input and output separation


• Overvoltage protection


• Overheating protection


• Reverse polarity protection


• Protects the starter battery


• Charges the hotel battery from the starter

While driving, it transfers energy from the starter to the hotel bank in a controlled, safe manner.

Smart 3-step charging

Bulk/Boost/Float modes adjust the charging process to quickly and correctly charge the battery.

Key Features

• Supports traditional and smart alternators
  Works in both older installations and modern cars with intelligent charging control.


• Input and output separation
  Isolating the sides reduces interference and prevents the transfer of incorrect voltages between installations.


• Overvoltage protection
  Protects electronics and batteries when the system voltage exceeds a safe level.


• Overheating protection
  Limits operation or disables charging when temperatures are too high, increasing safety.


• Reverse polarity protection
  Designed for off-road driving and working on water, so that the equipment does not "get" affected by vibrations.


• D+ input protects the starter battery
  The charger only starts when the engine is detected, which reduces the risk of discharging the starter battery.

Specification

DC-DC charger 12V 40A

• Voltage: 12V


• Current: 40 A


• Output power: 500 W


• Current consumption at rest: < 0.4 A


• Input voltage range: 8-16 V


• Equalization Voltage: None (N/A)


• Float Voltage: 13.2-13.8 V


• Charging voltage (Boost): 14.1-14.7 V


• Operating temperature: -20°C to +50°C


• Dimensions: 261 × 175 × 68 mm


• Weight: 1.9 kg