12V 40A DC to DC Battery Charger
5(5) 12V 40A DC to DC Battery Charger
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SKU: RNG-DCC1212-40-AU
AU$209.99 AU$169.99
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The 40A DC to DC Battery Charger is the most effective way to charge your house/secondary batteries from the starter battery. Compatible with a multitude of alternator types, the DC-DC battery charger offers correct charging for AGM, Flooded, Gel, and even Lithium deep cycle batteries! Featuring a 3-stage battery charger and multiple electronic protections, users can feel confident that their batteries are being charged optimally and automatically. For additional safety, it isolates the input from the output preventing incorrect voltage transmission. Easily install the compact yet sturdy DC-DC battery charger on RV's, commercial vehicles, boats, yachts, and many more applications!

If you have any questions regarding this product, please submit a case !

Key Features

  • Compatible Multiple Battery Types: Compatible with a multitude of alternator types, the DC-DC battery charger offers correct charging for AGM, Flooded, Gel, and Lithium batteries.
  • Various Protections For Ultra Safety: The DC-DC battery charger isolates the input and output to prevent voltage transmission errors and interfere with house battery charging. It has multifunctional safety technology including over-voltage protection, over-temperature protection, and reverse polarity protection to make it safer for use.
  • Protect Your Starter Battery: This Renogy DC-DC battery charger is compatible with traditional and smart alternators. The D+ Ignition cable is capable of identifying whether the generator is started, to prevent over-discharge of the starting battery and protect the generator. 18-16AWG copper cable recommended. Please note the D+ Ignition Cable is not included.
  • Smart 3-stage Charging: The DC-DC battery charger will charge your house batteries from the starter battery by 3-stage charging (Bulk, Boost, and Float), to make sure it optimally and automatically charge to 100%.
  • Protect Your House Battery: The LC wire can automatically adjust the charging current to prevent excessive charging current from damaging the house battery. 18-16AWG copper cable recommended. Please note the LC cable is not included.
  • Prolong Battery Lifespan: The charger needs to select the charging mode according to the battery voltage. By utilizing the DC-DC temperature sensor, this charger is able to protect your battery from high or low temperature by giving -3mV/°C/2V compensation so that the charger recognizes the voltage more accurately and assures stable and constant charging to the battery. Please note the temperature sensor is not included and it cannot use with Lithium batteries.
  • Compact, sturdy design, built tough for all conditions.

Package Includes

40A DC to DC Battery Charger

Renogy 40A DC to DC Battery Charger

1 x


Renogy 40A DC to DC Battery Charger  
Nominal Voltage: 12V Rated Charge Current: 40A
Output: 500W Idle Power Consumption: <0.4A
Input Voltage Range: 8V-16V Equalization Voltage: N/A
Float Voltage: 13.2-13.8v Boost Voltage: 14.1-14.7v
Operating Temperature: -20°C to +50°C Dimensions: 10.28 x 6.88 x 2.68 inches / 26.1 x 17.5 x 6.8 cm
Weight: 4.14lbs / 1.88kg  

Warranty Information

Accessories 1-year material warranty


1. What is a DC-DC charger? What is its purpose?
The DC-DC battery charger is installed between the starter battery and the house battery. For the RV system, The generator ensures stable power supply to the starter battery, and uses the extra power of the starter battery to supply power to the house battery.
2. How to choose a suitable battery charger?
1. Make sure that the entire system is a 12V system 2. Ensure that the maximum charging current provided by the DC-DC battery charger does not exceed the maximum charging current allowed by the house battery
3. How to set the charging voltage value of the charger?
The DC-DC battery charger adopts the design of the DIP switch and it provides 6 charging voltage settings through five gears. These six charging voltages meet the requirements of lithium batteries and lead-acid batteries in order to provide more charging options. SW5 switch is the selection switch for switching between lead-acid batteries and lithium batteries.
4. What is the D+ Ignition cable? Is it necessary to connect?
The D+ Ignition cable is a design method used to identify whether the generator is started. This design method can well prevent the starting battery from being over-discharged during the charging process. When the generator is started, a signal will be obtained on the D+ Ignition cable, which will light up the indicator light of the charger. The DC-DC will not power on or operate until the D+ ignition cable is connected.
5.How can I get these cables?
The battery temperature sensor for DC-to-DC car battery chargers can be purchased at the Renogy store. The D+ ignition cable can be purchased at the local store or online, it suits both D+ and LC terminals. 18-16AWG copper cable recommended.
More questions about your off-grid power system? Learn more from Renogy Learning Center!
12V 20/40A DC to DC Battery Charger w/o Solar Input Datasheet
12V 20/40A DC to DC Battery Charger w/o Solar Input Maunal

Reviews Hide Reviews

40A DC-DC Battery Charger

Rob Cooper on Sep 5th 2022

Easy to install and well made. This charger was chosen for price and capability.


Bob L on Jun 23rd 2022

Great charger, chargers at a full 40 amps, fantastic for the money


Alan Brayne on Jan 11th 2022

The 40amp DCDC charger I purchased is of a very good quality and is well priced.

Renogy 40 amp dc to dc charger.

Ian Werfel on Mar 14th 2021

Absolutely impressed and very pleased with this device. Have no worries now with running our caravan refrigerator now and the lithium batteries maintained in a fully charged state with no concerns.

DcDC charger

NEIL GLOSTER on Feb 2nd 2021

This was recommended by a friend and so I purchased one its a great product a 20 amp and a 40 amp charger in one unit and it has now been fitted to my ute and the 2nd battery has never been better !! charged properly now its runs fridges and other things and its great all due to the charge !!!