Register and enjoy 5% off for new orders!

12V 40A DC to DC Battery Charger

SKU: RNG-DCC1212-40-AU
Write a Review
 reward Renogy Rays
Load More
12V 40A DC to DC Battery Charger
12V 40A DC to DC Battery Charger
Add to cart
Adding to cart… The item has been added
Shop alone
Start group buy
12V 40A DC to DC Battery Charger

Method of payment
Return & refund policy
Write a Review
Free Shipping
Reliable Warranty
Secure Payment
Key Features
-Compatible with multiple battery types.
-Smart 3-stage charging: bulk, boost, and float.
-All-round electronic protections for ultra safety.
-Protect your starter battery.
-Compact and robust design with CE certification.

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! Click here to know more about the inverter of the 2nd bundle option: Renogy 2000W 12V to 230V/240V Pure Sine Wave Inverter (with UPS Function)! If you have any questions regarding this product, please submit a case !

Empower Your Journey on the Go
Maximize charging efficiency on the go with enhanced versatility.
Compatible with Multiple Battery Types
The DC-DC battery charger is highly compatible with AGM, Flooded, Gel, and Lithium batteries, ensuring optimal performance for various battery types.
Seamless Charging, Ultimate Safety
Isolated input/output with multifunctional safety technology for error-free and secure house battery charging.
Protect Your Starter Battery
Renogy's DC-DC battery charger works seamlessly with traditional and smart alternators. The included D+ Ignition cable identifies generator starts, safeguarding the starting battery from over-discharge and protecting the generator. (Recommended: 18-16AWG copper cable. D+ Ignition Cable not included.)
Smart Charging Protection
The DC-DC battery charger's LC wire automatically adjusts the charging current, safeguarding the house battery from potential damage due to excessive charging. (Recommended: 18-16AWG copper cable. LC cable not included.)
Smart 3-Stage Charging
Efficiently charge your house batteries from the starter battery with Bulk, Boost, and Float stages, ensuring automatic and optimal charging up to 100%.
Prolong Battery Lifespan
Automatically adapts charging modes to match battery voltages, while the temperature sensor provides -3mV/°C/2V compensation, ensuring optimal charging in varying temperatures. (Please note: Temperature sensor not included, not compatible with Lithium batteries.)
Explore the Complete Connection
Going solar is not that complicated. Renogy is here to help you build your system faster so you can roam further.
The Renogy Difference
Going solar is not that complicated. Renogy is here to help you build your system faster so you can roam further.
Connect with Renogy customers.
Go to Power Plus Community
Still have questions?
Ask our specialist


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  
Package includes:  
The first option: battery charger x1 The second option: battery charger x1 and temperature sensor x1

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

49 Reviews Hide Reviews Show Reviews

  • 5
    Haven't fitted yet

    Posted by jgoo9994 on Sep 4th 2023

    Haven't fitted yet

  • 5
    As described

    Posted by xtechnic on Aug 8th 2023

    As described.

  • 5
    Good dealing.

    Posted by 717garryb on Aug 7th 2023

    Good dealing

  • 5
    Good dealing

    Posted by 717garryb on Aug 5th 2023

    Good dealing.

  • 5
    Great product and delivery time

    Posted by mattandweet on Aug 3rd 2023

    Great product and delivery time.

  • 5
    Fast postage and quality item

    Posted by getarota on Aug 1st 2023

    Fast postage and quality item, thanks.

  • 5
    fast delivery

    Posted by lasijczuk123 on Jul 25th 2023

    fast delivery

  • 5
    Haven't fitted yet

    Posted by jgoo9994 on Jul 21st 2023

    Haven't fitted yet

  • 5
    Was suitably packaged and arrived in a timely manner

    Posted by treane on Jul 14th 2023

    Was suitably packaged and arrived in a timely manner. Unit seems to be exactly as described. Would buy from this seller again.