Renogy 12V 40A DC to DC On-Board Battery Charger for Flooded, Gel, AGM, and Lithium, Using Multi-Stage Charging in RVs, Commercial Vehicles, Boats,…

(3 customer reviews)

Original price was: $189.99.Current price is: $129.99.


  • 【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.
  • 【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%.
  • 【Various Protections For Ultra Safety】 Offers Over-voltage Protection, Over-temperature Protection, and Reverse Polarity Protection to ensure the operation safety. It also isolates the input and output to prevent voltage transmission errors and interfere with house battery charging.
  • 【Protect Your Starter Battery】The DC-DC battery charger is capable of identifying whether the generator is started, to prevent over-discharge of the starting battery and protect the generator.
  • 【Reliable Quality】The compact and robust design makes it suitable for all conditions. CE certification.

, Renogy 12V 40A DC to DC On-Board Battery Charger for Flooded, Gel, AGM, and Lithium, Using Multi-Stage Charging in RVs, Commercial Vehicles, Boats,…, 159.99, USD,

Additional information

Package Dimensions

11.97 x 8.62 x 4.49 inches

Item Weight

4.82 pounds



Country of Origin


Item model number


Date First Available

April 1, 2019

3 reviews for Renogy 12V 40A DC to DC On-Board Battery Charger for Flooded, Gel, AGM, and Lithium, Using Multi-Stage Charging in RVs, Commercial Vehicles, Boats,…

  1. Amazon Customer

    If you have a lifepo4 battery bank you understand that charging outside of solar can be a challenge, this unit does accomplish that. I charge a 200 AH lifepo4 battery with it on a pop up trailer that I use for off grid camping for up to two weeks at a time. I was looking for a charger that could be run off my 1800 watt generator or charge from shore but since that does not exist in my price range I found this instead. I chose the 20A version as I do not want to stress my generator too much, and maybe down the road I will tie in my tow vehicles power as well. I used a cheaper 120 volt to 12 volt 30 amp regulated power supply which thus far seems to work well. The only reason I don’t give it 5 stars is that the instructions are complete garbage, after several attempts at the DIP switch settings I contacted reneogy and they instructed me that the switches should be set to S1 off, S2 on, S3 on, S4 on, S5 off for lifepo4. I have only had a couple field trials of this charger thus far and I am not using my vehicle to charge the bank currently so longevity is unknown. The one other thing I don’t like is it pushes my bank slightly higher than my solar setup does which I have set to 14.15 volts, but it is not going to be a primary charger in my case only a shore charger that I use for backup and when solar is not available or impractical (I have to remove my panels).

  2. busyteach

    Received charger and was delayed in getting installed in my RV. The return window had closed before I had a chance to install and test the unit. I could not get the unit to charge after installation even after testing and retesting the installation. I still had no output from the charger even though the green light was on.

    I fnally gave up and contacted Renogy CS and sent a video of my tests, installation, and setup. They sent me an RMA. Once they received the unit, it was tested and they notified me that it worked fine and I would need to pay for return shipping to get it back. After a lot of discussion I did agree to do that but on the conditions that if it did not work, I would want a full refund of all costs involved with the unit and shipping.

    Technicians agreed to review the video I had sent before getting authorization to return and noticed the dip switches were incorrect. I did not believe that was true but rechecked and was still convinced they were correct per the manual. Since they missed that point, they did agree to return the unit without charge. I did see the ON indicator on the bottom side of the dip switches when I inspected closely in good lighting. I had the switches set exactly the opposite since I assumed up was on. With the change, the unit worked just fine.

    If you purchase a unit, make sure you download the latest manual on the website. It has been changed to reflect the position of the dip switches and a few other clarifications. It is still a little vague on the wiring of the run signal and low current input but much improved from the previous manual. Mostly straight forward however. At this point I am pleased and I only subtracted a star for the confusion on the dip switches. I would give support 5 stars for helping me out however.

  3. In the Mountains

    I spent my entire weekend re-wiring my camper to make a spot for this charger and connect everything via #4 wire and custom-made cables. I finally got everything completed and, after all of that work and money, the unit doesn’t work. Doesn’t turn on, doesn’t pass a signal. It’s going back to Amazon.

    I notice another reviewer had an issue with the “on” switch. That could be the problem with my unit, as well, but how would I know with the completely worthless, incomplete instructions that list nothing about the requirements of installing the unit?

    Save yourself the time and expense and skip this thing. Absolutely ridiculous.

Add a review

Your email address will not be published. Required fields are marked *