

🔌 Charge smarter, travel farther—never get left powerless again!
The Renogy 12V 40A DC to DC On-Board Battery Charger delivers efficient multi-stage charging compatible with Flooded, Gel, AGM, and Lithium batteries. Designed for RVs, boats, and commercial vehicles, it features advanced safety protections and smart starter battery management in a compact, durable form factor.










| ASIN | B07Q4SVX3M |
| Best Sellers Rank | #4,110 in Automotive ( See Top 100 in Automotive ) #1,318 in Automobile Accessories |
| Brand | Renogy |
| Customer Reviews | 4.2 4.2 out of 5 stars (985) |
| Date First Available | 24 April 2019 |
| Exterior | Painted |
| Item Weight | 2.4 Kilograms |
| Item model number | 40A |
| Manufacturer | Renogy |
| Manufacturer Part Number | RNG-DCC |
| Model | 40A DC to DC On-board Battery Charger |
| Product Dimensions | 17.53 x 26.16 x 6.86 cm; 2.4 kg |
B**E
I like the product
Was delivered on time and worked as charm. I liked it.
M**P
Low efficiency.
Working as advertised but found out it’s low efficiency - while delivering 57A it takes 89A from alternator. Also there is no low voltage shut down so when car slow and stop on red light and RPM are low voltage drop below 11V and car (radio lights) not functioning correctly while it still sucks all these Amps.
D**D
All good
M**V
I use this in my overlanding setup. I have a 24v system in my Toyota landcruiser and I needed somthing to connect from my 24v to 12v converter to charge an auxiliary battery. In my situation, my alternator puts out 24v, that will fry this thing. So! I wired it to the output of my converter (12v out). I asked the question before buying this and everyone said 'no it won't work'. I bought it anyway cuz my options were limited. Well, it works. My aux battery has been staying charged while I drive and my fridge freezer has been staying cold. Mission accomplished.
T**A
Equipo electrónico que cumple lo que ofrece con calidad, estoy satisfecho con la compra
A**N
This charger is for my pickup bed/camper and charges a lithium battery. The power supply is isolated from the starter battery. This charger is set up to isolate itself from the starter battery. I didn’t read carefully about the two wires that appeared to be optional. They’re described in the manual and one is required. When the charger wouldn’t charge and I read instructions more carefully, I discovered the unit required connection with one of those little wires to a power source only on when the ignition was on. I made a wire, plugged it in the appropriate slot (requires a very small blade screwdriver) and connected it to the already isolated positive power wire input to the charger. Started the engine and the battery said it was charging at 20 amps. Perfect! The second little wire allows you to charge at 10 amps. I’m adding rocker switches to these wires so I can turn them on or off easily. There is a warning about using this charger around flammable fumes so I want to easily turn it off when hauling fuel.
G**S
Producto de buena Calidad es de gran apoyo ya que aparte de cargar tu batería externa si estas usando en ese momento el inversor suministra los 40 amperes adicionales al inversor por lo que no salen de la bateria dicha corriente por lo que mantiene tu batería cargada más tiempo a diferencia si estuviera apagado dicho cargador. 30/Octubre/2024 Instale el segundo Cargador 40 Amperes funcionando al 100% estoy muy satisfecho con la compra. Con los dos cargadores tengo las opciones de realizar cargas de 20/40/60/80 amperes a las baterías de litio. 08/Abril/2025 solamente hice algunas modificaciones modifique el disyuntor de salida a 100 amperes hacia las baterías de litio y modifique el cable de las baterías del camion a los inversores de 4awg a 2awg para tener menos perdidas de corriente y calentamiento note una mejoría están suministrando 100amperes de consumo por los 2 inversores de momento están funcionando al 100%. En pocas palabras entran 100amperes a los inversores y sacan 78 amperes a las baterias de litio.
Trustpilot
3 weeks ago
1 month ago