MPPT Solar Charge Controller for RV and Boat

MPPT Solar Charge Controller for RV

MPPT solar charge controller fot RV

Charge controller for RV and marine solar power systems:
  food trucks

Unlike traditional off-grid solar power systems where there is only one battery bank to manage, in these vehicles we have two different batteries to manage: the auxiliary battery (MAIN) and the starter battery (START).

The auxiliary battery is normally used to power all household appliances and electronic devices on board, while the starter battery has the task of starting the engine and powering the engine control unit and other low-consumption appliances, such as the clock on the dashboard.

Both are charged while we are traveling through the vehicle alternator, but what happens when we stop in the middle of nature with the motorhome or we leave our boat anchored? In these cases the auxiliary battery will be discharged as we use the appliances and the starter battery will suffer small inevitable losses. You will probably already know this, but it is the small and prolonged losses that give rise to the irreversible sulphation process in most lead acid batteries; sulphation which then leads to their premature replacement.

It is therefore clear that if we want a really well-designed solar power system for our motorhome or our boat, we need a special dual battery solar charge controller, a controller that is able to recharge the auxiliary battery in the best way and at the same time keep the starter battery fully charged, even if the vehicle remains stationary for a long time. This is exactly what our solar charge controller does.

dual battery solar charge controller for rv

What types of batteries can be managed and how to select them? As visible from the photo, the controller is equipped, on the right side of its terminal board, with a group of four encapsulated white switches (DIP switch) and a table of combinations. By positioning these four switches it will be possible to select four different types of batteries:

•   Lead-acid (Sealed)
•   Gel
•   AGM
•   the modern LiFePO4 batteries

The battery type we are going to select will be the main battery (MAIN), that is the auxiliary battery. The starter battery (START), on the other hand, will not be indicated because it will only be kept charged and will receive a maximum trickle current of 1A.

What are the best types of batteries for an RV solar power system? Without a doubt, LiFePO4 type (Lithium Iron Phosphate) is nowadays the best choice as an auxiliary battery, while AGM type (with high inrush current) is a very good choice as a motor battery. If a 12V 100Ah LiFePO4 battery (with dedicated BMS) is not enough to meet the energy needs of the passenger compartment, you can add another one, connecting it in parallel. Here is a guide on how to connect two or more batteries in series and parallel.

And regarding the solar panels? Well, this charge controller accepts solar panels with a peak power up to 350W. If you have three 100W panels you can therefore wire them in parallel. Here is a guide on how to wire multiple solar panels in parallel. Don't worry about the number of cells that make up the panels because this controller uses MPPT technology and therefore will use all the power of the panels to charge our 12V battery, regardless of whether the rated voltage of the each solar panel is 12V, 18V or 24V. The outer shell of the MPPT charge regulator is in die-cast aluminum in order to guarantee the best ratio between strength, lightness and heat dissipation capacity. In addition, a fan for air circulation is mounted on its back.


rv solar charge controller

A good RV solar charge controller can't be supplied without some important accessories, right? Well, let's see what they are and their respective function within our system.

The first accessory is the remote digital meter. Thanks to its backlit display you will be able to easily view and monitor all the parameters (battery voltage, charging current, total power, battery capacity, energy) from a passenger compartment point of your choice. The meter comes with 4 fixing screws and a connection cable 5 meters long. In addition, the most tech-savvy users can monitor the progress of the charge even from their Smartphone or iPhone. The controller has in fact a bluetooth antenna and a dedicated app, free of charge, in 8 different languages.

Another important accessory that you will find in the package is the temperature sensor. Fixed on a 3 meter long cable, it must be connected to either one of the two poles of the auxiliary battery. In this way the controller will also take into account the battery temperature during the entire charging process. Reading this information, often absent in the poorer controllers, is essential to guarantee the correct charging voltage. For connection, the inner diameter of the sensor eyelet is 8mm. Finally, you will also have two blade fuses (40A and 5A) that will guarantee maximum protection against any short circuits along the lines and then, of course, you will have the instruction booklet.

Wiring diagram

rv solar panel installation wiring diagram

First, you need to set the type of main battery that the charge controller will have to manage. To do this, just look at the table printed on the controller, find the technology of your auxiliary battery and position the four switches accordingly. Then, the temperature sensor will be fixed on one of the two poles of the battery (or on the side of the battery, as you prefer) and its connector will be connected to the controller port called "Temp. Sensor".

Once we have done these two operations, we can connect the auxiliary battery to the controller through a pair of cables with a section equal to or greater than 6mm² and less than two meters long. I advise you to choose a pair equipped with a fuse holder near the positive terminal of the battery so as to place the 40A fuse supplied. Fuse is optional but recommended because in the event of a short circuit on the line, the fuse will protect the cable from immediate overheating and from the risk of fire. The charge controller, on the other hand, already has internal protection against short circuits. We therefore connect the red cable (+) from the positive pole of the main battery (1) to the controller terminal called "I MAIN" and then the black one (-) to the terminal called "I + II", with electrical grounding to the chassis of our RV or boat.

Since the negative pole of the starter battery will already be connected to the chassis, we just have to take a red cable with 1.5mm²-2.5mm² section and connect the positive pole of the starter battery to the controller terminal called "II START". Also in this case it is recommended to choose a cable with a fuse holder so as to accommodate our 5A fuse and protect the line. Excellent, at this point we can finally prepare to connect the solar panel. Let's cover the panel to avoid the formation of sparks during the wiring. After that, we can connect the panel through a cable with a section equal to or greater than 6mm² to the terminals "+" and "-" of the controller (solar input), paying attention to the polarity. Congratulations, the solar power system is now complete and is ready to give you free, clean, renewable energy for all your RV adventures!

Technical specifications

Maximum PV power 350W
Maximum PV voltage (Voc) 50V
Maximum PV current 21A
Battery type •   Lead-acid
•   Gel
•   AGM
•   LiFePO4
Battery voltage 12V
Maximum current to AUXILIARY BATTERY 25A
Maximum current to STARTER BATTERY 1A
Self-consumption ≤ 4mA
Efficiency > 95%
Bluetooth YES (app in 8 languages)
External material Aluminum
Dimensions 147 x 74 x 40 mm
Weight 400 g


In compliance with European directive 1999/44/EC, the warranty is valid for 2 years on conformity defects from the issuing date of the sales receipt or invoice. If the product does not entirely meet your expectations, you have the right to return it within 14 days and get a full refund. No questions asked.


On average, delivery within the European Union takes 2 to 5 working days. If your delivery address is outside of the European Union, you may be subject to customs charges and delivery may take a few days more. Anyway, you will receive an email notification as soon as the product is shipped.

Payment methods

You can make the purchase using your Paypal account and the most popular credit cards such as Visa, Mastercard and American Express. Click on the "Add to cart" button and choose the method you prefer. If you have any questions about the product, do not hesitate to contact us.

Price:   147,00    

  Out of Stock

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mppt solar charge controller for rv