Are you looking to get more from your off-grid power? Investing in remote energy for your travels or hobbies means investing in reliability, and it’s only with the most intelligent devices that this is possible.
That’s where a high-performance MPPT solar charge controller comes in.
Gone are the days of fearing you’re not getting enough from your solar power system, thanks to MPPT technology. In this guide, we’ll explain what a solar charge controller does, what MPPT is, and which devices to choose from at Onboard Energy.
What Does a Solar Charge Controller Do?
A solar charge controller regulates the current (I) and voltage (V) generated by your solar panels to ensure your leisure battery (or batteries) charges efficiently. The energy your solar panels collect is often too high in voltage for your leisure batteries to handle directly, so the controller’s job is to manage and optimise that energy flow.
What is MPPT and What is it Used For?
MPPT stands for ‘Maximum Power Point Tracking’. This technology uses DC-to-DC conversion to track, in real-time, the point at which voltage and current combine to produce the highest possible power output. The controller manages solar panel performance and leisure battery status to do this.
Typically, this efficiency depends on the time of day, the temperature and any cloud coverage, so an MPPT solar charge controller ensures consistent control of renewable energy, wherever you are.
Solar charge controllers are typically used on systems with one or more solar panels, so they’re suitable for off-grid setups like narrowboats, caravans or other standalone solar setups of varying sizes.
How Does an MPPT Solar Charge Controller Work?
An MPPT solar charge controller's core functions include:
- Maximum Power Point (MPP) tracking of your solar setup by balancing voltage (V) and current (I) to maintain the maximum power output (P = V x I).
- Operating as an intelligent DC-to-DC converter by taking high voltage, low current DC power from the solar panel and converting it into the lower voltage, higher current required to quickly and safely charge your 12V, 24V, 36V, or 48V leisure battery.
- Regulating the converted battery power, the MPPT prevents the battery from being overcharged, extending your leisure battery’s lifespan.
What Are the Voltage Requirements of a Solar Panel for MPPT Charge Controllers?
For an MPPT charge controller to operate at peak efficiency and for your leisure batteries to reach full charge, your solar panel’s operating voltage (Vmp) should be at least 5V to 8V higher than the battery’s absorption voltage.
For instance, a 12V battery has a typical absorption voltage of 14V to 15V, so your solar panel’s Vmp should be a minimum of 20V to 23V.
Important safety note: Connecting multiple panels in series can generate hazardous DC voltage levels, so all installations of this type must be performed by a qualified electrical professional for compliance and safety.
What’s the Difference Between MPPT vs PWM Solar Charge Controllers?
The main difference between MPPT and PWM solar charge controllers is the efficiency, as MPPT controllers deliver up to 30% more power to the battery.
Pulse Width Modulation controllers may be simpler to use and cheaper to buy, and they absolutely have their place in smaller, lower-power systems. However, MPPT technology provides superior performance for more demanding applications.
How Do PWM Charge Controllers Work?
PWM solar charge controllers essentially function like a switch to control battery charging, opening and closing in pulses until the battery is charged. However, your solar panel voltage is pulled away from its optimal operating voltage to match the battery voltage, meaning the battery operates less efficiently than it should.
Although a low-cost option for smaller voltage systems with one or two solar panels to power lights, camping accessories and USB chargers, they’re not as suitable for higher-power systems. PWM panels also need to be connected in parallel, not in series, if there is more than one solar panel.
MPPT vs PWM: Quick Comparison
|
Feature |
MPPT |
PWM |
|
Efficiency |
Up to 30% more power delivered to the battery |
Less efficient power delivery |
|
Function |
DC-to-DC converter that actively tracks MPP |
Pulses power in bursts to the battery |
|
Panel Voltage |
Converts excess voltage into usable amperage |
Pulls panel voltage down to match the battery voltage |
|
Best For |
High-power systems, multiple solar panels, varying weather conditions |
Small, lower-power systems, consistent temperatures, single solar panels, parallel wiring |
What Types of Victron Energy MPPT Solar Charge Controllers Are There?
There are two ranges of Victron MPPT controllers, which include BlueSolar and SmartSolar. When choosing, consider three factors: battery voltage, charge current and maximum PV array voltage.
Both types come in various models and specifications, including:
- Battery voltage (12V, 24V, 36V, 48V)
- Maximum PV array voltage (75V to 250V)
- Charge current ratings (10A to 100A)
|
Range |
Key Feature |
Connectivity |
Ideal For |
|
Reliable, robust base model. |
Requires a separate VE.Direct Bluetooth smart dongle for wireless communication. |
Systems where cost is a primary concern, and remote monitoring is optional. |
|
|
Integrated wireless monitoring. |
Direct connection to the VictronConnect app and compatibility with advanced features. |
Users who prioritise seamless systems, advanced monitoring and system automation. |
As a remote energy solutions provider that matches any price online and an authorised Victron Energy dealer, Onboard Energy offers Victron Energy MPPT solar charge controllers from £44 to £540, depending on the model. You can also explore our solar kits for a complete package for your renewable energy needs.
What Are the Benefits of a Victron Energy MPPT Solar Charge Controller?
Victron Energy solar controllers are among the most efficient on the market, reaching 98% efficiency. Compared with competitors like Renogy, Epever and Morningstar, Victron Energy is an industry leader, having been around since 1975. That’s 50 years of innovation!
Victron Energy MPPT Solar Charge Controllers offer 5 main benefits:
-
Maximised energy harvesting: Maintains solar panels at their optimal operating voltage, leading to faster charge times and more usable energy.
-
Superior performance in tough conditions: Compared to PWM controllers, Victron’s MPPT controllers perform significantly better in partially shaded or varying weather conditions, as they’re faster to adapt to voltage fluctuations.
-
Increased safety and longevity: All Victron controllers are designed to feature natural convection cooling, over-temperature protection and power derating in higher temperatures, which means reliable performance and damage prevention (so you can avoid ‘buying cheap, buying twice’).
-
Higher voltage support: Victron MPPT controllers support up to 250V, depending on the model, allowing you to connect solar panels in series, and reducing complex cabling.
-
Improved connectivity and monitoring: Through built-in or optional Bluetooth and VE.Direct ports, you have complete visibility on real-time data, like battery status and charging history, so you can optimise your setup remotely.
With Victron Energy MPPT solar charge controllers, you get seamless integration into your setup, flexibility in system design, and reliable performance that makes downtime a thing of the past.
What is the Best MPPT Solar Charge Controller?
Ultimately, the best MPPT solar charge controller is the one that suits your requirements most and is within your budget. Investing in a higher-performing piece of equipment is always useful in the long term, as they’re engineered to last, meaning it’s an efficient choice.
Plus, nearly all of the MPPT solar charge controllers we stock at Onboard Energy have 5-year warranties, and will be shipped to you within 24 hours.
How to Install an MPPT Solar Charge Controller
As a complex electrical component for your off-grid system, your MPPT solar charge controller must be installed correctly for safety and performance.
If you’re installing it yourself, you should consider at least 4 factors:
- Install the unit away from direct sunlight.
- Mount the controller less than 5 metres from the leisure battery.
- Use a suitable cable gauge between 10mm² and 16mm².
- Leave at least 10cm of clearance around the unit for natural cooling and airflow.
If you’re unsure about DIY installation and want a professional to help, speak to our Trustpilot ‘Great-rated’ team at Onboard Energy for them to handle your installation with precision.
Ready to Upgrade Your Solar Setup?
Whether you choose the BlueSolar or SmartSolar controller, you’re guaranteed to get the most usable energy and battery protection with a Victron Energy MPPT solar charge controller.
Contact the team at Onboard Energy today to find the best model for your setup or to arrange a professional installation.
Prices are accurate as of November 2025.
