Nexol NEX-R2 3KW Energy Controller & 2x screw-in heating elements for PV and mains

The Nexol Energy Controller and the two screw-in heating elements (MPN: NEX-R2) provide maximum, cost-effective comfort by using solar energy from your PV modules to heat water. Supplementary heating from the grid also ensures that you always have a reliable hot water supply, even when PV output is low. The controller automatically switches between PV and grid power as needed. Thanks to the control parameters for temperature, PV input power, and heating cycles, the system can be precisely tailored to your individual usage patterns. Thanks to the innovative two-zone heating system, the upper section of the tank is heated first, which significantly reduces the heating time. Compared to the NEX-R1, this means hot water is available to you more quickly. The system also requires no registration or permits, since the electricity generated is not fed into the grid. Ultimately, you benefit from low investment costs, as cables are installed instead of pipes.

Your Benefits and Highlights

• Hot water production using solar power
• Heating capacity of 1500W
• Two-zone heating
• Guaranteed hot water supply
• Legionella prevention program
• Retrofitting existing systems—compatible with 1.5" E-sleeve
• Heating support
• Smart touch-screen control
• Flexible Applications
• Easy installation—delivered ready to plug in
• Plug & Play

How It Works in Detail

As soon as the sun shines, the PV modules generate electrical voltage and current flows through the Nexol Energy Controller. There, the current is routed with minimal loss to the DC coil of the AC/DC screw-in heating element, which immediately begins converting the energy into heat and heating the storage tank. In bad weather or when the sun isn’t shining, the Energy Controller can also use grid power for supplementary heating.

Why It’s Worth It

Depending on the energy source, there are varying savings potentials. However, these can be clearly illustrated using the following key figures:

50% – Energy cost savings compared to gas boilers. That means up to €150 in savings per year.
75% – Energy cost savings compared to electric boilers. That’s up to €300 in savings per year.
90% – Use over 90% of the solar power you generate yourself—maximum efficiency and savings for you.

Two-Zone Heating

The system first heats the upper zone of the tank to up to 65°C, enabling a quick supply of hot water. When there is little sunlight, the intelligent system takes over reheating via the grid, focusing on the upper zone to minimize electricity consumption. As soon as this zone reaches its target temperature, the system switches its focus to the lower threaded heating element to heat the entire tank’s contents. This ensures that the energy generated by the PV panel is efficiently stored in the water.

Hot Water Supply

The system offers flexible settings for different user types. You can individually specify how often per day the water is reheated, up to what temperature it is heated, and at what PV output this occurs. If the maximum number of reheating cycles has not yet been reached, the temperature falls below the guaranteed level, and the incoming solar panel output is too low, the grid takes over the reheating. This way, you always have full control and can be sure you’ll always have enough hot water available.

Legionella Program

To kill Legionella bacteria, the water in the tank must be heated regularly to at least 60°C. A program is activated by default for this purpose. The interval between heating cycles can be flexibly set to 1–14 days, with a default interval of 7 days. The Energy Controller starts each interval based on the last time a temperature above 60°C was reached.

Quick and Easy Installation

Simply connect the PV modules directly to the Nexol Energy Controller using MC4 connectors. The controller is also powered via a standard AC plug. After installation, the screw-in heating elements in the hot water tank can be easily connected to the controller using plugs. This way, you’ll enjoy cost-effective hot water in no time.

Technical Specifications

Energy Controller

• Display: 2.8" color touchscreen
• Ambient temperature range: 5°C – 40°C
• Humidity: 10–95% (non-condensing)
• Permissible pollution class: 1
• Protection rating: IP21
• Weight: 2.4 kg
• Dimensions: 339 x 177 x 104 mm

Heating element

• Number of elements: 2
• Max. heating power: 1.5 kW
• Screw-in depth: 350 mm
• Protection rating: IP65
• Thread size: 1.5"
• Unheated area: 100 mm
• Max. tightening torque for screw-in thread: Brass/60 Nm
• Wrench size: 60 m
• Max. operating pressure: 1 MPa = 10 bar
• Dimensions: 89 x 89 x 500 mm
• Electrically insulated

Photovoltaic Specifications

• Recommended installed PV capacity: 2.5 kW
• Max. usable power: 1.5 kW
• Min. PV nominal voltage: 100 V
• Max. PV open-circuit voltage: 300 V
• Max. PV short-circuit current: 15 A
• PV Connections: MC4
• MPP tracking included

Grid connection (optional)

• Power: 1.5 kW
• Input voltage: 230 V
• Input frequency: 50–60 Hz
• Fuse rating: 10–16 A

Package Contents:

1x Nexol NEX-R2 Energy Controller
2x Screw-in heating elements for PV and grid