Nexol NEX-R1 Energy Controller & Screw-in Heater for PV and Grid

With the Nexol Screw-In Heater and Energy Controller (MPN: NEX-R1), you can use solar energy directly from your PV modules to heat water in a cost-effective and straightforward way. 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. For optimal efficiency, the heating element should be installed as low as possible in the storage tank. The system also requires no registration or permits, since the electricity generated is not fed into the grid. Ultimately, you’ll 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
• Guaranteed hot water supply
• Legionella prevention program
• Retrofit existing systems—compatible with 1.5" E-sleeve
• Heating support
• Smart touch-screen control
• Easy Installation
• 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 heats the storage tank. In bad weather or when the sun isn’t shining, the Energy Controller can also use grid power for supplemental 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 water heaters. 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.

Hot Water Supply

The system offers flexible settings for different user types. You can customize how often the system reheats the water each day, the maximum temperature to which the water is heated, and the PV output threshold at which reheating begins. 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 process. 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 the temperature exceeded 60°C. If this temperature is not reached, the system automatically activates supplementary heating via the grid.

Quick and Easy Installation

Simply connect the PV modules directly to the Nexol Energy Controller using MC4 connectors. The controller is additionally 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 via a plug. 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: 1
• Max. heating power: 1.5 kW
• Screw-in depth: 350 mm
• Protection rating: IP65
• Screw-in thread: 1.5"
• Unheated area: 100 mm
• Max. tightening torque for threaded connection: 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-R1 Energy Controller
1x Screw-in heating element for PV and the grid