Fothermo photovoltaic 1kW heating element in boiler and hot water tank

With the 1kW solar heating rod from Fothermo (MPN: ROD-1000), you can easily convert your existing hot water tank to PV. Simply screw the photovoltaic heating rod into the standard 1.5" thread. From now on, you can use solar energy to heat your water and no longer have to rely on expensive gas or oil heaters. It offers you continuously adjustable power control from 0 to 1000W. With the practical surplus function, you can transfer excess electricity to a second heating element or feed it into your own home power grid using a small micro inverter. This allows you to save on your hot water and electricity costs. Another advantage is that you do not need to register, as it does not feed directly into the public power grid.

The advantages at a glance:

• 0-1000W continuously variable heating power
• For hot water tanks up to 500 l
• Patented MPP tracker for maximum yield
• Up to 3000W PV connection power
• Direct DC usage
• Innovative surplus feed-in
• Max. temperature protection
• Supports heating system
• Easy installation – plug & play
• No registration required
• Made in Germany

Hot water heating using solar power

The solar heating rod is a simple and inexpensive solution to support your heating system. You screw it directly into your existing hot water boiler, effectively reducing your energy costs. At the same time, it takes the strain off your heating system or heat pump. The heating rod is ideal for storage tanks up to 500 liters. It has its own temperature sensor and a freely adjustable maximum temperature of 65 °C (or 85 °C for lime-free water). If there is not enough solar energy, the temperature sensor of the heating system ensures that the water is automatically reheated. This means you always have hot water, even in winter.

Use of surplus energy - Thanks to an innovative switchover function, you can make flexible use of surplus photovoltaic power. As soon as the maximum water temperature you have set is reached in the storage tank, the system switches over automatically. This allows you to either use the surplus electricity for additional solar heating rods in a cascade connection or feed it into your own home power grid via a micro PV inverter.

Cascade connection – You can connect two solar heating elements in series. This allows the hot water in the storage tank to be stratified in a particularly energy-efficient manner. As soon as the upper heating element reaches its maximum temperature, the system automatically switches to the lower one, which is located deeper in the storage tank and continues to heat the water there.

Grid feed-in – As soon as the hot water tank has reached its maximum temperature, it can automatically switch to a micro PV inverter. This allows excess solar power to be used easily and without additional bureaucratic effort. This not only reduces the cost of hot water, but also further reduces general electricity costs.

Who is the solar heating rod suitable for?

The solar heating rod was developed specifically for smaller households with 1 to 4 people in order to significantly reduce the cost of hot water. It supplements your existing heating system – whether gas, oil, pellet heating or heat pump – for hot water production.
Example: With just three photovoltaic modules, a 2-person household can generate almost all of its hot water with solar power during the summer months. Over the whole year, the modules supply around 75% of the energy required for hot water production.

Retrofitting via plug & play

Installation is child's play. The photovoltaic heating element is simply screwed into the standard 1.5" flange of your existing hot water tank and the PV modules are connected in parallel using simple plug-and-play MC4 connections. The heating process then starts immediately, and since there is no complicated wiring and the voltage level is below 50 V, no electrician is required for installation.

Display of performance data:

• Voltage - Input voltage of the solar modules
• Power In - Input power of the modules
• Power Out - Output power
• Heating Energy - Energy used for hot water production
• Output Energy - total energy output
• Maximum temperature

Technical data:

• Stepless heating power: 0 - 1000 W
• Max. voltage: 50 V (max. open-circuit voltage)
• Recommended PV module power: 38-43 V (MPP voltage of the PV modules)
• Max. input current: 23 A, automatic current limitation
• Max. connected power: 3000 W
• Recommended connected PV power: 1500 - 2500 W
• Water temperature range: 5°C - 65°C
• Max. output power: 1000 W
• Screw-in diameter: G 1 ½ inch
• Protection class: IP20
• Weight: 0.9 kg
• Heating rod length/immersion depth: 315 mm / 295 mm
• Unheated heating rod length: 50 mm
• Dimensions: 468 x 140 x 154 mm

Scope of delivery

1x solar heating rod 1000 W
1x operating instructions
2x pairs of solar plugs