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80L photovoltaic off-grid boiler

599,00 €
inkl. MwSt. zzgl. Versand
| /

The photovoltaic boiler offers the ideal solution for a cost-effective and independent hot water supply. Once installed, the boiler will produce free hot water for years.

The 80 liter boiler is ideal for an energy-conscious 2-person household. There it can serve as a replacement for a classic electric boiler or as drinking water preheating for instantaneous water heaters, oil or gas heating systems. The 80 liter boiler is also used in holiday homes and garden or mountain huts.

The product in focus

  • heating capacity

    Up to 550W Heat output.

  • 8 hours

    Time that the photovoltaic boiler needs to heat the water from 20°C to 65°C at full heating power.

  • 80 liters Volume

    Up to 180 liters Use hot water at 34°C water temperature.

  • Renewable

    Renewable provision of heat through the power of the sun.


The installation of the photovoltaic modules is very easy thanks to plug & play connections. The modules are plugged directly into the boiler using standard plug contacts (MC4). An extension cable can optionally be used to bridge larger distances between the photovoltaic modules and the boiler. (Photovoltaic modules and extension cables are not included in the scope of delivery, these can be purchased separately in the online shop.)


In the event that the sun cannot provide enough energy to heat the water for a long period of time, the boiler can be automatically reheated using the optional 230V reheating device. To activate after-heating, a minimum temperature can be set on the boiler. This could be 35°C, for example. As soon as the temperature of the water falls below the set minimum temperature, the water is reheated using electricity from the network. During the post-heating phase, existing photovoltaic energy is also converted into heat. The reheating process ends automatically as soon as the water has reached the set minimum temperature again. fothermo recommends the 240W power pack for the 80 liter boiler to keep the post-heating time as short as possible. (The post-heater is not included.)

The maximum water temperature of the boiler is 65°C. When the boiler is completely heated, around 180 liters of 34-degree water can be drawn from it. As a rule of thumb, around 80 liters of hot water are available every day. Either only by the power of the sun or with the support of the optional 230V after-heating device.

Technical specifications

  • digital display

    Get an overview of the current performance and current energy savings at any time.

  • easy installation

    Plug & Play - We guarantee you an uncomplicated connection of the photovoltaic modules.

  • MPP tracker

    Integrated MPP tracker for maximum solar yield.

  • Further information

    Further information, product specifications, declaration of conformity, manufacturer's instructions, assembly videos and circuit diagrams can be found in our product data sheet (see above) .

Data sheet German
Datasheet English
operation manual
Which and how many photovoltaic modules?

scope of delivery

1x 80 liter photovoltaic boiler
1x user manual
1x pressure relief and check valve


Which photovoltaic modules can I connect to the boiler?

All photovoltaic modules with an open-circuit voltage Uoc of less than 42.4V can be connected to the photovoltaic boiler. These are usually all 60 or 120 cell photovoltaic modules. Suitable photovoltaic modules can be purchased in the online shop.