ELWA: Use solar power only for hot water

ELWA is a 2 kW photovoltaic water heating device. Direct current from photovoltaic modules is transferred directly to the built-in heating element and immediately converted into heat without loss. The built-in MPP Tracker ensures that the PV generator is always operated at the optimum operating point (similar to a PV inverter).
For operation, no connection to the mains is required as the unit is powered by the PV generator (pure off-grid operation). The desired DHW temperature is set with a rotary knob, LED displays inform about the current device status.

Hot water always available, even during bad weather.
Due to the patented boost-backup function, hot water supply can be guaranteed even during bad weather. This makes it possible to completely switch off the conventional heating system in summer. This also increases its lifespan.
For commissioning the boost-backup function, ELWA can be easily connected to a mains socket. There is no feed-in into the grid, so it does not need a metering point like a grid-connected PV system.
![]() | With our my-PV Power-Coach you can easily and quickly get a personal analysis of your system. |
Your advantages with hot water from photovoltaics
Easier and cheaper than thermal solar systems
No grid operator approval required: You save yourself tedious administrative work, because ELWA does not feed electricity into the grid. Especially in multi-storey apartment projects, the approval can take several months for grid-connected PV systems.
Easiest installation with "cables instead of pipes", less valuable copper, no maintenance costs.
Stratification-heating possible with 2 devices.
Even works in case of power failure.
Boost-backup optionally usable.
No anti-freezing liquid necessary
Cables have almost no energy loss compared to pipes
![]() | Further advantages can be found here. |
Accessories

Data evaluation with USB interface
ELWA has an integrated data logger. With the USB interface and the free ELWA software, you can read out your solar yields and see, for example, the temperature increase of your hot water. In addition, device settings can be easily customized for your individual needs.
Remote monitoring with Modbus interface
In case that several devices are to be controlled and monitored from a central location, my-PV has developed a suitable Modbus interface. This solution is particularly suitable for apartment projects. In addition, a further temperature sensor can be integrated into the controller.
Technical data
DC nominal power | 0 - 2000 W with MPP tracking |
DC inputs | 1 string, 100 - 360 VDC, MC4 |
AC boost power | 750 W for boost-backup |
Mains connection | Single-phase, grounded plug, 230 V, 50 - 60 Hz |
Dimensions (WxHxD) | 130 x 190 x 600 mm with heating element |
Protection class | IP 21 |
So that everything runs smoothly with the ELWA
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