What device can I use to activate my water heater when I have solar power excess?

Hardware
1

Hello,

Im looking into options to activate my water heat pump when I have excess PV but Im not sure how to achieve it. Im not really familiar with electrical stuff.

It is a heat pump ( Daikin EKHHE200CV3) which is already programed to be on during the day, but additionally it has the capacity to raise the water above it’s normal setting as a means to extract excess PV into hot water. The manual says:

Digital input for photovoltaic. In case of a photovoltaic system connected to the plant, it can be used to subtract energy in the form of hot water in times of over- production. If there is a voltage-free contact, e.g. from the inverter, which closes when there is overproduction of energy, it can be connected to the two green and yellow wires of the 6-core cable supplied with the equipment.

Unfortunately, my inverter does not provide such a contact directly, but I thought I could plug some appliance and trigger it from HA (I have my power monitored through this plugin)

so, what kind of device I can use as a dry-contact to active my heat pump and trigger it from HA? I would appreciate if it was an off-the-shelf thing since I am not familiar with fancy things like ESP

2

Shelly 1 has voltage free (dry) contact.

1 Like
3

thanks. I’ll look into it

4

An interesting approach worth following.

A simple mechanical relay connectet to the green and yellow wire should work.
Operating the relay could be done with a dedicated Relais Power Switch Board.

5

update…
I did install a shelly 1 and so far it has worked great. I set an automation that triggers every 15m and checks if I have a surplus of at least 500w of solar power. if so, I turn on the switch, if I consuming more than generating, I turn it off.