Control of solar hot water tanks

Solar domestic water heaters usually work very well.
However, rainy days cannot generate heat, and very cloudy days provide very little heat.
For this reason, a heating resistance is added.
The most economical systems have a fixed operation, meaning that the water is always hot.
The vast majority of homes do not use hot water until midday, and have the highest consumption in the afternoon/night, that is, during and after the point of maximum energy.
It makes no sense to heat and keep the water hot all night for example, because when the sun comes the water no longer needs to be heated.
The equipment incorporates at a very low cost an intelligent system based on profiles so that the water is hot when the user needs it, and that only the minimum electricity necessary for comfort is consumed.

This device has 4 predefined modes, but the user can create their own.

Built in a watertight cabinet for safety