Solar Powered Humidity Extractor

In this instructable, I'm going to show you how I realized a system to solve a humidity problem from a storage room in a basement flat using solar energy instead of electricity from the network. At first, for reasons of economy and time, I solved the problem by using the electricity at home. Later I decided to switch to solar power by changing the system from 220V AC to 12V DC. You can find the italian version of this project on my blog officinasottocasa.it

Humidity switch 12V - https://amzn.to/3LicIaf

Lead-acid battery 12V 7.2 Ah - https://amzn.to/3Ag8YRr

20A solar panel voltage regulator - https://amzn.to/3N7g427

Fan 12V 2W - https://amzn.to/3V0HF71

Solar panel 12V 20W - https://amzn.to/40szeCD

The controller is the element to manage the charging of the battery by the solar panel. I have chosen a regulator that is oversized relative to the needs of the project. This guarantees us appropriate underutilization of the component, which, therefore, does not run the risk of producing too much heat.

The voltage regulator has three connections (each with + and -): one for the solar panel, one for the battery, and one for the load.

I chose a 20W panel, presumably sufficient power for the application in this project. To verify the actual sizing would require estimating the consumption of the loads, the average on-time as a function of humidity, panel irradiance, etc. I opted for the experimental method: if the battery will never reach full discharge voltage, it will have been sufficient, otherwise I will increase the panel power.

For the installation of the panel, I used the stand for an old satellite dish. Orientation and tilt are south and 32.6° respectively.

At this link https://www.fotovoltaiconorditalia.it/idee/orientamento-inclinazione-pannelli-fotovoltaici-rendimenti you will find a detailed description of these two parameters for installing a solar panel.

I soldered an SAE connector to the battery and added on the positive terminal a fuse holder with a 3A fuse. This is a redundant safety item since the regulator claims to have all overload/short circuit protection. But caution is never too much and besides I already had the parts, leftover from another little job on my motorcycle.

The humidistat is nothing more than a relay connected to a circuit that opens and closes it according to the humidity values detected by the probe connected to it.

In another project (home thermostat for my heating system) I built a similar device with an Arduino, a relay, a temperature detector, and a clock module.

There is little to say about the fan, other than that once it is connected it starts spinning....

The fan is connected to the output of the humidistat, So it turns on when the humidity rises above the set limit.

To test the operation of all components, I fixed them on a temporary base and left the device on while waiting to see how many days of battery life it has.

As always, with the help of a trusted friend, we installed the device in its final location.

Now the system has been working for a couple of months and has never given any problems.

I monitor its effectiveness with a Zigbee humidity and temperature sensor system.