This week I decided to verify that the fans did not impede the opening and closing of the windows before continuing with the build. Shown below is a video of the windows opening and closing without issue.
Testing of the voltage regulator was done quickly using the DMM. A somewhat stable 12V signal was at the output of the voltage regulator with a ripple of 80mV at 93% efficiency. Current and voltage for the regulator are set using a pair of potentiometers near the output terminal of the board.
To verify that the regulator would work as intended, it was wired up to a test version of an intake array using 3 relays, the LD33V for the input to the relays, and as the 3.3V signal to simulate a separate signal from the PICO. It was decided that the LD33V would draw current from the 5V supply of the PWM charge controller due to the excessive heating and power losses associated with the voltage conversion of the LD33V. Testing confirmed that the purported 93% efficiency was accurate and, more importantly, that the fans do not draw 180mA as advertised, but instead draw only 80mA per fan.
Assuming each window uses a similar number of fans and relays, the total power consumption of the current setup will be 22.984W. The relays may present an issue as the current draw per relay is nearly 100mA. That would mean, from the 5V supply on the PWM charge controller, we would be drawing nearly 1.2A just to allow all the fans in our current setup to activate. This week, alternatives will be sought given that the current draw for each of the fans is lower than expected. Transistors will be re-considered given that the relays not only draw a high amount of current, but also require a large amount of space.
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