Topic: Davis 6612 Solar Power for 24-hour FARS

[bgrattan]

Hello,
I have a Davis 6612 Heavy Duty Solar power kit and would like to use it to power my 24-hour FARS fan. I realize this is overkill but I'm not sure my FARS batteries are charging correctly.
Has anyone set this up for the correct voltage? I believe it's 6 volts and should be only 3 volts (?) for the fan. I'm not sure how to do the electronics to lover the voltage.
Thanks in advance for any electronic help on this.
Cheers,
Bob
grattans.org/wx

I have a VP2+ running weewx

[CW2274]

The stock solar panel in full sun generates about 2.45 vdc IIRC.

[johnd]

You would need a DC/DC converter with an input of 6v and an output of say 2v. Relatively cheap to buy and easy to use, but you do perhaps need a small amount of experience in hobby electronics to source a suitable unit and build it into a reliable circuit.

[Garth Bock]

You would need a DC/DC converter with an input of 6v and an output of say 2v. Relatively cheap to buy and easy to use, but you do perhaps need a small amount of experience in hobby electronics to source a suitable unit and build it into a reliable circuit.

It's called a Buck Converter and can be purchased from many sources including Amazon.

[vinceskahan]

You would need a DC/DC converter with an input of 6v and an output of say 2v. Relatively cheap to buy and easy to use, but you do perhaps need a small amount of experience in hobby electronics to source a suitable unit and build it into a reliable circuit.

It's called a Buck Converter and can be purchased from many sources including Amazon.

Like this one ?
https://www.amazon.com/Converter-DROK-Regulator-Inverter-Transformer/dp/B01NALDSJ0

Can you explain how these things work ?  Do you have to tune it or build a circuit on a breadboard to set the in/out voltages or something, or are there a range of such things to pick from ?

[johnd]

I’m no electronics engineer, but i believe the principle is something like a switching power supply. In the ones I’ve seen and used there is a chip at the heart of the converter and then an inductor and capacitor to provide smoothing. For a working converter you obviously need more than the chip itself so be careful what you buy.

They also come in different current ratings. Some are fixed voltage converters and some allow the output voltage to be varied (via a variable resistor i think)

One example:  https://thepihut.com/products/adafruit-lm3671-3-3v-buck-converter-breakout-3-3v-output-600ma-max

But there are many circuit designs and variants out there

[bgrattan]

Thanks, everyone, for your help and suggestions.
Cheers,
Bob