I have recently completed building an Arduino UNO R3 based, weather station, powered by a 240 vac > 9 vdc transformer, my next stage is to make it Battery Powered with a rechargeable battery, re charged by a Solar Panel.
The My battery is a 12 volt, AGM, Lead Acid type. My PV panel is 12 vdc - 10 Watt, which on a good day gives out around 18 vdc, therefore i have obtained a Battery Charging Controller, 12vdc - 3 amp.
My question is this, as the Arduino recommended safe voltage is 9 vdc, what is the best way, and using what equipment, parts etc; do i need to reduce the voltage on the Load side of the Charge controller to say 9 vdc. suitable for the Arduino ?
I have surfed Google for hours, and there seems to be several ways to do this, though not being an Electrical person myself, i thought i would seek guidance from someone who can put me in the right direction to achieve my aim.