I'm working on a smart watering system for few flowerpots I have in my balcony. My main problem is that I don't have electricity output there, so I'm trying to think of a way to power my Arduino with 12 V somehow. I thought of using 12 V battery and a solar panel, but since I have indirect sun most of the day, and small solar panels are expensive, I dropped the idea. I hoped for some advice, how can I recharge the batteries without direct connection to my home electricity?
You can make battery powered system. Use 12v battery and buck converter to 5v to save power(instead of using linear voltage regulator which cost much power).
your idea is to make automated watering system>>>> so i suggest you to place water tank in height may be 2 to 3 feet above the pot water level. and use solenoid valve instead of motor pump. and use tip122 to switch ON whenever you want to put water to plants.
are you using any sensor to read water level ? or if your board has more waiting time i suggest you to put your arduino in sleep to save power!!!! use this library here.
In power saving mode using Arduino board does not help you much. you may need to use barebone.
################## if you find difficulties, do one thing if your power plug and balcony is in one digit meter distance, place arduino where you get power. get lengthy wire connect it to switching transistor and valve... Simple...