What I am looking to do is use either my Arduino Diecimila or Mega to control a system where a Solar panel would supply the power to a low wattage DC water proof pump to allow water to circulate in a pond when the sun is out. When it is night time I’d like the battery pack that would have also charged during the day to supply the pump with a lower amount of power so it at least allows the water to circulate at night.
I know I would use a photosensor to allow me to know if it was light out or dark (or over cast) so we can switch over to the battery.
What I am not sure is the following:
Low Wattage DC water proof Pump
What rechargeable batteries I should use, be it quite a few 1.2V standard batteries, or 3.6V 2000mAh batteries which would offer me longer lasting juice.
Looking forward to whatever suggestions and follow up questions people may have.