Solar panel to charge a 9V for Arduino usage

Other Hardware Motors, Mechanics, Power and CNC
1

Hello everyone-

I have an arduino that is going to be used near a window, and I wanted to find a way to hook up a solar cell to a 9V battery, so that during the day, the arduino has power, and at night it just rests without discharging. Is this something that would be easy to do? I have a 170mAh NiMH 9V, and a 9V, 1.5W, 167mA solar panel from radio shack (item number 2770053). Is there any tricky wiring to get this to work? And how do I prevent the battery from discharging into the solar cell during the night? Any help would be greatly appreciated. Thanks!

2

A diode will allow the PV to charge the battery and will block discharge. Choose one with low forward drop. Here's a good article on 9V NiMH charger: Standard LM317 Charger for 9V NiMh Batteries | Headphone Reviews and Discussion - Head-Fi.org
You may find that your panel doesn't supply enough voltage to use this circuit to charge your battery. A simpler (cruder) method might work, at some risk of reduced battery life.
(You could use a resistor divider and program your Arduino to be a "smart" battery charger!)