Is a current controller needed for a low Watt charge circuit?
Here's the simple outline for the project, it's a solar charged outdoor light. I'm using an Arduino Nano, 9v rechargeable, a photoresistor, a few LEDs, and obviously a solar panel.
The panel is a 9v 1w panel, so only 111mA, the full sequence is only pulling 65-90mA of current depending on operation, only 40mA during the day when it's basically in idle.
The problem is the entire project costs about $12 in parts at the moment so I'm having a hard time justifying another $10-$15 for a current controller to keep form over charging the battery, especially since only about 60mA of current will actually be going into the battery.
What is the likelihood of damaging the battery if I just hook the solar cell and battery up in parallel to the Arduino?
The programming and hardware design is already done, only thing left is how to charge the battery, straight from the solar panel or through a regulated charge circuit? Obviously the charge circuit is the safest option, but is it really necessary?