Solar charged battery for jon boat trolling motor

I setup the 10 Watt solar panel on top of the battery box loose just for testing the idea. I use a 10 Amp PWM solar charge controller and a 20Ah battery. The setup has been working so great that I decided to mount the solar panel and the solar charge controller to the battery box and to clean up all the wiring. I plan to replace the cheap Chinese hardware with stainless steel (the hardware store was closed) and fix up the wiring. The rule of thumb when needing a solar controller is 2 watts or less of solar panel per 50 Amp-hour of Battery capacity. If you don't use a solar controller you will need to install a diode to keep the solar panel from draining the battery at night.