Does anyone have any experience with the factory solar charger? I was hoping that it would keep my coach batteries charged during winter storage but it doesn't seem very dependable.
My RV isn't a Winnebago, but my original RED LED (for my 5 watt solar panel) indicator was in series with the house batteries which means the brightness of the LED could change a bit with the state of the house battery's charge (form other charging sources), regardless of amount of sunlight as long as there was some. IOW, the HIGHER the voltage of the battery, the LESS the LED would light, since there was then less current.
I totally changed my RED series LED to a green LED in parallel (with a dropping resister) direct across 65 watts of new solar panels. Now the LED shows how the solar is working and my new solar controller shows the exact battery voltage in a digital display.
Like others say here, your ten watt solar was twice as good as my five watt which did nothing. Double a nothing and you still have nothing. But somehow, when you go at least five times more, you start to have a little charging during the sunlight hours that can make some difference.

-Don- SSF, CA