Curious what sort of Sikaflex you used on the roof?
BTW, I think you will be disappointed with the solar panel/battery setup.
That's a very small panel, and the battery isn't real big either.
If you want a battery to last, you shouldn't really discharge it below 75%.
If you have a couple of 3W interior LED lights, they are going to pull 0.5 amps between them.
That's about 6 or 7 hours running from that battery, less if you charge a couple of phones or run a ventilation fan while you are at it, before you start to worry you are killing it.
An exterior light, say 10W, call it max 4 hours.
Then a 10w panel will struggle to replace what is used.
If you can manage it, you should get a bigger panel, a regulator and a bigger battery.
I look at a 10W panel as a battery maintainer, something you stick on your car battery to stop the clock and computer from draining the battery while you go away for a month.