What was the main reason Britain won the Battle of Britain?

I read that the main reason was simply that the English outproduced the Germans in terms of aircraft. The German losses were unsustainable after some weeks and that's why they decide to withdraw the massive Luftwaffe attacks on Britain.

Is that - in short - the main reason? I know about radar and stuff but that was just one minor factor.

Another related question: How could the Germans have won the battle of britain? I'm only talking about the aerial war here. I know that they couldn't have invaded Britain mainly due to the Royal Navy.

Looking forward to your inputs.