I have used plugs covered with Shoe Goo to help seal a tire before.
also I have a friend that carries an expanding plug kit. www.stopngo.com/collections/cars he has the deluxe kit in a hard case
good luck with your search.
My daughter has a small electric remote start generator enclosed in her back yard. It is in a well ventilated storage box
she consistently forgets to charge the battery so I want to put a solar panel on it.
it sets in direct sunlight most of the day.
It uses a 12v 6.5AH 10HR Battery for cranking...