Oncore Solar STL 2 months ago ID: #505925 Listed In : Solar Products Saint Louis, MO, 63114 United States (618) 570-1211 https://davidbeckley.oncoresolar.com/ [email protected] Business Description At Oncore Solar STL, our guarantee is the best in the industry. We are the only solar panel installation company that 100% guarantee the amount of energy that your solar power system produces. Contact us today to get started! Reviews & Ratings Write a Review No Review. Please login / register to add your review.