My teammate used a lipo this week, and had no issues all day long. The warmers were used for 30-45 minutes before each race, and the warmers performed flawlessly. The warmers will perform their best when hooked up directly to a 12V supply. The other nice feature about using the lipo is you can go from 12v to lipo, and take your warmers trackside.
Retired from RC....
Quantum - St. Croix - Bass Pro Shops - XPS - Rapala