I never had much luck with the cheep batteries. They are fine as a backup battery in an emergency exit sign but not built for the abuse of a race track. Took most back to the store the first day after they were used at as track. Purchase batteries designed to run TAG. Recommend the 9ah over the 7.2.
A +1 to Jim’s suggestion to go with the Lithium
LAD Specialties customer / tony kart / rotax / kt100