All ego batteries are 56v are you working with a 5.0 or 7.5 battery. 30 minutes is certainly within the specs for the 5.0 using High and low speed.
Approximate Run Time
(with EGO BA2800 56V Battery 5.0 Ah)
15 min. (Boost)
22 min. (High speed)
120 min. (Low speed)