Looking for a spare battery. The runtime is certainly less than the ad says. I'm finding 5Ah and 2.5Ah. What difference will the Ah rating make?

Keep in mind this is very power intensive it uses more juice than rbe mower. I use the 7.5 battery ans it definatly get the job done. The 5 will do an adequete job

Hi there, good question. The higher the Ah the longer the run time. Thank you for your question.