Why does my compressor take so long to get up to maximum pressure?

cladoo  you did not tell us what you have checked and what exact model your compressor is. I know you picked the device but we just have to be sure. Usually, if an air compressor is taking long to the fill it typically is either a seal problem, gasket failure, or an intake or pressure valve failing. Your “after a couple of cycles the compressor won’t start again “ could also be indicative of an electrical air compressor that is laboring to fill. That could be an issue with the motor/capacitor. If you have a bad run capacitor it would then no longer start. Start by checking on those things and let us know what you find.