Cordless rotary SDS hammers
If hard concrete is what you're dealing with, a rotary hammer is what you need. Unlike normal hammer drills that produce small percussive motions, rotary hammers’ air-powered piston delivers high energy shots to the rotating bit.

20V 2.0J Rotary Hammer Drill - Balanced in size and power
20V Powershare 4700bpm 2.0J Cordless Brushless Rotary Hammer Drill - Tool Only - WX381.9

3 tools in 1, SDS Plus, 1.2 Joule shot energy
20V 5000bpm 1.2J H3 Cordless Rotary Hammer Drill - Tool Only - WX390.9