I am looking for something battery powered. Something just to have fun with when traveling or a low key back yard jam. Budget is around $500. 
Any ideas? 
  Best deal is Korg new i3 599$.
Better than ek 50 because more control ( you can individually mute acc tracks, not just “ all acc tracks” like Ek. More live control. 16 tr seq, etc)
Pa80 board (Triton classic 32 Mb ROM )even though 20 years old, samples are still relevant for live play)better sounds than any sub 800$ arrangers.