The first year I started using a mechanical system I found out it was much better without charts , because I was not disciplined enough to take all the signals the sys gave me (yes I thought I was smarter than statistic).
Sometimes on a chart the signal seemed so wrong I refused to take it, obviously often those were very good trades.
Today fortunately I understand you have to take all the signals, no matter what!
So if you have a good sys, I think you can use it without charts, quotes are all you need.
On the other hand If your sys is based on chart patterns , you can't trade without charts, but you don't need me to know it.