I'm by far NOT an expert but I never MIX types of rechargeable batteries to Many Things can go wrong IMHO. I charge my Batteries IN the radio, I have it set to cut off in 9 Hrs thats just about how much time I get out of a charge.
Many in here have cringed at charging in the radio, but it works for me and the radio is never warm after 9 hrs.. Just my 2 cents worth
Rick