I used to fly a sail plane with a conquest FP-T4NBF that's been in my closet for maybe 10 years? seldom used.Now that i have the time i want to get into glow planes.I'm looking at the ARF Avistar,to cut costs ,it is safe to put that old batteries in the Avistar.I Just charged them and seen fine to me.If not, what would match my TX and receiver batteries. Thank you.