running radio on LARGE batteries 6V 3.0 AH $9.95 N.I.B.
 

An ad in the classified section in my November 5 Popular Science
magazine says,Powertool Battery Re-Cell.Send us your dead
batteries,enclose a check/money order,we rebuild and send back in two
weeks.Any brand,12-18 volt,$35 each.Longer run - time!!
www.voltmanbatteries.com 320 N. Mulberry St.Mansfield,Ohio 44902
(419) 526-1570

It might be they will rebuild other kinds of special batteries too
instead of only power tool batteries.They provide their website and
snail mail address and phone number.
cuhulin