FUTABA 10J Charger

I have made up my mind to modify an ordinary AC adapter to meet with FUTABA 10J transmitter driven with 4 pencil type Nickel Metal Hydride batteries 4,8V. It has the capability to supply 12.35 V DC/700 mA, most of the case, 2 or 4 diodes for rectifying and 3 terminal regulator or Steiner diode and resistors for voltage regulation are included inside, but too much high voltage and current, so any modification were required to charge series connected NMH batteries safe, partial current flow and partial voltage pressure should be invited, shortening the circuitry with 17,7 orm/5W resistor guides 300mA and 10 orm /5W resistor parallel connection does 5,3V promptly.  Relatively quick charging method as this setting is, this kind of modification is worth applying to protect the battery while charging. Also, Mechanical Off Timer would be helpful to count the charging period.