MAULE AEROSPACE TECHNOLOGY, INC.
MAINTENANCE MANUAL
FOR
MT-7-235
Rev. D
31/37
This battery is considered fully charged at a hydrometer specific gravity reading of 1.265.
A low charge would be 1.225 or lower. Operating with a low charge will shorten the life of the
battery and can be prevented by recharging or operating with the electrical equipment turned off
until the battery has been sufficiently recharged.
Some batteries are sealed recombinant design which do not require the external vent tube.
ALTERNATOR AND ALTERNATOR CONTROL SYSTEM
To protect the alternator and battery from an overcharge, the voltage regulator should be
checked for a charging voltage of 13.7 to a maximum of 14.0 volts with the engine at rpm of
1000 or above.
Overvoltage protection is incorporated into the alternator control unit which will latch off
regulator output after an overvoltage event. Reset of latch off caused by either over voltage or
shorted output is accomplished by momentary turn off of supply voltage, i.e., push ALT switch
OFF then ON.
Battery charging is monitored by reference to the ammeter located in the instrument panel
on the right side of the engine instrument cluster. Should the ammeter indicate a minus deflec-
tion when engine is above 1000 rpm and/or red “ALTERNATOR OFF WARNING” light is illumi-
nated, push ALT the switch OFF then ON. Repeat two times as necessary to reset. If system
will not reset, investigate electrical malfunction as operation will be on the battery only.
