A FAIRCHILD F-27 ON APCH AT 6000' DELCARED AN EMERGENCY AND LANDED WITH NO D.C. ELECTRICAL PWR CAUSED BY A BATTERY OVERHEAT WARNING LIGHT.

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BATTERY OVERHEAT LIGHT ILLUMINATED AND EMERGENCY CHECKLIST CALLED D/C PWR OFF. THIS WE FELT WAS AMBIGUOUS. WE SHUT OFF THE BATTERY + THE GENERATORS BECAUSE WE FELT WE NEEDED COMMUNICATIONS. ALL OF THIS LEAD TO EMERGENCY GEAR DOWN AND A FEARLESS LNDG. WE CALLED FOR THE FIRE TRUCKS TO BE ROLLED JUST IN CASE. THE LNDG WAS UNEVENTFUL AND THE PASSENGERS WERE OFFLOADED AT THE GATE. AS A RESULT; OUR COMPANY IS GOING TO CHANGE THE CHECKLIST TO READ MORE CLEARLY. THE PROPER ACTION IN THIS CASE WOULD HAVE BEEN TO SIMPLY SWITCH OFF THE BATTERY; HOWEVER THE CHECKLIST CALLED FOR 'D/C PWR OFF'. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE BATTERY OVERHEAT LIGHT CAME ON DURNING OUR DESCENT FOR APCH. THE RPTR SAID A QUICK CHECK OF THE OPERATING MANUAL FOR BATTERY OVERHEAT WARNING STATED 'D.C. PWR OFF' NO OTHER STEPS OR PROCEDURES. THE RPTR SAID THIS REQUIRED SWITHCING OFF TWO PERFECTLY OPERATING ENGINE DRIVEN GENERATORS AND THE BATTERY. THE RPTR STATED THE SOURCE OF EMERGENCY PWR IS THE BATTERY WHICH WAS SWITCHED OFF. THE RPTR SAID LAS WAS ADVISED TO ROLL THE TRUCKS AS WE WERE LNDG WITHOUT ELECTRICAL PWR AND THEN SWITCHED D.C. PWR OFF. THE RPTR CLAIMS THIS MANUAL NEEDS REVISION BUT SO FAR NO ACTION BY THE COMPANY AND THE FAA ADVISED TAKING CARE OF IT IN HOUSE.