MECHANIC REMOVED AND INADVERTENTLY REPLACED A B737-300 ACFT MAIN BATTERY WITH A BATTERY FOR A B737-700.

Narrative

I WAS HELPING AN AVIONICS CO-WORKER ON A B737-300 TO REPLACE ACFT MAIN BATTERY. WHILE I WAS BUSY IN THE ACFT ELECTRICAL COMPARTMENT REMOVING THE OLD BATTERY; MY CO-WORKERS WENT TO THE COMPANY'S PARTS STORE WHERE HE WAS ISSUED A PRE-DRAWN BATTERY AND THEN BROUGHT IT TO ME WHERE I INSTALLED IT (A PRE-DRAWN PART IS A PART THAT WAS PREVIOUSLY ASSIGNED FOR A PARTICULAR ACFT WHEN A COMPONENT IS SCHEDULED FOR A TIME CHANGE). I ACCOMPLISHED THE INSTALLATION AND OPS TEST AS PER MAINT MANUAL; 'OPS CHKED GOOD.' 2 DAYS LATER AT AN ARPT GATE; A PLT RPTED LOW BATTERY VOLTAGE ON ACFT. AN AIRLINE TECHNICIAN DETERMINED THAT THE GATE'S PWR UNIT WAS BAD AND REPLACED THE MAIN BATTERY. UPON EXAMINING THE REMOVED BATTERY; HE DISCOVERED THAT IT WAS THE WRONG BATTERY INSTALLED AND IT BELONGS TO A B737-700. CONTRIBUTING FACTORS: 1) FAILURE ON MY PART TO VERIFY OR RECOGNIZE THE WRONG PART NUMBER. 2) STORES ISSUING WRONG PRE-DRAWN PART FOR THE WRONG ACFT. 3) AN EXPERIENCED CO-WORKER FAILED TO RECOGNIZE THE WRONG PART NUMBER. 4) COMPANY PARTS COMPATIBILITY SYS FAILED TO FILTER THE WRONG PART NUMBER WHEN I ENTERED THE LOG PAGE INTO THE SYS. CORRECTIVE ACTION: REMOVAL AND REPLACEMENT OF THE WRONG BATTERY. FILED AN ASRS RPT. PERCEPTION: I THOUGHT THAT I INSTALLED THE CORRECT PART AND FAILED TO DOUBLECHK THE BATTERY PART NUMBER BECAUSE I RELIED ON STORES AND MY EXPERIENCED AVIONICS CO-WORKER TO DO THE RIGHT THING.