B737-700 RECEIVED INACCURATE V-SPDS FROM DISPATCH AFTER THE ACFT'S PORTABLE PERFORMANCE COMPUTER FAILED. INACCURATE SPDS CAUSED AN EARLY ROTATION TKOF.

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OUR OPC WAS NOT CHARGING IN THE CRADLE; SO WHEN WE GOT OUR LOAD SHEET; THE COMPUTER INDICATED ONLY 1 BAR OF BATTERY PWR LEFT. IT THEN SEEMED TO 'LOCK UP;' APPARENTLY DUE TO THE LOW BATTERY. WE HAD A WHEELS UP TIME 6-8 MINS LATER. I RATIONALIZED THAT SINCE WE COULD CHARGE THE BATTERY QUICKLY; OUR OPC REALLY WAS NOT INOP AND; THEREFORE; DID NOT NEED TO BE MEL'ED. I CALLED DISPATCH THROUGH OPS AND GOT OUR TKOF DATA SO WE COULD STILL MAKE OUR TKOF WINDOW. DISPATCH CALCULATED OUR V1; VR; AND V2 OF 113; 113; AND 119. TAXIING OUT; I REMARKED TO MY FO THAT THOSE NUMBERS SEEMED A LITTLE LOW FOR A 140000 LB TKOF; BUT THEN I REMEMBERED I HAD FELT THAT WAY BEFORE ON THE -700 WITH WINGLETS AND THE NUMBERS HAD ALWAYS BEEN GOOD. TKOF ROLL WAS NORMAL; AND I BEGAN ROTATION AT 113 KTS. WHEN THE ACFT GOT 10 DEGS ACFT NOSE UP; I NOTICED THAT IT DID NOT FEEL LIKE A NORMAL TKOF; IE; GETTING LIGHT ON THE MAIN GEAR AND ABOUT TO FLY. I REMEMBERED THAT IN THE -300 A PITCH ATTITUDE OF 11 DEG ANNUNCIATION COULD RESULT IN A TAIL STRIKE. MY GUESS IS THAT NUMBER IS PROBABLY A LITTLE HIGHER IN THE -700; BUT I DECIDED TO STOP THE ROTATION AT 10 DEGS ANNUNCIATION; AS WE STILL HAD PROBABLY 3000-4000 FT OF RWY. WE ROLLED DOWN THE RWY AT 10 DEGS ANNUNCIATION FOR ANOTHER 1000-1500 FT UNTIL THE ACFT LIFTED OFF; AT WHICH TIME I CONTINUED THE ROTATION TO 15 DEGS ANNUNCIATION. I RETRACTED FLAPS ON SCHEDULE AND THE REST OF THE TKOF WAS UNEVENTFUL. I WAS SKEPTICAL OF OUR TKOF DATA; SO ENRTE WE FIDDLED WITH THE OPC AND GOT A GOOD CHARGE. WE THEN COMPUTED OUR TKOF SPDS OF V1; VR; AND V2 OF 125; 135; AND 139. YIKES! SEEMS I ROTATED ABOUT 22 KTS EARLY! I HAVE OBTAINED DATA OVER THE RADIO WITH DISPATCH MANY TIMES. OBVIOUSLY THIS TIME WE HAD SOME SORT OF COM PROB; MADE WORSE BY MY 'HURRY UP WE GOTTA FLOW TIME.' I USED TO USE A QUICK CHK TO GET A BALLPARK FIGURE IN THE -300. SEEMS I DROPPED THAT BY THE WAYSIDE SOMEWHERE. IT CERTAINLY WOULD HAVE BEEN A WELCOME CATCH TODAY. ZERO FUEL WT +25 = V2 GIVE OR TAKE A FEW? THE RUSH TO MAKE OUR TKOF TIME WAS INCREDIBLY MYOPIC IN HINDSIGHT. NEXT TIME I HAVE DOUBTS OR SOMETHING DOESN'T FEEL RIGHT; I'LL TRY AND SLOW DOWN AND DOUBLECHK.