battery?

[captainclutchkick]

i have a 90 240sx with a 97 rb25det from a nissan skyline and im using a smaller 12v battery since space is limited, my car has sat for a few weeks and the battery went dead in the cold, i charged it to 11.5 volts and put it back in and the car would not start, so i jumped it. on the gauge it said the battery was at 14.4 volts while the car was running so i drove it around the block, if i reved the car over about 4000 rpm the battery would drop down under 10 volts and the car would almost die until i let off the gas and the voltage went back up. is my battery bad and will not hold a charge?

[180fan]

discharging a battery all the way is pretty bad. If you're gonna leave your car sitting for more than a week, I'd suggest pulling the - terminal.

[yokota180sx]

your alternator is bad

[captainclutchkick]

i dont think its the alternator becuase the battery was at 12 volts when i put it in and then went to 14.5 when the car was running.

[yokota180sx]

your car shouldnt be that high. liek 13.9-14.1 is what it needs to be, if your voltage regulator is going out, or alternator is going bad it will spike or drop

here is a test

Start your car, disconnect the negative battery terminal. if your car runs your battery sucks, if it doesnt your alternator does.

[boriquaS13]

HEY captianclutchkick you might have a parasitic draw on your battery. Looks like your alternator is charging, I've read in the rb forums about people who have done the swap their ECU stays awake when the keyis off. They suggested installing a relay in line to eliminate the draw. Hope this helps.