I having a problem with low voltage at idle. With all accesories on, in gear, foot on brake I get 10.5-11 volts. With no accesories on in gear is about 13 volts. In park with accesories off I get 14+ volts. I have a holley electric fuel pump(7amps), heater, stereo(no subs/amp). Idle in park is 1000rpm, in gear 700rpm. Headlights and rear def seem to take the most power. Im running a rebuilt 65amp GM alternator. The alternator is fairly fresh but i guess it maybe done already. Do I need a bigger alternator for these accesories? Or would this problem likely be caused by wiring(maybe too small from batt to alt; running 10 gauge)?
hmm.. how is the voltage with load when you get the revs up to operating speed (1500-2000 rpm). also what is 14+ is it 14.2 or like 14.8? if its in the higher 14's your voltage regulator sounds shot. and thus being internal may need replacement of altenator, although i've heard you can buy just the voltage regulator for altenators. and crack it open and replace it. the voltage regulator in my honda has similar voltages. my battery lasts 2 years though my stereo equipment loves the supply of almost 15 volts though.. to replace the voltage regulator on in the altenator on the honda. step one. remove drivers side transaxle.
voltage the upper limit is 14.2 volts . why so high an idle ? big cam ? one thing to check are the grounds - battery to block, motor to chassis/body . to much voltage & u could have a problem with the battery overheating & cracking the case .
the newer batterys on the market (since the mid 80's) are designed to take the extra voltage. 14.8 is right where you want it at idle in park with no accessorys on.14-14.2 in drive at idle with heater & low beams is the norm. sounds like you are right there!!! with ALL accessorys on at idle in gear you will be drawing a lot of amperage so your voltage will drop until rpms come up.
