something ive noticed with my car since ive had it, when driving, if i have the rear defrost on, blower on high, headlights on, when i hit the brakes it'll drop to 12 volts and start falling even if its revved up.
im guessing my alternator is weak? belt doesnt slip and the alt has been hosed with oil who knows how many times. i have good ground wires and even added an extra. do they all do it or just mine? the cooling fans make it drop off bigtime. shut evrything off it;ll works its way back to 14 volts. battery is new. did the same on the old battery before it started to go.