voltage across battery when charging ?

[mikew88gt]

Are you sure you don't have underdrive pulleys? Your alternator wants to put out 14+ volts like it should but when you're hooking up your battery it's dragging it down to 12. That's what my car does normally with underdrives. Even with a fully charged battery a car with underdrive pulleys will find itself trying to play catch-up with an electric fan, ignition, fuel pump, etc. If you want to check the integrity of your system try this. By placing a voltmeter along the entire length of your positive cable (from the battery terminal to the start solenoid) while the car is running you will read the voltage drop of that part of the circuit. It should be a lot less than 1 volt with the 2 gauge wire. If that checks ok try the same with your ground cable by going from your battery negative terminal to a ground point up front (usually on the left inner fender forward of the strut) and from the negative terminal to the engine block. These couple of checks will tell if your losing voltage from the wiring.