check voltage at alternator and compare readings. You may have bad
connections or bad wire from alt to battery. Usual drill, clean
connections etc, try again, compare readings to get voltage drop.

alistair

On 3-Feb-11, at 10:43 AM, Don Hanson wrote:

>  My bosch alternator,  a rebuild  just a few years old, is giving me
> 13.10
> +/- volts at the passenger side (starter) battery terminals.   I am
> thinking
> "new Voltage regulator"...right?  When I add rpms or load (turn on
> headlights)  nothing much changes with the voltage.  anyone care to
> comment
> or confirm that another regulator is the 'right stuff?"
>
>  Don Hanson