At 12:42 PM 7/21/2003, you wrote:
>i read in the archives that Optima does NOT recommend
>anything less than a 15 volt alternator output, if
>this is true, then we are all undercharging our
>optimas becouse the vanagon's Alt charges around
>13-14V.
[snip]

The stock Bosch alternator is actually a pretty good piece.
It's decently made and has good current capacity.
The problem is that the crummy little internal regulator
is lazy and tends towards low voltage. Also it measures
the voltage *at the alternator* instead of at the battery
so when the electrical load is high, the voltage drop
across the charging wire (from alternator to battery)
causes the battery to see very low charging voltage
particularly under high electrical loads.

A reasonably simple (and cheap!) cure is to remove the
stock internal regulator, and replace it with a nice Ford
style external regulator. This works VERY well on the
Bosch alternator. You need to cut a couple leads on
the back side of the internal Bosch regulator and solder
1 wire on that will go out to the external (Ford) regulator.

Also, while you are at it, run a small wire from the regulators
"voltage sense" terminal up to the battery, so the regulator
measures the charging voltage AT THE BATTERY and
compensates for the voltage drop across the charging wire
and keeps the battery charge voltage much more constant
regardless of electrical load.
I did these things to the alternator that was in my vanagon
and loved it.

I don't have the URL's for the sites I found it at, but the
external regulator conversion seems popular with the Volvo
crowd. Type -Bosch Ford alternator- into a search engine and
you should find several websites with instructions on doing
the regulator swap.
It's pretty easy and works GREAT!

Steve
EJ22 -> '86 Westy "Escape Pod"