Dennis, I have measured a few 86+ Vanagons and I haven't found very much
of a drop between the battery and the alternator compared to the rest of
the wiring. I just did about 20 different voltage measurements on an 87
Syncro and the drop from the alternator to the battery was less than 15%
of the staggering 2.1 volt drop at the passenger low beam headlight
wiring at worst case. I measured at several points in between with first
the low beams on, then also the front heater fan on speed 3, then also
the rear window defogger on. The voltage at the battery dropped some
each time and the voltage at the fuse panel dropped more.

With just the headlights on I had a .19 drop from alt to bat, another
.28 from bat to fuse panel, another .86 drop from panel to headlight,
another .4 drop from headlight ground wire to chassis ground near
headlight.

That is a total of 1.33 volts lost on the voltage leg plus .4 on the
ground leg for a total drop of 1.73 volts at the light with just the
lights on.

Running a #8 wire from the battery to some new relays and also adding
new grounds for the headlights looks like it could boost the headlight
voltage by 1.5 volts and even more with the above mention electrical
consumers turned on. I did this on my old 87 and the headlights were
markedly brighter after.

Mark

Dennis Haynes wrote:
>
> Actually, you really want to improve the current path from the
> alternator to the fuse box, or headlight relays. The alternator is the
> current source when the engine is running, not the battery. An
> additional 8 gauge wire from the alternator will give at least a 1 volt
> improvement when the lights and heater fans are running.
>
> BTDT
> Dennis
>
>