Generator charging question

[hippieforever3]

I've looked at the charging system diagrams and if I interpret them
correctly the way the generator battery gets charged is either from the
alternator or the generator produces AC which than goes to the
converter and this indirectly charges the generator battery.

I never seem to be able to get a full charge on the generator battery
either off the alternator or the converter. Unless I'm missing
something the generator will always get charged to one diode drop less
than the main battery bank. I think I see evidence of this when I hit
the Aux. Battery switch and the dash voltage meter drops about one half
volt.

Does the charging voltage come into the generator compartment through
the "mystery control box"? or go direct to the battery. What is in that
box? Awful big for just a fuse holder and start switch.

I know I can trace it all out but if someone happens to know, I can
save getting a bad back stooping over for a few hours.

Regards,
GPSGary
1984FC35