The batteries did not expel any liquid electrolyte, but did smell like acid when charging. (burned my nose and eyes slightly)
They're wired as two pairs in series, then parallelled at the pos and neg terminals/cables.
I also suspect my meter, which is a digital TrueValue Hdwe $49 job, set on DCV, 0-20 volt range. My "good" VOM disappeared during the move from my house to the boat
Initial, pre-installation terminal voltages of the new individual batteries were in the range of 6.8 - 7.5 V, so the batteries and the meter were presumed to be OK.
There are no isolators or combiners in the setup; there is a Link 10 shunt in the ground cable setup, but the Link isn't connected as yet.
It's a 12V system, not 24 or 32.
Rick, yes, both battery banks seemed to be charging at 18+V. That's what initially prompted me to replace the alternator-regulator and to replace the starter bank alternator
(which was my spare) with the recently rebuilt OEM, 51 amp Motorola alt. After the changeout, the alternator output voltage for starter bank (with the 'new' Alt and regulator) was showing 18+, which was when I discovered and replaced the broken ground wire from the alt ' -' plug
to the engine block.
All cable in the system is over-sized; 1/0 & 2/0and is less than 2 years old.
With the system off at the master breakers for the last 30 hours or so, terminal voltage at the house bank is 11.3V.
One other fact inadvertently omitted from my original post:
After I installed the replacement alternator and regulator, I accidentally attached the wire from the AC tap on the alt to the wrong connection on the electric
tach. That caused the wire (and the engine harness green/grd wire) to BURN UP!
However, the two battery banks and charging systems are completely separate, with only an actuator circuit at the ignition switch (which was unaffected) in common. I can parallel the two banks by means of a permanently installed, switched cable between the two battery master switches.
The "overcharge" condition existed before I made that wiring