T&T: Inverter Problems

[Robin]

"...The technician said the alternator supplier
said a larger alternator would not work because of the different batteries (12
and 6 volt ) Technician said it would charge the weakest battery and then
quit...."

Not so....The "problem" as stated above is incorrect.....the technican, if
that's what he said, is wrong. It's true the weakest battery will draw the
most charge initially, but all batts will charge appropriately. And keeping
all banks tied together during discharge can lead to a pooped out start
battery.

Charging as described in a separate post, keeping the banks separate, is one
solution. Another is to use an automatic battery combiner, such as PATHFINDER
that connects battery banks together when charging (say above 13 volts) and
automatically disconnects when charging ceases (perhaps 12.2 volts). West
Marine also carries combiners.

Also, if the engines are run long enough cruising then even a modest
alternator will eventually get the charge up. If speed is required, an
alternator that puts out about 25% of the bank amp hour rating is required for
wet cell batts...Say the bank batteries total to 800 amp hours....then the max
charge they'll accept is (during bulk charge) about 200 amps...that's the
ideal size alternator.

Rob Brueckner
Hatteras YF