See the article at http://www.yandina.com/combInfo.htm#Q33 on
alternators in parallel.

I don't like seeing a switch between the battery and the alternator -
if you turn it off while the engine is running you run a serious risk
of damage to the alternator. A zapstop will add some level of
protection and put a warning right on the switch so those unfamiliar
with the danger are informed.

Regards,

Andina Marie Foster,




Jason wrote:
I'm building a new battery system for my Albin 27 trawler. The boat
previously had a 1-2-Both-off switch and two banks of batteries. My new
engine has two alternators and I'd like to take full advantage of this
set-up. My plan is to install a dedicated starting battery with an
on-off switch, a dedicated house bank with an on-off switch and then
have a third switch to parallel the banks in an emergency. This system
is explained in detail in Calder's book and seems to be a good match
for my boat.

My question is this; Assuming I connect one alternator to each bank,
what happens when I parallel the batteries? Will the two alternators
feeding into the system cause any problems? 99% of the time the two
systems would be totally independent.

Thanks,
Jason

Albin 27 FC- "Tonic"
http://www.people.cornell.edu/pages/jek15/