I have a catamaran
with a single
house bank and a start battery
for each engine
(port and stbd). Each alternator
goes to a separate battery
isolator that isolates the house and start batteries. The alternators on the Volvo
engines are 60 amp Valeos that have a separate voltage regulator
mounted on the outside of the case. The schematics from the boat builder
have the regulator
voltage sense wire from each alternator
tied together and brought back to the house batteries so that the alternators will regulate to maintain 14.2v at the house battery bank terminals.
The port alternator does this just fine, but the PO had never gotten the stbd alternator to charge the house bank, (the stbd start battery charges OK). I looked into this and found the external voltage sense wires on the stbd regulator are disconnected, so the alternator is being controlled to output 14.2v at the alternator terminals. Subtract 0.6v drop through the splitter and 0.5v drop between the splitter and the house bank and the best case would be 13.1v at the house battery terminals. This isn't going to do much charging!
I'm planning on reconnecting the sense wires so they are tied together per the schematic to see if that resolves the issue, but as I've thought about this more, it seems unlikely that I will be able to get both alternators perfectly in sync due to voltage differences between the two engines.
So what will happen in this case? I'm assuming one alternator will dominate, and do the bulk of the charging
, with the other kicking in when the battery bank voltage is quite low. I don't really see this as a big issue, but am I missing something?
Since my primary charging
sources are my solar panels
and genset, I don't want to go to the added expense and complexity of adding balmar
regulators and centerfielder if I can avoid it.