The two battery boxes on Pilot 34s are designed to take a 4D and maybe an 8D. Two 6V GC batteries will fit in that space with some left over, but definitely not enough for two more. A single Group 31 will also fit which is plenty to start either the twins or the single (mine).
The twin Yanmar 4LH 220 hp engines in the Pilot 34 come with an internally regulated Hitachi alternator. Like most of their type they don't put out anywhere near their rated current normally as they are designed to replace the small amphours used to start the engine and keep up with external running loads, not to replace lots of amphours.
The NextGen 3.5 genset cannot be retrofitted with an alternator.
I really like David’s suggestions. There are a lot of ways of doing it so sitting down and playing with with ideas on paper is time well spent.
...I think 4x GCs will fit in the space of 1 8D... but it's been a while since I was checking all that, so might be mis-remembering.
-Chris
I too.
My KK was also set up like the OP, with two house banks, one used for starting.
Stupid to me. That was the first change we made before leaving the dock.
Combined the two banks into one and bought one G31 to start engine.
Use one switch for HOUSE BANK & One switch for START BANK
Put all master panel loads on HOUSE (panel under rear cockpit hatch)
Use one START BANK for both engines and the genset
Feed all charge sources to HOUSE BANK other than start banks engine alternator
One alt still feeds direct to HOUSE BANK (bigger of the two, if one is)
One alt feeds START BANK
Install a Blue Sea ML-ACR 7622 between banks on the load side of the switches. This allows for emergency manual cross-connect (use house for everything with start off/isolated, or start for everything with house bank off/isolated). This will also allow both alternators to charge both banks, automatically, thus doubling your bulk charge capability into the house bank.
Keep it simple there is no need for more than two banks on a 34' Mainship.
Without a diagram of how it is actually wired at this point in time it's impossible to say how you do this in the most efficient manner..
Which bank(s) are best for the windlass and bow thruster? Right now mine are off the house/port start battery. Seems to me since both items are most likely to be used when the engines are running they should be hooked into the start bank.
Which bank(s) are best for the windlass and bow thruster? Right now mine are off the house/port start battery. Seems to me since both items are most likely to be used when the engines are running they should be hooked into the start bank.
Yes, two group 31s will fit on one side but not in the 4D/8D boxes. You will have to use new boxes and turn the batteries 90 degrees. But why?
And two GC batteries will fit in the existing box.
One 8D box can fit 3 GC batteries. My house bank of 6 GCs fit into 2 8D boxes.