possible to rearrange batteries from"port" and "STBD" to "House" and Starter"

Simplest solution is to fix your emergency crossover switch and use your generator more. Then add more battery capacity to the house bank if you need it. No rewiring needed.

 

Before you consider rewiring....

How old are your batteries, what kind are they, and what shape are they in?

A fridge typically draws about 8-10A while it's running and depending on where you are and how hot it is (and whether or not the cabin is air conditioned), and how often it's opened, it would typically run about 50% of the time. So figure on average it draws 4-5 amps continuously, but could be a bit more or less. For a SINGLE group 31 battery, that should easily last 10 hrs before you'd have a struggle starting an engine with the same battery. If you have two 31's in parallel, that'd be over a full 24 hour day.

 

In addition to the battery age, check your wiring and check the condition of your fridge. Re-arranging the batteries is possible but it looks like a pain, at least in my boat.

also, a single starter pack will be charged from two alternators, the internet has conflicting info on whether that’s good or bad.

 

Your battery set up is pretty much the standard for diesel SRs and maybe some gassers. Two batteries/engine and one for the gen. On my 420DA, the starboard 2-act as cranking batteries and also supply all power to the helm. The port 2-act as cranking batteries and supply power to the “house.” Stand alone battery for the gen. Thrusters generally have their own battery(s). Previous 44DB was same less the gen battery. Only 4-total. Never had an issue, but the gen is always running before unhooking shore power and is shutdown once shore power is reinstated.

Bennett

 

I suspect you will be looking to rather expensive modifications to ensure the alternators are properly configured and the switching won't lead to unexpected issues.
On my 400DA I simply added one extra battery to the house/starting bank when I replaced all of the batteries. There was enough room. I also had an inverter and really needed the additional amp hours.
Re the solar panel(s) - you'll never be able to install enough to supplement a refrigerator's current demand on that boat. For example, a 320-watt panel (about 36" X 60") only really delivers about 60% of the rated output and even less if laid flat and that is on peak sun time. You simply will never get the results desired.

 

I've got the same fridge and battery setup that you likely have, @Wild Rover . You should be able to easily do an overnight without killing your batteries with just one fridge and other random accessories drawing from your batteries.

Being judicious I've been able to manage two nights with two fridges on a prior boat (Sea Ray 340) without the generator and still being able to start the engines.

Battery testers are cheap and handy to have around:
https://www.amazon.com/gp/product/B000AMBOI0/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

New batteries aren't so bad either if you don't go full AGM. I've had great luck with Duracell brand batteries from Batteries Plus. Good for 3-4 seasons. 10% off if you order online.

 

That is a whole bunch of work just so you don't have to run your generator as much. The generator is there so you can live at anchor - use it for that purpose.

 

Over the years the sea ray designers have proven to be pretty good with the decisions they made on boat design.

sounds like fixing the crossover switch would be cheaper than retiring batteries. Also, are your batteries current? They don’t last forever

 

I have all group 27 flooded now but this spring will switch stb side that slso powers the fridge to group 31s. Four 6 volt golf cart batteries would have more amps than two 12v 31s but I dont think there is enough space and would require new cables.
I personally prefer flooded as less cost, less wt?, less install issues, last almost as long and are 100 percent recycleble.
Changing to the more common house and starting banks makes sense but not sure its worth the effort. There is a benefit to the system sr used but I cant remember it at the moment.

 

I think you have 2 threads going on the same issue. I did some rough math on solar panels in this thread. These guys will check my math I'm sure! --> http://clubsearay.com/index.php?thr...997-400-diesel-sundancer.111777/#post-1377331

Bottom line, probably the easiest option as mentioned is new batteries, add a 3rd to the starboard side, and yep, run the genny for a few hours here and there.

I have the stock battery set up, but added (2) 300Ah LiFePO4 batteries to run an inverter and act as an additional "house bank" Of course the biggest issue is getting and keeping these batteries charged. Sea Rays are power hungry!!

I'm a fan of the Duracell AGM's. They cost a little more, but they require 0 maintainence and last longer than the Flooded. Getting to these things and lifting them out is a total PITA and the fewer times I have to do it, the better!!!

 

One thing I always do, start the generator then unplug from the dock, back to a dock, plug in and shut down the generator. Could be days in between that sequence. Your generator will love you for it.

As to the batteries and wanting to shut things down and run off of the batteries, measure the room you have and look into an 8D for the starboard bank. I only have two batteries on the boat. 8D's port and starboard, the generator runs off of the port battery and the house off of the starboard. I get 6-7 years out of the 8D's almost twice as long as the 31's and there not as expensive as two 31's. If there isn't enough room for an 8D, look at a 4D, that is still more reserve capacity then two 31's are.

Also get your parallel switch fixed. Good luck!

 

Which 8D's do you recommend? Link?

 

All 8d's are the same size, but I have had really good luck with NAPA batteries.

Marine rated: https://www.napaonline.com/en/p/BAT8276?impressionRank=1

The one I use: https://www.napaonline.com/en/p/BAT7271?impressionRank=3

I like the caps for the cells better, makes putting water in easier. I am only changing these out after 7 yrs this winter.

 

I am in the process of repowering my DC system on my 380 diesel boat. First I am upgrading my ProMariner charger from 30 amps to a new 50 amp unit. (more amperage less jenny time). Secondly I am replacing batteries with AGM's as follows, 2 Victron GP31 Super Cycle 12v 170AH 770CCA in parallel. This will yield 1540 cranking amps and 340AH. For the heavier draw side, I will go with either four VMAX Tank XTR31 6V 235AH 770 CCA in series parallel yielding 1540 cranking amps and 470AH, or three VMAX Tank XTR12 12V 155AH 790CCA in parallel yielding 2370 cranking amps and 465AH.

The choice between the 6v and 12v will be determined once I measure the space and gauge the weight difference. Either way I will have a decent bank storage for staying on the hook.

The last addition to all this is a 2000W ProMariner True Sine Inverter expected to power TV, Microwave, Coffee maker and toaster, (now and again) without running the generator. All of this is after a lot of research and talking to some knowledgeable folks.

 

I did this, and it was really easy. It was changing over a couple of wires on the switch side and couple on the relay side... other than that it was perfect. Works like a charm