355 house batteries

[Murrdawg]

Hi, new member with 1998 355 twin 7.4L MPI w/Kohler gen.
Only have 2 group 31 DC batteries and small starting battery for generator, don’t think the 31’s are going to be enough for 4 days without dock or generator, where, and how, to locate more batteries in engine room?

[plittle2005]

Your 2 31's are starting batteries (FLA's, good) and need to be isolated from the house loads to ensure starting after a long shutdown. Do NOT use for house loads.

In my '92 350 AC, I have room for 4 FLA 27's between the stringers in the engine room, 2 starting only and 2 house.

For future, I intend to just swap in 2 LifePo's for my 2 FLA house batteries and charge them with a appropriate DC-DC off of one of the engine/FLA batteries .

On shore power, the start batteries will charge from the on-board charger. and charge the LifePo's via the DC-DC charger.

ALWAYS isolate start from house!!! Don't ask how I know! But that guy on the beach with the dinghy who brought his battery out to jump my former boat......ought to be canonized! A saint!

[g36]

If you'll use the search feature of this forum on house batteries you'll see much discussion on type and load and how long to expect to run them. As far as types and size you will need to determine your house needs to have a good house bank setup. Otherwise your just shooting in the dark on what you'll need to purchase and install.
I run trojan 6 volt golf car batteries in my 405 and my previous boats. Last a long time for me, a great house bank battery.

[g36]

If you'll use the search feature of this forum on house batteries you'll see much discussion on type and load and how long to expect to run them. As far as types and size you will need to determine your house needs to have a good house bank setup. Otherwise your just shooting in the dark on what you'll need to purchase and install.
I run trojan 6 volt golf car batteries in my 405 and my previous boats. Last a long time for me, a great house bank battery.

[buster53]

Just curious..why can’t you use your genset?

[Murrdawg]

Just in case I don’t want to use gen set. We anchor in some very quiet spots and the longer we can live off the batteries, the better.
Hoping to use current 31’s for house batteries and maybe add one starting battery. Just no more room between stringers for more batteries, so maybe in front of engines?

[mjk1040]

Maybe a portable solar charging system? When on the hook only use one battery, not both, your only draw is the, water pump, sumps, fridge, lights and radios. Converting lights to led would lower 12 volt consumption too. You could store an emergency battery under the galley table next to the hot water heater with a disconnect. You have options!