House battery type and also main circuit protection fuse

[Solent Bombard]

Hi

I'm just about there in the boat refurb to start putting in the electrics but i want to run a second battery for my house electronics.

Which are

Icom m323 vhf
Garmin 451s
Hella naviled lights
Bluesea 12v socket
Bluesea dual usb socket

I'm trying to determine if this fuse would be good to use between the battery and the fuse box as bluesea say on there circuit diagram that I need main circuit protection of no more than 125a (which I guess I'm way under).

ANL Fuse Block with Insulating Cover - 35 to 300A - Blue Sea Systems

I aim to use this between the battery and the 12 gang fuse box.

Also what's the best battery to have as a house Battery as currently I have a numax mv26mf for engine starting but I guess I need a different type for the domestic power.

Thanks

[Nightfisher]

From your list of items, I'd say the total fuse size to handle all on the main power line (AT THE BATTERY + Seven inches),depends on what you plan to run off the 12 volt socket power-amp wise? Add all the max amp draws for each item , plus anything electrical you may add later then look-up the gauge of the main power wire required from battery and add 2 gauge sizes to know the proper main wire gauge then add the total the main fuse size of what U have added-up, plus 5 Amps.

Two reasons, 1) The heavier the gauge Main wire you use the more power that will be lost during the DC Voltage trip from the battery to the main fuse panel. 2) The main fuse at the battery is there only in-case a short occurs along the route from the battery to the fuse panel. All other shorts between the fuse panel and each powered-item should they occur, will blow the small fuse in the panel.