question

Common practice on boats is to fit a dc isolator for safety. Also a link for emergencies, back up for engine starting etc.

Curious why your fitting a DC to DC changer when your not using lithium? It would be better to charge via an argo fet diode direct from the main engine or engines, better still using a smart regulator to increase charging efficiency.

Consider lithium batteries, the efficiency gains are worth the expense and they are cheaper in the long run especially for use with inverters.

Also, consider using a lynx shunt and power in as a neat solution rather than the 712 batt monitor

Hi @Dirtdiver1977

Design is your most important challenge. Make a mistake and the kit you've bought may be wasted money. So it's good you've asked.

Head for the Victron website, where there's masses of info. Even example schematics related to the kit you're considering. And in those schematics you might see other kit included and wonder why it's there. There'll be a reason, so then ask if you don't know. This link is general design stuff.. https://www.victronenergy.com/markets/marine

One thing I suggest you reconsider is using a 12V base. I started there and ended up at 48V, much better. Sure I use 12V too, an Orion fixes that.

The beauty of Victron kit is that there's almost always alternatives in the product rrange. This is for practical and personal preferences. Eg. you might choose a Multiplus with a cheaper onboard GX rather than a Cerbo/Touch combo if you prefer laptop/phone/glassbridge access. (also depends on what bells'n'whistles you can do without).

One thing in your list you could probably scratch is the Battery Protect. Useful with serious dc loads, but the Multi can do that for ac, and VRM can be set to alarm on many things.

So keep an open mind. And don't get too absorbed at this stage with choosing isolators/fusing etc. Try to define what you want to do, and how you want to control it.

So this is the plan for our Trawler. There is the fridge missing on the A/C side..lol. But the outlets will be port/starboard sides with 1 gfci on each, small on demand water heater and an a/c unit. the majority of my loads would be dc and have thought about a 12v fridge as well but we'll end up with 80 Qt Bodega fridge/freezer (12v & 120V) combo as well below the galley floor. Only time I really see using the 110v side is on shore power mostly other than the fridge being under way. Have even thought about adding in a a/c selector switch for shore power or a small generator to help with the battery charging if needed when we're on a mooring ball.