Where to locate fuse block and switch after adding second battery??

[Jester5000]

Hi,
After reading all the very informative posts, I'm still left with a few questions. I'm new to big boats (2003 17' Legend Xterminator, 90hp 4stroke) and decided I'd like to add an additional battery for house purposes. Currently, the boat has one mediocre starting battery in the stern, with everything going to it (livewell aerators, lights, bilge, stereo, motor). I will be add a fish finder and downrigger as well. There is a crappy looking fuse block under the console, but nothing connected to it.
My thoughts were to buy a group 27 deep cycle/starting battery, a Blue Sea 9002e 1/2/both/off switch, six position Blue Sea fuse block.

Being new, my questions are as follows:
1. Do I mount the fuse block and switch in the battery hold area at the back, or under the console, or a combination??
2. I'm assuming all the wires that currently go from the console can go to one side of switch, including motor, and have the radio, fish finder, downrigger to the other side? Is this the best way?
3. With the radio and fish finder at the console, where should those wires go, to the stern fuse block, or another fuse block/panel under the console?

I only want to do this once, and prefer to do it properly

Any other suggestions or comments are welcome.

Thanks in advance.
J.

 

[glenn property of pam]

1/ the fuse panel should be mounted in a area where it can be accessed while on the water. laying down under the console in 2' chop trying to find a problem sounds fun but beats hanging off the back of a boat trying to get into the engine bay.
On a side note its cheaper to mount the fuse block near the most points of use which is why you may find more than one fuse blocks on a boat.
2/ What switch? if you mean the dual battery switch then all the wires will go to the fuse block and one wire will go from the common of the dual switch to the fuse block. Now to contradict what I just said, If you want a house battery then you should use 2 fuse blocks and run one wire from each battery to its own fuse block then divide the load between engine/moving related (lights, bilge pump etc) and other loads. Considering how the house battery is going to be recharged should help you select which circuits go where
3/ see number #1
There is no real right or wrong way to wire the batteries as it will depend on the alternator / charging system / amount of time you will be running wot / why you need a second battery / etc / etc
Personally I would just wire the boat like it had one battery then either carry a jump pack or add a second battery / dual switch that would only be used if the first one went flat. (either one can be the first battery)

 

[Jester5000]

Thanks for the response!
1/ I didn't consider multiple fuse blocks...wish I thought of that before I bought 20' of 8 gauge wire to run from console to stern.
2/ Sorry, should have clarified, yes, dual battery switch. Currently, all of the wires that come from the console are from a breaker panel on the dash and go directly to stern battery, hency why I thought I can connect them to one terminal of the battery switch directly ("terminal 1"), without going through new fuse block. All other wires (radio, fish finder, downrigger) should then go through the fuse block, and to other switch terminal ("terminal 2"). Does that make sense?

That leaves me with one question. If dual battery switch is then set to "1", console gauges etc will work and battery gets charged while engine is running (tach, speedo, volt meter, fuel gauge), and radio/fish finder/downrigger will not work. Opposite if I turn battery switch to "2". Correct? If so, then your suggestion of wiring like just one battery makes sense...

I guess reading all of the different posts and ideas on how to add batteries, switches, fuses, wiring, etc, I may be overthinking this

 

[bruceb58]

If you have a 1/2/both switch, the batteries get tied to the terminals 1 and 2 and all loads(fuse boxes) get connected to the common terminal. All the loads will be on at the same time to whatever battery you select.

There is another type of switch you can use that allows you to have the loads separated between the batteries and the switch is a double pole singe throw switch with an addition position that connects the two batteries together.

Nothing wrong with having two fuse panels. My Wellcraft has that for unswitched items that are in the engine compartment area.

 

[Jester5000]

Ha!...I realized my mistake in battery switch wiring after looking a bit more carefully at wiring diagrams...:facepalm:
Keeping it simple seems like the way to go.
Thanks for all the advice.