Help needed separating house and start circuits-gctid812014

[njosephson]

What a mess, my boat had two batteries wired to a 1/2/Both switch and no less than 15 pairs of wires hooked directly to one battery or the other (several were lamp cord of course). So I got a box for two golf cart batteries and a blue-sea On/Off/Combine switch and finally got all the necessary battery cables in place but now I've hit a snag. I can't figure out how to separate out the "house" side...

I've cleaned up all the lamp cord and accounted for all the wires at the battery except for one - its a heavier than the rest gauge orange with a purple stripe wire that was hooked directly to one of the batteries and disappears into a harness thats going forward toward the cabin. The fuse panel in the cabin is fed with a red with a purple stripe wire - an identical wire comes from the forward harness and disappears into a wire harness that goes into the engine. It seems like somehow I've got to change how these wires work but I'm leery of pulling wires out of the engine harnesses...

Thanks in advance - the weather is getting so nice I've got to get this wrapped up soon!

[CptCrunchie]

I separate mine by whether they are used with the engine or without. The helm wiring is all starter battery, as are the gauges, trim tabs, trim, Nav lights, etc. My windlass and headlight is also on the start battery, because the only times I use them is when the engine is running.

All electronics including radar, sonar, radios and the like are on the house battery. The cabin lights, aerator and fish wells are also on the house. The anchor light is the only helm switched item run off my house battery.

I have three bilge pumps, two hardwired on the house, and one hardwired to the starter battery (all on fuses).

It'll take a bit to make the change, but once you do, it's a secure feeling to know you have isolated the start battery.

Now, I also wired the batteries very differently; I now use two MBSSs, one on each battery. Then I added a 200A solenoid as a cross-over, switched at the helm, so I can charge the house whenever I am underway. I have an ACR in the mix, but it rarely ever connects the two. Between the solenoid and the two main switches, I never have to leave the helm to charge the batteries, ....nor isolate them.

[sketch96]

I think the heavier gauge orange wire with the blue/purple stripe is the charge wire from the alternator.

[builderdude]

Your 2858 would have been factory wired to run most all loads from the battery bank you've selected at the MBSS. Here is a pic of a Keep It Simple wiring schematic. It's been posted numerous times on this forum and is how I've personally done mine. It'll give you the ability to add future electronics without having to run them through the factory wiring harness.



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[2850Bounty]

"builderdude" post=812037 wrote:
Your 2858 would have been factory wired to run most all loads from the battery bank you've selected at the MBSS.

Here is a pic of a Keep It Simple wiring schematic.

It's been posted numerous times on this forum and is how I've personally done mine. It'll give you the ability to add future electronics without having to run them through the factory wiring harness.

[color]blue wrote:
Ditto Dave!

KIS..... keep it simple!

In my opinion, and re; this size boat......., there is no need to separate out house loads from starting loads other than via what the MBSS already provides.

If wired and cabled as below, either battery bank selection can/will power all 12 vdc on board.

It just becomes a simple matter of good and proper battery selection and battery management! [/color]

[attachment]37273 wrote:
MBSS and Acc panel Pos Neg 2.jpg[/attachment]


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[njosephson]

So I guess in this scenario you manually switch to your "house" battery bank whenever you are at anchor so that the refrigerator/stereo etc doesn't leave you without the ability to start your engine?

[CptCrunchie]

"njosephson" post=812104 wrote:
So I guess in this scenario you manually switch to your "house" battery bank whenever you are at anchor so that the refrigerator/stereo etc doesn't leave you without the ability to start your engine?

By their drawing, that is correct. If you only pilot to a spot, drop anchor and sit for a day or so, this system works great.

I, however, am starting and stopping regularly while fishing. There WERE times when CRAFT disease took over and I'd forget to switch the MBSS. So, rather than touch the big switch, I flip a toggle switch at the helm. That's why I separated my systems and use a solenoid to cross them over for charging. Whenever I fire up the engine, I switch it on, then switch it off when I shut it down. I also have the voltage alarm on my GPS set to 11V, so I know immediately that I need to charge my house battery. To this brain, that IS KIS.

[Happy_Friday]

+1 Sketch96

[Ruffryder]

Alternator charge wire shouldn't terminate at the battery...

[builderdude]

"njosephson" post=812104 wrote:
So I guess in this scenario you manually switch to your "house" battery bank whenever you are at anchor so that the refrigerator/stereo etc doesn't leave you without the ability to start your engine?

Pretty much. I start, warm the engine, and leave the harbor on #1 (start bank) Before I throttle up to get on plane I switch over to #2 (house) Run on, anchor, use house power etc. (for however long) on #2. If she won't start on #2 after an extended stay on the hook, I switch over to #1 and fire it up.

NEVER run the MBSS through the off position while the engine is running, the alternator doesn't like that.

[builderdude]

"Ruffryder" post=812247 wrote:
Alternator charge wire shouldn't terminate at the battery...

Agree, sounds like some things have been "rewired" on this boat.