No way to turn power to motor off but not house?

S

serpa4

New member
Just thinking aloud.
On my Venture 26, there is only one battery selector knob, on/off/combine.
So, looking at the wiring on Blue Sea systems switch 5511e, when on, both the start battery to motor is connected and at the same time, the house is connected to the house battery.
So, if you are on anchor for a week (which I do plan to do), I cannot shut off power to the engine?
Seems strange.
I don't' see a breaker to disconnect the engine from start battery.
 
What you have sounds typical of what I have seen in the boat and RV industry. But there are ways to easily isolate the starting battery as well. I have my ways and others have their's....they all work. However, I wouldn't worry about this. A healthy starting battery will be fine for many weeks/months connected to a outboard and still start just great.
 
Why do you want to turn of power to the motor, but not the house? When the motor is not running the draw should be very little (basically just the ECU).

My boat has a 1-2-Both switch. The two batteries are the same size and type. Normally batt 1 is the main, and batt 2 is the reserve. Pretty much all the time the battery switch is on 1 when the boat is in use. It gets switched to Both sometimes for a start after anchoring out overnight. Later the switch gets set back to 1. Whichever battery is selected powers the whole boat.

KISS prinicple. I do have to keep tabs on what the battery switch is set to.
 
My understanding from another thread is that you're replacing an ACR with a DC-DC converter that charges a Li house battery. The simple solution for what you want to do is to replace that battery combiner switch with a simple On/Off battery switch. Start battery goes on one side and the unfused starter cable and a fused cable to a positive bus bar go on the other side. The fused wire to the CD-CD converter then goes to this positive bus bar, along with (if you have them) a shore charger for the start battery and a fused wire to a windlass. If your bilge pumps are connected to the start battery, now would be a good time to consider moving them to the house battery, which I think is preferable.

In lieu of buying a new On/Off battery switch (<$50), you could probably rewire the existing switch for the same function, but I would advise against it because now the switch labeling will be confusing, which could potentially be a safety issue in some odd circumstance.
 
You could add a main on/off switch to the outboard. You might also look at how much draw you have on your outboard, it might be so negligible that it's not worth worrying about.
 
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