Dual Battery Question

PA228G

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I searched for a similar question but may have missed this. I also know from reading other posts that wiring is a "hot" topic (no pun intended) that can lead to spirited debate, but here goes.

Project started as a simple pre-launch install of a couple of LED lights and new VHF, but the undocumented rat's nest - multiple open ended leads attached to unmarked fuses, etc. - at my accessory panel drove me to basically start over. Bought a nice new fuse panel, a couple of terminal buses, labeled what was obvious and began adding back the unmarked circuits to figure out what's what. All is proceeding okay, except ...

1. I have a simple 1/2/BOTH switch in the transom and two POS leads that appear at the helm. I was half expecting that if I had the switch to "OFF" the meter would read zero volts on the panel leads to avoid total drainage of the system if something was left on - nope. I also thought with 2 POS leads one would be dead depending on the 1 or 2 switch position - Nope. So my question is - Is the only function of the 1/2/Both switches to insure you can get as much juice to start the motors as possible if the start battery is low? Or is the 1/2/Both switch not installed properly, i.e., should I be able to run items on the accessory panel ONLY from the house battery?

I'm half thinking of re-doing the aft end too - the transom well is almost just as big a wiring mess.
 

BobP

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When you turn the selector to OFF, the only remaining ship's load still to be fed is automatic bilge pump circuits (always-on with individual waterproof fuses probably at stern). If it's the battery selector switch to OFF or another heavy duty switch ON/OFF type, as long as it's in the stern and turns off the ships power - fine.

You may also have an always on feed running up to the bridge for radio memory circuits, galvanic isolator indicators/alarms, Flowscan memory, etc, as I have added.

My older Grady has an express feeder additionally directly to hardtop as a second supply fused at battery, for emergency use of VHF radio should remaining ships power system go down, or 2nd GPS, whatever.

Check your owners manual for the factory chosen method - wiring diagrams, I undertand these are available on the Grady web site.

There are a zillion DC system configurations one can come up with, to suit one's individual fishing and boating needs. You can many of them at the Blue Seas website.

As long as you know how to operate the system properly, it is of quality materials and construction so to be dependable and not burn down the boat, that' all that matters. No expert will ever state this, since an expert always has to have an opinion, their's being the only right way of course, and whatever you have is no good !

Glad those dark clouds cleared out of here and the air has been easier to breath last few weeks. What a joy!
 

jehines3

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Grady is pretty good about adding a breaker in the battery compartment for the house panels. Does your boat have such a breaker. It may have been moved improperly which bypasses the battery switch.

I, like Bob, have a 24 hour circuit in my hardtop for the VHF. Depending on the level you want to get to depends on how much time and money you want to put into the project.

"""So my question is - Is the only function of the 1/2/Both switches to insure you can get as much juice to start the motors as possible if the start battery is low? Or is the 1/2/Both switch not installed properly, i.e., should I be able to run items on the accessory panel ONLY from the house battery? """

Depends on what your preference is. I never run my house off my motor batteries. I buy starting only batteries for these and do not deep cycle them. My house on the other hand is a big honking 4D which works great as a house bank. I think a properly designed battery system should be simple enough for a cave man and leave no room for errors in operation. jh