PNW
Veteran Member
- Joined
- Mar 22, 2024
- Messages
- 35
- Location
- Seattle, WA
- Vessel Name
- M/V Changing Tides
- Vessel Make
- 1985 CHB 38' Trawler
Preface: I made a couple of posts about the mess of wiring issues I found on this new boat, but I only had the energy to post in the intro thread I had made so it was hard to get precise feedback, thus it was rec'd to me to make narrower questions in the specific forum for that category. This is my first chance to do a proper post like that, as I have been spending all of my available time doing actual work on the boat when I had only energy for either working or writing about the issues I found.
What I've done so far: I was able to figure out most of the system interfaces just by doing logical breakdown physically of the lines going here and there, but the one thing that has me stumped is the power distribution panel (circuit breaker panel? DC panel?). I have spent a fair amount of time just removing the super old wires that were just dangling there from yesteryear, and removing the old cable management system which was obscuring everything useful from my view and hiding a lot of really messed up bits and bobs like bundles of ends shoved into wire nuts or entire lengths of cable with only duct tape for insulation/shielding. I had to remove the primary battery selector switch and battery cables and batteries, so now I am left with mostly current (no pun intended!) wiring that contains still-useful endpoints (i.e. temp guage, indicator light, engine room air blower, water pumps, bilge pumps, horn, etc) BUT no batteries or big thick cables or 1-2-both-off selector.
and I have the ~1 AWG wires coming into the helm area from the bow to send power to the windlass (and it is properly controlled and fused at the bow already so just assume two cables at the helm are the endpoint here) and these used to be hooked up to the battery selector switch, thus bringing power from the old start battery bank, which had been used as the 12v side of the power system, to the windlass allowing the old batteries to be used for starting, all the 12v components, and powering the windlass, but remember I no longer have those batts, cables, or switch hooked up because it was melted from corrosion resistance heat.
Project reqs: I want to use the 12v components on the boat that still work fine.
I am not using shore power.
I am also not using the genset or the inverter/charger.
I want the engine start batts isolated so that each engine alternator charges it's own start battery, 1 battery right next to each engine, this is already set up and working. These are well-maintained engines so no I don't care about a "cranking for a long time" backup plan at this time.
I just need to be able to install a 12v battery directly at the helm where the distribution panel is, and have that battery power everything that has a DC breaker and is wired correctly.
The problem: I don't understand what I'm looking at when I need to hook the panel up to the battery. I see the shunt and I believe that thicker cable coming off of it goes to the POS(+) side of the battery, but I just am not putting together the mental pieces necessary to understand the other side of the diagram the NEG(-) side. So far no matter which black ground looking cable I try hooking up to the (-) terminal, I can't get any of the breakers to work, and am not measuring voltage at any of the points where I know what is supposed to happen there. I know that I am missing some understanding of where else to look for voltage to track down this (-) end cable and finish hooking up this panel, but instead of sitting there with my multimeter trying to figure it out through process of elimination, I would like for someone to just explain to me what is going on with the wires, jumpers, bus bars, terminal strips, and whatever else exists at the backside of the panel! I have watched a bunch of videos and looked at tons of forum posts and examples of bad and good wiring but I still don't understand what is the most basic version of this that has multiple circuit breakers but is not just a huge bundle of untraceable wires in a loom. My only other option is to just keep disconnecting things until I have something so basic that it's the same as if I just started from scratch and put a new panel together.
What I want: A written explanation of the basic I/O of DC breakers in a panel, without the inclusion of the AC side or shore power or any other extraneous parts. Or a diagram of this MVP of a battery hooked directly up to a panel without a selector switch or involving the engines or house bank at all. Or a picture annotated showing what the foundational parts are in said MVP design.
I will include two photos but for the rear of the panel it's nearly impossible to photograph right now with how tight all the wires are...also the panel doesn't have a hinge or anything so it's kind of tough to tell how to get better access. I will try today to remove the screws from the panel edges to see if it is possible to take better photos and have space to move wires and see where they all go. But I would love to get things at least energized today so I can move on to the system stuff that requires 12v.
Thanks in advance anyone who read through it all, I really want to understand this instead of just making it work and moving on!
What I've done so far: I was able to figure out most of the system interfaces just by doing logical breakdown physically of the lines going here and there, but the one thing that has me stumped is the power distribution panel (circuit breaker panel? DC panel?). I have spent a fair amount of time just removing the super old wires that were just dangling there from yesteryear, and removing the old cable management system which was obscuring everything useful from my view and hiding a lot of really messed up bits and bobs like bundles of ends shoved into wire nuts or entire lengths of cable with only duct tape for insulation/shielding. I had to remove the primary battery selector switch and battery cables and batteries, so now I am left with mostly current (no pun intended!) wiring that contains still-useful endpoints (i.e. temp guage, indicator light, engine room air blower, water pumps, bilge pumps, horn, etc) BUT no batteries or big thick cables or 1-2-both-off selector.
and I have the ~1 AWG wires coming into the helm area from the bow to send power to the windlass (and it is properly controlled and fused at the bow already so just assume two cables at the helm are the endpoint here) and these used to be hooked up to the battery selector switch, thus bringing power from the old start battery bank, which had been used as the 12v side of the power system, to the windlass allowing the old batteries to be used for starting, all the 12v components, and powering the windlass, but remember I no longer have those batts, cables, or switch hooked up because it was melted from corrosion resistance heat.
Project reqs: I want to use the 12v components on the boat that still work fine.
I am not using shore power.
I am also not using the genset or the inverter/charger.
I want the engine start batts isolated so that each engine alternator charges it's own start battery, 1 battery right next to each engine, this is already set up and working. These are well-maintained engines so no I don't care about a "cranking for a long time" backup plan at this time.
I just need to be able to install a 12v battery directly at the helm where the distribution panel is, and have that battery power everything that has a DC breaker and is wired correctly.
The problem: I don't understand what I'm looking at when I need to hook the panel up to the battery. I see the shunt and I believe that thicker cable coming off of it goes to the POS(+) side of the battery, but I just am not putting together the mental pieces necessary to understand the other side of the diagram the NEG(-) side. So far no matter which black ground looking cable I try hooking up to the (-) terminal, I can't get any of the breakers to work, and am not measuring voltage at any of the points where I know what is supposed to happen there. I know that I am missing some understanding of where else to look for voltage to track down this (-) end cable and finish hooking up this panel, but instead of sitting there with my multimeter trying to figure it out through process of elimination, I would like for someone to just explain to me what is going on with the wires, jumpers, bus bars, terminal strips, and whatever else exists at the backside of the panel! I have watched a bunch of videos and looked at tons of forum posts and examples of bad and good wiring but I still don't understand what is the most basic version of this that has multiple circuit breakers but is not just a huge bundle of untraceable wires in a loom. My only other option is to just keep disconnecting things until I have something so basic that it's the same as if I just started from scratch and put a new panel together.
What I want: A written explanation of the basic I/O of DC breakers in a panel, without the inclusion of the AC side or shore power or any other extraneous parts. Or a diagram of this MVP of a battery hooked directly up to a panel without a selector switch or involving the engines or house bank at all. Or a picture annotated showing what the foundational parts are in said MVP design.
I will include two photos but for the rear of the panel it's nearly impossible to photograph right now with how tight all the wires are...also the panel doesn't have a hinge or anything so it's kind of tough to tell how to get better access. I will try today to remove the screws from the panel edges to see if it is possible to take better photos and have space to move wires and see where they all go. But I would love to get things at least energized today so I can move on to the system stuff that requires 12v.
Thanks in advance anyone who read through it all, I really want to understand this instead of just making it work and moving on!