I have a not-so-classic plastic boat ('82 C&C 37) which I'm slowly working on. Given that it's winter I'm focusing on projects that allow the use of that great tool, the heater, i.e., wiring and re-wiring.
Here's my question for others: the bilge pump is not tied into the 12VDC distribution panel but rather, wired directly off the starting battery. I'm pretty sure that this may have come directly from the factory like this. I'm also pretty sure it is not a very good idea...
I'm putting in all-new AC and DC distribution panels and would like to do as Tim has done on the Kaholee Project which is to have a distribution block that is hot even when the battery switch is off so that the bilge pump is always on.
I'm drawing a blank on this one. Long run (house bank located a pretty far piece from the navigation station) of battery cable to the distribution block? Fuse(s) and location thereof? Bilge pump switch/circuit-breaker on the panel to be able to shut off the power?
If anyone has a wiring diagram or a suggestion on where to find something that might have a solution for this that would be of great help.
Thanks.
Setting up an "always hot" circuit
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Tim
- Shipwright Extraordinaire
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I'm not quite sure what the crux of your question is. How you actually proceed with an "always hot" distribution buss depends on how things are currently set up, and where things are or will be.
You can put this new buss anywhere. The idea is to run the hot lead to the buss from the hot lead of the battery switch--the terminal where the cable running from the battery positive connects. The closer the new buss is to the terminal from which it draws its power, the less worry about voltage drop and the (possibly) smaller the wire size you need. So plan to locate the new buss near your battery switch, wherever that is.
Distance from the house bank is irrelevant because you don't draw the power directly off the battery: it's coming from the hot side of the battery switch, which is typically in a more convenient location. You can provide the buss power directly off the battery, but the whole idea is to avoid multiple terminals on the battery studs, so it's best to avoid this if you can. Plus it reduces wire length (and voltage drop) in most cases if you come from the battery switch.
Wire size to the "always hot" buss depends on what you plan to attach to the buss, as well as the buss's distance from its power source (the battery switch, that is). For things like bilge pumps or stereo hookups, you're not talking about a lot of potential draw, so the wire need not be huge. Again, this will depend on your situation, so size the wire accordingly in any event. I typically use 8AWG for this run, which is overkill for the loads incurred in the installations I've done (a bilge pump and stereo), but it allows for realistic future expansion without concern.
Then, just wire your bilge pump through this buss; the hot buss will stand in for the positive battery terminal typically shown in a bilge pump wiring diagram. Use a switch for the bilge pump somewhere convenient or in the panel; add a separate fuse for the pump as indicated by the pump manufacturer. Or use your existing pump switch, if fitted.
If this doesn't answer your question, feel free to post more detail and I'll try again.
You can put this new buss anywhere. The idea is to run the hot lead to the buss from the hot lead of the battery switch--the terminal where the cable running from the battery positive connects. The closer the new buss is to the terminal from which it draws its power, the less worry about voltage drop and the (possibly) smaller the wire size you need. So plan to locate the new buss near your battery switch, wherever that is.
Distance from the house bank is irrelevant because you don't draw the power directly off the battery: it's coming from the hot side of the battery switch, which is typically in a more convenient location. You can provide the buss power directly off the battery, but the whole idea is to avoid multiple terminals on the battery studs, so it's best to avoid this if you can. Plus it reduces wire length (and voltage drop) in most cases if you come from the battery switch.
Wire size to the "always hot" buss depends on what you plan to attach to the buss, as well as the buss's distance from its power source (the battery switch, that is). For things like bilge pumps or stereo hookups, you're not talking about a lot of potential draw, so the wire need not be huge. Again, this will depend on your situation, so size the wire accordingly in any event. I typically use 8AWG for this run, which is overkill for the loads incurred in the installations I've done (a bilge pump and stereo), but it allows for realistic future expansion without concern.
Then, just wire your bilge pump through this buss; the hot buss will stand in for the positive battery terminal typically shown in a bilge pump wiring diagram. Use a switch for the bilge pump somewhere convenient or in the panel; add a separate fuse for the pump as indicated by the pump manufacturer. Or use your existing pump switch, if fitted.
If this doesn't answer your question, feel free to post more detail and I'll try again.
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Ronin120
- Rough Carpentry Apprentice
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Ah, now I understand. From the battery selector switch. I'm still working my way slowly through the Charlie Wing's book to try and get a better understanding as I start this project.
I don't know why I thought I had to pull cable from the house battery bank. Maybe because the existing bilge pump is wired directly off the starter battery and I couldn't get that out of my head. That battery is located under the navigation station seat, near the bilge pump so it must have been done that way for convenience.
Right now I have one small automatic pump but will install a larger one in the future so having the buss will be the way to go. I'll use the larger gauge wire as you advised. The current pump has an in-line fuse so that is okay.
Tim, thanks for helping me muddle through. Great advice, great work and a great forum.
Dave
I don't know why I thought I had to pull cable from the house battery bank. Maybe because the existing bilge pump is wired directly off the starter battery and I couldn't get that out of my head. That battery is located under the navigation station seat, near the bilge pump so it must have been done that way for convenience.
Right now I have one small automatic pump but will install a larger one in the future so having the buss will be the way to go. I'll use the larger gauge wire as you advised. The current pump has an in-line fuse so that is okay.
Tim, thanks for helping me muddle through. Great advice, great work and a great forum.
Dave