Electrical Panel

[hilbert]

As the weather has gotten colder, I've gone back to rewiring the boat.
I have added a screw terminal for every connection and a fuse for every circuit.






edit made on 27MAY2014 to fix image links

[Ron M.]

That photo of the 'rats nest' brings back memories of my boat when I first brought it home.
Nice job cleaning it up.

[shinchman]

I have recently acquired a CD 27 that largely needs to be rewired. Space is at a premium. I notice that you do not have a master breaker, even though you appear to have space. Or do you have a fuse hidden away in the panel? Any thoughts on need to include a master breaker between the battery selector switch and the branch breakers? Thanks in advance for any advice.

Steve (new owner of unnamed CD 27)

[hilbert]

I didn't include a master fuse (or breaker) between the battery selector switch and the Blue Sea's Fuse Block on the back of the panel.
I suggest that you think it through and decide on the benefits of a master breaker for your boat.
In my case, it is very unlikely that the sum of the all the circuits on the panel will ever exceed the upstream wiring capacity.
I went one size larger on all my wiring calculations and the smallest wiring anywhere in the panel is 10 AWG.
The connection between the battery selector switch and the fuse block is only about 7 inches of 8 AWG wire.



There is a terminal fuse on batteries:


Good luck with your new (and yet to be named) boat.

edit made on 27MAY2014 to fix image links

[shinchman]

That is an elegant solution.

I am assuming you have a dedicated house battery, as I do (mine is Series 31 AGM, 1000 MCA, 105 Ah). I am curious what size & type terminal fuse you calculated for. Based on your switches, it appears we have very similar house loads. I am thinking 100 amp is correct for my house load (7 house lights, 2 nav lights, mast & deck lights, pilot, gps, depth, vhf, stereo, 2 bilge pumps, spare/outlet). My question is, because the same cable is also used for charging the battery, whether a 100 amp terminal fuse is too small for periods when the alternator is charging the battery (particularly when deeply discharged). I am seeing in the literature fuse ratings more in the 250-400 range - but I can't tell exactly how one sizes circuit protection for charging situations.

If so, would the proper solution be a larger terminal fuse on the battery (sized to alternator output) and a smaller in-line fuse between the battery selection switch and the distribution panel (sized to house loads)? I only want to do this once, and to get it right, without overkill.

For the cranking battery I have tentatively sized a terminal fuse at 300 amp, slow burn.

[hilbert]

My question is, because the same cable is also used for charging the battery, whether a 100 amp terminal fuse is too small for periods when the alternator is charging the battery (particularly when deeply discharged). I am seeing in the literature fuse ratings more in the 250-400 range - but I can't tell exactly how one sizes circuit protection for charging situations.

I don't know what engine or alternator is in your CD 27, but I would be surprised if it could output more than 50 amps.


This is how I am wiring my boat:
There will be two "banks", a cranking battery and house batteries (two golf cart batteries at ~ 230Ah).
Each bank has it's own bus bar. The banks can be combined by the the battery switch on the DC distribution panel or a Blue Seas Automatic Charging Relay, ACR.

The starter and alternator do not go through the DC distribution panel. They are connected directly to the cranking bus bar by way of a separate battery switch.
In this way, the path to the cranking battery is more direct and the alternator diodes can not be damaged by inadvertently turning the battery switch off, on the DC distribution panel.

Here is the wiring diagram:


I am using 125A fuses on the positive terminal of the battery banks for a few reasons:
1) The ACR is rated at 120 amps.
2) The starter is rated at 1000 watts nominal. Even if the voltage were to drop to 10 volts, this would draw only 100 amps. So I gave it another 25% to avoid the inconvenience and expense of a blown fuse. In practice, the current is far less than 100 A.
3) The alternator is rated at 55 amp (maybe only 30 - 35 amp max in real world operating conditions and this normally drops quickly as the the internal resistance of the wet cell batteries rises during charging).
4) All the wiring is sized to withstand at least 250 amps for the time it will take a fuse to blow.
5) The purpose of the terminal fuses is mainly to protect against a dead short.

Bus bars and ACR (not fully wired in this picture):


Battery switch for engine and new engine wiring in progress:


edit made on 27MAY2014 to fix image links

[Russell]

What did you use for wire labels? Looks like some sort of shrink tube labels? I spent a couple hours today putting together a shopping list for my panel rewire (inspired my Kens unfortunate experience, its something I have put off far too long anyway). Trying to find a good solution for wire labeling and havnt found anything I really love, in the past i have just used white electrical tape and a sharpie pen. But since i can barely read my own writing I do not want to go that route, label makers are spendy though.

[hilbert]

What did you use for wire labels?

I printed wiring labels and put them under clear heat shrink tube. I also like to keep wiring diagrams in a binders.
It is easier to see the big picture when looking at a drawing of a terminal block:


I purchased most of the marine wire and electrical items from GenuinedealZ, http://shop.genuinedealz.com/.
The quality and prices are good, the shipping is free and Mike has always replied to my emailed questions.

edit made on 27MAY2014 to fix image links

[mashenden]

What did you use for wire labels? Looks like some sort of shrink tube labels? I spent a couple hours today putting together a shopping list for my panel rewire (inspired my Kens unfortunate experience, its something I have put off far too long anyway). Trying to find a good solution for wire labeling and havnt found anything I really love, in the past i have just used white electrical tape and a sharpie pen. But since i can barely read my own writing I do not want to go that route, label makers are spendy though.

Hi Russell, I enjoyed talking on Sunday across from the Bean. Please share the details on your choice of panels and their locations. As mentioned, I too will be doing a similar project... and some woodwork... and some major cleaning:) I have not yet decided on what the layout will be but separate panels for AC and DC seems likely.

BTW, the upholstery is coming clean by washing machine. That's a load off my plate.

[Russell]

What did you use for wire labels? Looks like some sort of shrink tube labels? I spent a couple hours today putting together a shopping list for my panel rewire (inspired my Kens unfortunate experience, its something I have put off far too long anyway). Trying to find a good solution for wire labeling and havnt found anything I really love, in the past i have just used white electrical tape and a sharpie pen. But since i can barely read my own writing I do not want to go that route, label makers are spendy though.

Hi Russell, I enjoyed talking on Sunday across from the Bean. Please share the details on your choice of panels and their locations. As mentioned, I too will be doing a similar project... and some woodwork... and some major cleaning:) I have not yet decided on what the layout will be but separate panels for AC and DC seems likely.

BTW, the upholstery is coming clean by washing machine. That's a load off my plate.

I am still in Oriental waiting on some pieces to come in, but I plan to do some detailed posts about the rewire once i get it going. I already took some "before" photos, which I am almost embarrassed to show (its the previous owners on top of poor origonal CD wiring, then me adding too it, its bad).

Glad to hear the upholstery cleaned up, bigger concern will be the foam (thats the expensive part!), and it takes so long to dry once wet, lug it up to your house in VA and keep soaking it and rinsing it all summer. I hope you take a lot of photos and show us all the progress of the project, I have no doubt that the boat will be great once again. Seriously look into a ozone generator, I think that alone will do more to desmoke the boat then anything else will.

[mashenden]

I am still in Oriental waiting on some pieces to come in, but I plan to do some detailed posts about the rewire once i get it going. I already took some "before" photos, which I am almost embarrassed to show (its the previous owners on top of poor origonal CD wiring, then me adding too it, its bad).

Glad to hear the upholstery cleaned up, bigger concern will be the foam (thats the expensive part!), and it takes so long to dry once wet, lug it up to your house in VA and keep soaking it and rinsing it all summer. I hope you take a lot of photos and show us all the progress of the project, I have no doubt that the boat will be great once again. Seriously look into a ozone generator, I think that alone will do more to desmoke the boat then anything else will.

I definitely will take pics. I think I got you beat on wiring messes You have a distinct advantage of being able to easily figure out what wires go to what.

Surprisingly, the foam is not overly smokey. I can smell Frebreeze and in some places a faint smokey smell if I really take a drag. Other places I can smell the old Perkins. Then I stopped sniffing when I realized what has been on these seats. That all said, I am telling myself that a boat this age will have smells, whether they be smoke, diesel, or the funky waste tank smell. I just don't want to put them back on board until I have thoroughly cleaned the boat. I will definitely be looking into the ozone generator.

BTW, today we formally exchanged final payment so Parfait is mine. Wohoo!!!!. I'll have to post something on the Parfait post later.

[tjr818]

I am using 125A fuses on the positive terminal of the battery banks for a few reasons:
1) The ACR is rated at 120 amps.
2) The starter is rated at 1000 watts nominal. Even if the voltage were to drop to 10 volts, this would draw only 100 amps. So I gave it another 25% to avoid the inconvenience and expense of a blown fuse. In practice, the current is far less than 100 A.
3) The alternator is rated at 55 amp (maybe only 30 - 35 amp max in real world operating conditions and this normally drops quickly as the the internal resistance of the wet cell batteries rises during charging).
4) All the wiring is sized to withstand at least 250 amps for the time it will take a fuse to blow.
5) The purpose of the terminal fuses is mainly to protect against a dead short.

I too am in the planning stages of rewiring our CD27. I am really impressed by the neatness of your work. How are those 125A terminal fuses working out. I would like to go with as low a rating as practical. I was planning on 100A for the house battery, but don't know what to go with for the cranking battery. Is the 125A enough?

[hilbert]

How are those 125A terminal fuses working out. I would like to go with as low a rating as practical. I was planning on 100A for the house battery, but don't know what to go with for the cranking battery. Is the 125A enough?

Being in the middle of a long restoration, I have put little load on the 125 amp fuse.

Once the boat is in the water, I will find out what the normal current is for the starter.
I would be surprised if the starter draw approached the nominal 1000 watt rating, expect under extreme conditions.

For what its worth, I thought 125 amps was more than adequate for the cranking battery of my 16HP engine.