New Electrical System Questions

[SV Miss Fe]

I've recently purchased a sailboat. The electrical system is um "home built" and quite frankly a mess to say the least. So I'm in the process of diagramming everything out for replacement and have a few questions.

Currently the house bank is 4 Trojan T105 running at 12v (1 year old). I'd like to add two more T105's but I hear its bad to mix batts of different ages. Obiviously I'm not about to junk 4 almost new batteries. Do I have any options?

Once I'm confident with my diagrams I want to do use one of the deluxe panels from paneltronics. My theoretical max load (everything on at full power) is around 150 amps. Can I use a 100 amp panel since having everything on at once will never occur?

Currently there are two large 12+ switch panels one forward near the mast and one aft near the battery bank. There are also multiple 3-6 switch panels spread around the boat. In my mind its a 33' boat. I'll never be far from the main panel can I just put the vast majority of switches in one large panel?

Most panels seem to come with either digital or or analog meters. The boat came with a xantrex link 20 battery monitor. Can I use this and forgo the panel meters?

Assuming I'm using high quality circuit breakers and excluding sensitive electronics do I need to use fuses anywhere?

Thank you in advance for your help! This forum is an awesome resource.

[Emmalina]

Always plan a panel so everything can be switched on at full load IMHO and a reg in many countries. As for mixing batts have done in the past with no ill effects ! Good luck
Oh and forget fuses use magnetic/thermal breakers all available on ebay !

[Frankly]

I have installed a system similar to what you are aiming for on Cbreeze. 6 GC batteries 4 midships and 2 fwd in the bilge. No starting battery just live and start on the large house bank. Several points to consider:

1. The available fault current from this many GC batteries is probably in excess of the 5000 Amps interrupt rating of standard marine circuit breakers. Typically this is handled by installing ANL ot type T fuses before the circuit breaker panels.

2. I like the concept of multiple electrical panels spread around the boat feeding local loads. Each panel feed is protected by a high amp ANL fuse. I have 5 on Cbreeze.

3. I have always replaced all 6 batteries at a single sitting. If you protect all components and provide switches for all 3 sections, my best guess is having slightly different age batteries is not going to end the world.

4. I have a link 10 with a common shunt for all three banks and it is the device I typically use to check the condition of the batteries even though the original analog ammeter and voltmeter are staring me right in the face. Digital is just easier and more accurate.

5. If you have a way of opening an ACAD DWG drawing, then I could send you a wiring diagram. Don't think I still have a way to convert it to a pdf any longer.

Any other questions, fire away.


_______________

"And my Balmar is still putting out",

[Frankly]

Just looked up a couple of pages I removed from Oct/ Nov 2011 issue of "Profession Boat Builder Magazine". "Banks larger than a single 8D, a pair of GP 31s or six 6V GC batteries batteries should rely on Class T fuses for OCP " Steve D Antonio.

A second rule of thumb from the same article. 37 to 45 amps per lb at 12V. 6 GC battery bank puts this number in the 30,000 amp ball park.

I also fused and double insulated my 3GM starting circuit. 60 years of messing with this stuff has made me a little anal in my old age. Have seen the horrors of electrical systems gone awry also don't help.

" but my Balmar ....."

Frank

[StuM]

Originally Posted by Frankly

5. If you have a way of opening an ACAD DWG drawing, then I could send you a wiring diagram. Don't think I still have a way to convert it to a pdf any longer.

Here's an online converter that either of you could use:

DWG to PDF | Zamzar - Free online file conversion

[SV Miss Fe]

Originally Posted by Frankly

I have installed a system similar to what you are aiming for on Cbreeze. 6 GC batteries 4 midships and 2 fwd in the bilge. No starting battery just live and start on the large house bank. Several points to consider:

1. The available fault current from this many GC batteries is probably in excess of the 5000 Amps interrupt rating of standard marine circuit breakers. Typically this is handled by installing ANL ot type T fuses before the circuit breaker panels.

2. I like the concept of multiple electrical panels spread around the boat feeding local loads. Each panel feed is protected by a high amp ANL fuse. I have 5 on Cbreeze.

3. I have always replaced all 6 batteries at a single sitting. If you protect all components and provide switches for all 3 sections, my best guess is having slightly different age batteries is not going to end the world.

4. I have a link 10 with a common shunt for all three banks and it is the device I typically use to check the condition of the batteries even though the original analog ammeter and voltmeter are staring me right in the face. Digital is just easier and more accurate.

5. If you have a way of opening an ACAD DWG drawing, then I could send you a wiring diagram. Don't think I still have a way to convert it to a pdf any longer.

Any other questions, fire away.


_______________

"And my Balmar is still putting out",

Frankly,
I can definitely work with autocad files if you don't mind sending them it would be greatly appreciated. My main issue with multiple panels is one I'm not very familiar with the boat and two the labeling is terrible so its when I wanna make something turn on. There's literally a switch labeled "emergency" and I'm afraid to try it until I trace the wire. I think it probably makes sense to run two panels though since 50 and 100 amps seem the norm and one of each should meet my needs.

[Bill_E]

A few comments: First, check out MaineSail's articles. (Compass Marine How To Articles Photo Gallery by Compass Marine How To at pbase.com) They will give you lots of background. Second, all fusing and circuit breakers are mainly to protect your wires. So, if you have a source (battery, etc) capable of 200 amps then you need a 200 amp fuse or circuit breaker within a very short cable distance of that source. And, you need wires or cables capable of handling the current. And, finally, beware that there can be significant voltage drop in long cables. I found that the wiring from the panel to my VHF radio was long enough and thin enough that when I was transmitting, the voltage could drop low enough to cause the radio to drop out. (That's how the previous owner had wired it.) I had to increase the wire size (decrease the gauge) to make it work consistently.

I've installed heavier cables (wires) and buss bars and lots of fuses as well as having three panels.

Bill

[GordMay]

Greetings and welcome aboard the CF, Miss Fe.

[Frankly]

not a great PDF but the price was right.



Added a picture of the high amp fuse block to my albums, this is the heart of the system, home built, but not a big deal if you have a drill press.

[exMaggieDrum]

BattWiring1.xls

ACWiring1.xlsI completely rewired my previous 42' and currently rewiring my 44'. I have completely rewired a couple of other boats as a tech, and done many battery systems (AC only, DC battery, new panels, etc.).

It is a pretty big job. If you have a 33' it is easier. If it were me I would break it up in to pieces and do one at a time. I'm doing my major battery cables now - house, start, switches, inverter/charger, etc. You could do that and leave the DC panel for later, or you could do the DC panel first. Whether you have remote panels or not is up to you. I wouldn't on a small boat but the other poster has it and it works for him. I like centralized control but some switches will be local, as will some fuses and sub-terminal strips. All wires fused by size etc.

You can actually put in a new panel without changing the existing wiring. Put in long terminal strips - one terminal for each branch circuit. Lead the old wiring to these strips. And then put in the new panel and stub the panel circuit breakers to the new strips. Later you can replace or mix and match the branch circuits at your leisure (hah!). If you want to split circuits to new breakers just add more terminals. This is a good way to wire a new boat as it allows you to make really tidy leads to your panel.

Usually you don't have as many AC circuits but you can do it this way too but you need to shield the hots at least.

I would just use the digital meter you have and/or put in new or additional. No need for meters on the panel. This way you can change meters in the future without figuring out how to get ones to match your panel. I would consider the Blue Sea panels too if you haven't, but Paneltronics are very good too.

But the other posters advice for correct fusing is a must. Good tinned marine wire. Label everything. I love diagrams!!! And follow good wiring protocols - drip loops, proper crimp terminals. Get a good quality crimper and only the best tinned terminals. Secure your wires close to where they terminate and along their paths. Use chafe protection. Etc etc. Not trying to insult you as you may already know all this. Just in case.

It's a big job even on a small boat but you will be so happy (and so poorer) after it is done. I've attached a couple of drawings I did using MS Excel's drawing functions. If you have autocad you are set for that.

[Victory 28]

I usually only get through a few sentences before reaching the same conclusion on DC power system question posts, most all of the people making design decisions on these systems are very nearly clueless and when I work on these systems I am astounded at the things I see with my meter, termination methods, wire gauge, circuit protection device specs etc., it is more than just hit or miss, it is a fantasy world for a lot of these people. My favorite experience as of late was a boat owner and the crew member who suddenly decided the battery was being dangerously overcharged from the wind turbine, his solution: jam a boat hook into the turbine blades in 20k winds which broke 2 of the blades! After examining a few things I asked him why in the world he thought the battery was being damaged and how much voltage or current did he actually witness, the guy could not answer even a single question intelligibly other than to say that "he just knew...." I informed the skipper that based on the capacity of his lead acid battery bank at 450AH and the absolute continuous maximum output of 36 amps from the turbine (even into a zero impedance) that it would take several days minimum at continual wind speeds well over 25 knots before the battery would even approach an equalization voltage and this w/out any regulation. I made the decision to just get out of there when they disagreed with me. No charge.

[Stu Jackson]

Originally Posted by Bill_E

A few comments: First, check out MaineSail's articles. (Compass Marine How To Articles Photo Gallery by Compass Marine How To at pbase.com) They will give you lots of background.

Bill's right. And, you can save the $ buying a book, dpending on how you like to learn.

Try this, too, it includes some links to Maine Sail's site. Includes basic wiring diagrams, fuse and wire sizing links, etc.

Electrical Systems 101 Electrical Systems 101


There's one of our skippers going through this for his boat right now that you may find of some interest. Good luck.

1987 MK 1 Electrical System Upgrade - Feedback Requested

[jeepbluetj]

Read Maine Sail's articles.

Fuse within 7 inches of the battery bank. This fuse is sized to protect the wire and panels it's feeding.

Then standard breakers for the panels (unless it's a metal boat).

I used the standard paneltronics panels when I rewired my boat. Liked them quite a bit. I'm sure blue sky or a custom panel would be nice too.

Single panel vs multiple? Depends on how hard it is to get wiring to where it's going. I moved my 110v out of my 12v panel. It was shorter runs, got the two completely isolated, and there was a spot for it. I only have 1 12v panel just like when catalina built the boat. It does, however, no longer have the disaster of wiring behind it that the boat had when I bought it. I used ANL fuses.

I just finished rewiring a 20' skipjack. Being a powerboat, the batts are in the back and the fuses are up at the wheel. There were NO battery fuses, NO bilge pump fuses, etc.. So there's now MRBF fuses at the batteries. A new perko switch. Breakers in the back for bilgepump, etc.. And fuses for the trim pump and the feed to the dash (where there is actually fuses for the branch circuits.

You will never blow the big battery fuse unless something is horribly wrong. But if it ever goes that wrong you don't want the battery cable being the fuse. A friend has a little 16' or so fishing boat, he was working on it, and one of the bonding cables on the outboard caught on fire. Luckily that was the only damage. And nope - not a fuse to be found on the boat. Problem ended up being an accidental energizing of the steering cable and the shortest path was through the engine. It'll be my next rewire.

[SV Miss Fe]

Originally Posted by jeepbluetj

Read Maine Sail's articles.

Fuse within 7 inches of the battery bank. This fuse is sized to protect the wire and panels it's feeding.

Then standard breakers for the panels (unless it's a metal boat).

I used the standard paneltronics panels when I rewired my boat. Liked them quite a bit. I'm sure blue sky or a custom panel would be nice too.

Single panel vs multiple? Depends on how hard it is to get wiring to where it's going. I moved my 110v out of my 12v panel. It was shorter runs, got the two completely isolated, and there was a spot for it. I only have 1 12v panel just like when catalina built the boat. It does, however, no longer have the disaster of wiring behind it that the boat had when I bought it. I used ANL fuses.

I just finished rewiring a 20' skipjack. Being a powerboat, the batts are in the back and the fuses are up at the wheel. There were NO battery fuses, NO bilge pump fuses, etc.. So there's now MRBF fuses at the batteries. A new perko switch. Breakers in the back for bilgepump, etc.. And fuses for the trim pump and the feed to the dash (where there is actually fuses for the branch circuits.

You will never blow the big battery fuse unless something is horribly wrong. But if it ever goes that wrong you don't want the battery cable being the fuse. A friend has a little 16' or so fishing boat, he was working on it, and one of the bonding cables on the outboard caught on fire. Luckily that was the only damage. And nope - not a fuse to be found on the boat. Problem ended up being an accidental energizing of the steering cable and the shortest path was through the engine. It'll be my next rewire.

So my boat is steel... whats the compatibility issue with metal and standard breakers your referring too?

[SV Miss Fe]

Originally Posted by exMaggieDrum

Attachment 112798

Attachment 112799I completely rewired my previous 42' and currently rewiring my 44'. I have completely rewired a couple of other boats as a tech, and done many battery systems (AC only, DC battery, new panels, etc.).

It is a pretty big job. If you have a 33' it is easier. If it were me I would break it up in to pieces and do one at a time. I'm doing my major battery cables now - house, start, switches, inverter/charger, etc. You could do that and leave the DC panel for later, or you could do the DC panel first. Whether you have remote panels or not is up to you. I wouldn't on a small boat but the other poster has it and it works for him. I like centralized control but some switches will be local, as will some fuses and sub-terminal strips. All wires fused by size etc.

You can actually put in a new panel without changing the existing wiring. Put in long terminal strips - one terminal for each branch circuit. Lead the old wiring to these strips. And then put in the new panel and stub the panel circuit breakers to the new strips. Later you can replace or mix and match the branch circuits at your leisure (hah!). If you want to split circuits to new breakers just add more terminals. This is a good way to wire a new boat as it allows you to make really tidy leads to your panel.

Usually you don't have as many AC circuits but you can do it this way too but you need to shield the hots at least.

I would just use the digital meter you have and/or put in new or additional. No need for meters on the panel. This way you can change meters in the future without figuring out how to get ones to match your panel. I would consider the Blue Sea panels too if you haven't, but Paneltronics are very good too.

But the other posters advice for correct fusing is a must. Good tinned marine wire. Label everything. I love diagrams!!! And follow good wiring protocols - drip loops, proper crimp terminals. Get a good quality crimper and only the best tinned terminals. Secure your wires close to where they terminate and along their paths. Use chafe protection. Etc etc. Not trying to insult you as you may already know all this. Just in case.

It's a big job even on a small boat but you will be so happy (and so poorer) after it is done. I've attached a couple of drawings I did using MS Excel's drawing functions. If you have autocad you are set for that.

exMaggieDrum,
Thank you very much for the information. I'm not a complete newbie to wiring per say I've done several smaller boats, plenty of stereos, computers, micro controller for a fish tank and some light residential. This is by far my most ambitious project yet. However many people are completely new and this is good information for them. I'm dealing with lots on non-tinned poorly terminated sometimes undersized wire so after talking with my surveyor we agreed its all going away sooner rather than later though some things like the mast wiring I'll keep original wiring until for example I lower the mast.

I'm also giving this project several months since the boat is on the hard and interior mostly cleaned out for winter and it has a diesel heater so I can comfortably work on it throughout the winter. I am kinda lucky in that the boat is fairly simple with no bow thruster or windless (manual ).

I guess I should clarify that I don't have a copy of autocad on my computer but I work for an engineering firm (I am not an engineer by any stretch though) so I can get anything I need converted.