Small Boat Electrical for Sail

[john61ct]

All sensors should be attached directly to the bank.

I've read temperature ones can be to the batt body, thermal conducting paste.

All Power lines can be consolidated to buss bars and panels.

Big amps requires more robust infrastructure, but quality wire and fittings, well-crimped termination should be standard.

Just one power wire to the post, CP and master isolating switch, ideally within 7" of the post.

Always-on loads, before any remote switches / automated relays.

From there branch off to high-amp devices, maybe subsidiary buss bars and your load panels.

CP on the source side of all wires, sized to protect that gauge, or lower.

[rgleason]

Thanks John, hope my diagram does much of this but I think it fails in a couple of points.

Originally Posted by john61ct

Just one power wire to the post, CP and master isolating switch, ideally within 7" of the post.

Is the 50a Main DC Panel Breaker a "Master Isolating switch" ?
or is it something else?

Originally Posted by john61ct

From there branch off to high-amp devices, maybe subsidiary buss bars and your load panels.

Are you suggesting a different arrangement than what the attach diagram shows? If so, I am not following it well.

Originally Posted by john61ct

CP on the source side of all wires, sized to protect that gauge, or lower.

I am realizing that the diagram has an unprotected circuit located on the "C" of the 12Both Switch including:

• DC Panel (50a) less than 3' from bus to Panel
• Starter (64a) this is longer perhaps 7'
• Total amps 115a
• Using Blue Sea for 6' I get #4 wire
• Recommended to size up one, so #1 wire.
• The fuse should be 150a and there should be two of these located on the main Pos Bus for Bat #1 and on the second pos bus for Bat #2
• Is this correct?

All Power lines can be consolidated to buss bars and panels.

Does this include power/sensing wires + and - from the ARS-5 Regulator?



Thanks very much.

[rgleason]

Stu, I've made those changes to the sensors and have relabeled.
Also I have tried to correct the unprotected wires from the Pos bus up to the switch, realizing that they are carrying two loads the Panel at 50a and the Starter at 64a. I did the Blue Sea calc for this and it was AWG 4, so I increased size to AWG1. I also added two 150a pos bus fuses.
Does the cable to the DC Panel on the Common side of the switch have to be #1 or can it be sized for the 50a breaker and be #8?

Also the Starter supposedly needs 64 amps according to Yanmar, which would require a #6 wire normally, but perhaps it too should be #1 to be protected by the 150a fuse. I suppose I could put more fuses up at the "C" on the switch and drop the wire size down then, but this is getting kind of ridiculous.


Also I've read somewhere that the Alt does not need a fues.

I'd like to get this as simple as possible with as few fuses and bus bars as possible, but it needs to be a safe installation. John said something about using good wire and connectors and that bus bars and fuses are for high loads. Do I have high loads? I don't know where or how I am going to fit all this wiring yet....it is a small boat and there are not many closets or big surfaces left in that area...so simpler is better.

I've used a black pen instead of gray and enlarged it a bit by removing the fuse-wiring. The PDF is probably the best for viewing.

[Stu Jackson]

rg,


Starter load and fusing:

Engine Starting Loads - Amp Draw Data (by Maine Sail)

http://forums.catalina.sailboatowner...d.php?t=102027


Dare I suggest again that you at least read the "headlines" in the Elec. System 101 topic, most everything is there.


DC Panel: Don't know where you got 50A from. Even if I ran EVERYTHING DC on my boat at the same time (macerator pump, shower pump, bilge pump, all my lights --- ALL of them including running, steaming, deck and interior, which would never happen anyway, you get the picture, I'd be only close to 30A. You have to determine realistically what your maximum load will be. 50A is for a huge boat. Unless you have a DC watermaker...


Wire sizes: No way to answer because I don't know your wire lengths. You do have some strange different wire sizes on the "same" feed lines (i.e., 1/0 house bank to + bus, #4 to 1-2-B, #8 to the DC panel).



Fusing in general: Think of your batteries as big bombs just waiting to explode. THEY are the SOURCE of any power if something goes belly up in the wiring or the equipment. The only thing I can see that you haven't already fused is from the banks to the 1-2-B. Noodle around some more in 101 and Maine Sail's website, I'm sure he discusses this, too.

[rgleason]

Stu, thanks

rg,
Starter load and fusing: Amp Draw Data (by Maine Sail)
http://forums.catalina.sailboatowner...d.php?t=102027

Yes, that is the 64a for 3YM30. Its a small motor.

Dare I suggest again that you at least read the "headlines" in the Elec. System 101 topic, most everything is there.

I do, but I get lost reading and learning.

DC Panel: Don't know where you got 50A from.

That's my main panel breaker, it is within less than 2' of the 12Both Sw.
No DC watermaker. Isn't that breaker protecting something? I installed a Paneltronics in 1995. No big picture understanding at the time.

Wire sizes: No way to answer because I don't know your wire lengths.

Estimated lengths are at the end of the wire size notations.

You do have some strange different wire sizes on the "same" feed lines (i.e., 1/0 house bank to + bus, #4 to 1-2-B, #8 to the DC panel).

Yes, thanks for noting. I need fuses there, and have added them, but I am confused if I should include full load of the DC panel or some allowance for "load diversity". Perhaps I should replace the breaker with a 30a? Its acting like a fuse isn't it, protecting the main wiring in the panel?

Fusing in general: Think of your batteries as big bombs just waiting to explode. THEY are the SOURCE of any power if something goes belly up in the wiring or the equipment. The only thing I can see that you haven't already fused is from the banks to the 1-2-B.

Yes, the new diagram has fuses now, but it is still not right. Will check out Elect 101, that's all I've been doing and get lost reading.

Ward H here, has the same size batts (2) 2GC 6v so his diagram looks pretty complete but with longer runs. Should I look this over?

RE Wire Sizes from earlier delete message
The wire lengths are estimated and in the drawing but I don't expect you to do that stuff.

About the different wire sizes, I am realizing I have to work from the battery out, doing the wire size for "ampacity" using the Blue Seas calc, and then get the right size fuse for the end of the wire closest to the battery that will protect the wire by blowing before the wire blows.

For things like Alternators, Chargers and Solar that are shooting voltageXcurrent=power back to the battery, I guess you size the wire for that load and fuse it away from the battery?

For things like Starters that draw a large load (64amps is the startup amps for a 3YM30 I believe) from one of the batteries, through the "C" terminal on the switch it is just like the other loads and the wire gets sized as I have done and the right fuse is put at the battery end.

The issue is that there are two loads on the "C" 12Both, House and Starter. Do we have to assume that both loads are used at full capacity? Or are we permitted to consider some load diversity for the DC Panel at least? The reason I ask, is it might increase all those cable sizes because they are joined loads on the same fuse at the battery.

I am just trying to understand the method and learn how to do this, so once I get the measurements and full existing diagram, I can do it. I've shown what I think the distances are.

Thanks.

[john61ct]

Originally Posted by rgleason

"Master Isolating switch"

Up to you. On a big bank for safety, emergencies or while servicing, isolates bank from all wires. Only the CP is between it and the bank.

> Does this include power/sensing wires + and - from the ARS-5 Regulator?

Sensing wires are dedicated, carry no power output.

If combined only, I'd want it directly on the bank, but that isn't always practical.

[rgleason]

This is the battery bank, I'd like to have, but the only way to get it is split it in half and put it in the Port and Starboard cockpit locker. I really like the sideways fuse connectors because it saves much needed space (inches count).

[Stu Jackson]

rg,

Ward "learned everything he knows" from the same material I've been sending to you! He read my 101 and Maine Sail's stuff and had at it. Nice guy. Good stuff to emulate. So did Bob S who had a Catalina before he bought his Beneteau - I helped him with his wiring diagram on his old boat offline by email and gave him the same material. You CAN do it!

50A panel breaker? Are you sure this is the DC side? Something sounds wrong. 50A could be your AC shorepower breaker. There is rarely a big breaker on the DC side, just your 1-2-B switch to individual breakers on the DC panel feeding the loads.

>>>The issue is that there are two loads on the "C" 12Both, House and Starter. Do we have to assume that both loads are used at full capacity? Or are we permitted to consider some load diversity for the DC Panel at least? The reason I ask, is it might increase all those cable sizes because they are joined loads on the same fuse at the battery.

rg, try this reasoning: you may have your fridge ON when you start your engine. You MAY have your fridge and running lights on when you start your engine. So, yes & no: diversity on the DC panel loads as I mentioned before; but then you get to play a numbers game: read Maine Sail's discussion of starter amp loads, then add your worst case loads from the DC panel. What I'll bet you'll find is that if you compare that "diversified panel load" to the starter load PLUS a FULL 30A panel there may well be NO difference in wire size anyway because wire is only made in certain sizes, right? They don't make #3 wire, for example. So if you're "close" on one wire size you end up using the next bigger one anyway. Maine Sail often reminds us that connection losses can well make up at good percentage of line loss drops, so if you're using the 3% tables, for sizing the wire based on load and distance, you should add 10% or so to the load or the distance (I forget his exact numbers, but it's in there somewhere...). It IS a balancing act. But if you "run the numbers" both ways, you may find no difference in the wire sizes at all by the time you're done. Another way to say this is that the starter load in itself may determine the wire size (based on distance) that will be, in itself, a big enough wire to handle even the additional DC panel load because any given wire size can handle a RANGE of loads.



That's why they call it engineering.

And that's why us engineers are so crazy.


I always liked WM's wire sizing CHART in full living color, but it doesn't appear in their Advisors anymore, replaced by tables. Pity... It made the "range" more understandable to laymen. Like most of us, since none of us was a born electrician (you've heard me say that before, right?)



This has been a pleasure working with you. I'm off on a week long cruise tonight, so may not be in touch regularly for that period of time. Our islands have spotty coverage at best, and unless I'm in a harbor (first two and last two nights) I'll be out on the hook & it will be a real "getaway."


Good luck, johnct is always here to help. If he gets too cryptic , let him know and I'm sure he'll start writing in English or point you to where you need to go.


Have fun.

[Stu Jackson]

Originally Posted by rgleason

>>>>>>>>>>>>
I do, but I get lost reading and learning.
>>>>>>>>>>>>>>>>>>>...................

I hear you.


One technique that I've used for dense/new/detailed information from the internet is to PRINT OUT those topics are parts of them that I need to really STUDY. HA, and here you thought high school was over, didn't ya?!?


I stuck many of them in my boat electrical 3 ring binder. And still refer to them even years later.



I can also annotate them and make notes in the margins.


The C34 forum pages are easy to print out using the print button on the forum screen, not a menu (i.e., File, Print, etc.), it converts it visually to print on white paper, rather than the gray you see on the screen. Please note that pictures do NOT come along with it, so either use a screen shot or copy the pictures and rename 'em and save them on your hard drive. I save the print to a word processing file and print from there.



Enjoy.

[rgleason]

Stu and John, thank you for all the help navigating the forum and informing me. There is still lots to learn and I am sure I'll be back here again. Stu have a great cruise in the islands. I sailed Antigua to Vero B. recently on a friend's boat.


Attached is another revision, along with a list of notes. Sort of the current status or points that need to be worked on with more info from the boat itself.

MaineSail Diagram (Stu you were right about info in Electrical Systems 101, this diagram is a good starter reference)
https://forums.sailboatowners.com/in.../#post-1332240

1. SI-ACR red voltage sense (fused) goes to the Starter so it has power all the time. The Switch "C" post is closer. Why not there?
2. SI-ACR black voltage sense (fused) goes to neg bus common to both batts. (as shown)
3. House DC Panel shows a fuse, doesn't the 50a House DC Panel act like a fuse, protecting inside the panel and outside? Stu I designed and installed the panel, I did not know what I was going to end up with for equipment. The old panel was a total mess. I decided I wanted a breaker to turn the entire panel off when not aboard. I can change that breaker if necessary.

4. The reserve bank shows no pos bus, just two fuses attached at right angles to the batt. How is this done?
5. Emergency Switch to Disconnect Bat #1 incorporated. If the Switch is within 7" of the Battery it can have the Battery Fuse too.
6. The Maine Sail diagram does not appear to have an Alternator fuse, perhaps I can remove that.

7. Is the Fry Alternator by turning through "Off" fixed? - Remove Zap-stop now?
7. If I really want a 450ah bank, now is the time to do it, as wire sizes and fuses will change.
8. Need to decide on batteries first, then measure wire distances and create as-built diagram.

[rgleason]

Attached is a PDF of the existing electrical system along with photos of the port and starboard lockers and the engine area.

On the port side inside the cabin in addition to the 1 Both 2 switch, below that is the Balmar ARS-5 and the refrig is under the counter. with VHF above.

On starboard side interior is a hanging locker with the isotherm hot water heater in the bottom and our Ozifridge unit mounted on the outboard side. I wll try to find a good photo.

[Stu Jackson]

Originally Posted by rgleason

Stu and John, thank you for all the help navigating the forum and informing me. There is still lots to learn and I am sure I'll be back here again. Stu have a great cruise in the islands. I sailed Antigua to Vero B. recently on a friend's boat.


>>>>>>>>>>>>>>>>>>

MaineSail Diagram (Stu you were right about info in Electrical Systems 101, this diagram is a good starter reference)
https://forums.sailboatowners.com/in.../#post-1332240

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
3. House DC Panel shows a fuse, doesn't the 50a House DC Panel act like a fuse, protecting inside the panel and outside? Stu I designed and installed the panel, I did not know what I was going to end up with for equipment. The old panel was a total mess. I decided I wanted a breaker to turn the entire panel off when not aboard. I can change that breaker if necessary.

>>>>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>
6. The Maine Sail diagram does not appear to have an Alternator fuse, perhaps I can remove that.

7. Is the Fry Alternator by turning through "Off" fixed? - Remove Zap-stop now?
7. If I really want a 450ah bank, now is the time to do it, as wire sizes and fuses will change.
8. Need to decide on batteries first, then measure wire distances and create as-built diagram.

Glad to help, always. I am sailing in the Gulf Islands of Canada in British Columbia. Having a great time, the Catalina Rendezvous starts today.


The diagram you pulled up is one of many by Maine Sail. This one is particularly good because of his idea of using pictures of actual equipment, it's pretty nifty. The "downside" of it is that unless you fully understand the CONCEPTS of house bank connected to AO, it could be confusing. Please, please, please read the other wiring diagram links in Elec 101. They don't include pictures, or fusing (which is a separate subject anyway) but they do show the BONES of how stuff works and explains the WHY of the improvements.



3. Understood. But a 50A fuse isn't going to protect anything if your load can't ever get that big. Think about it...


6. Sure it does. It's at the battery end where it belongs. It protects the wire.


7. Yes, if the AO goes to the house bank. That's the basis for the entire concept.


7. Why would that be. You could put in a zillion amp hour house bank, but that WOULD NOT CHANGE the wire sizes for the LOADS you have connected to it.


8. Good idea.


rg, I'm sure by now you've had a chance to absorb more of the links. Good luck, keep us posted.

[rgleason]

Stu, hope you enjoy the rendezvous.

3. House Panel - "a 50A fuse isn't going to protect anything if your load can't ever get that big. Think about it..."

I think it gets worse than that, the house panel has two old stiff #8 red & black wires going to it with a longer run than 6'. I think wires these should be replaced with something bigger and the breaker changed to 30a. My calcs show Panel at 50a requires #8 with a 70a fuse.

6. Alternator Fuse "Sure it does. It's at the battery end where it belongs. It protects the wire." I'm puzzled, the Alternator is a Source pushing current via higher voltage, into the batteries. How would a fuse at the opposite end of the alternator protect the wire? ..or is the fuse protecting the wire from the battery zapping things?

7." Yes, if the AO goes to the house bank. That's the basis for the entire concept."
Ok, just wanted to be sure, there is no way to easily switch the alternator + except through rewiring.
A. What harm does the zapstop do if left in place?
B. How about this concept? One Bank only, no combiner, no switching really except off. The reserve battery is stored in my tool locker main cabin, port side aft. Perhaps like this, Jump n Carry?
Then fill the old reserve area up with addition (2)T105 wired into the single bank.

"7. Why would that be. You could put in a zillion amp hour house bank, but that WOULD NOT CHANGE the wire sizes for the LOADS you have connected to it."
Wouldn't the alternator wiring change and perhaps if I were to use the starboard reserve for (2)T105, I would need bigger cables going there. I guess the other loads would not change.

"8. Good idea." Existing Drawing & photos are attached below.

[rgleason]

I was considering doubling the 225ah to 450 ah, with loads of
- Cruising/Anchor =80ah/day
- Sea Passage = 129ah/day
However the sea passage use is occasional, and the 450ah house bank would be separated by the engine, so I guess I'll wait for battery technology to improve and settle on 225ah. I am going to add about 280 to 300 watts of solar eventually.
I don't have my Nigel Calder, available now, but will check the attached diagram later. This is the best I can do at this point.
I am wondering now if the combiner is going to confuse the Link10 worse than it already is.

[rgleason]

Discussion about sizing wires for the Battery Cables & Engine Starter one of the the critical maximum loads.