Small Boat Electrical for Sail

[Bleemus]

Originally Posted by 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).

Shouldn't there be a gap of some sort between batteries? Those seem like they would get too hot too fast and limit charging efficiency.

[rgleason]

I agree, but I don't know how big.a gap.

[john61ct]

Between 5/16" and 9/16"

[rgleason]

This wiring diagram has been revised to:
1. Incorporate as many of the small fuses as possible in a positive Battery Fuse Panel.
2. To increase main switch, starter and battery cables to 1/0 to reduce voltage drops, as per the BlueSea Circuit Wizard, and MainSail's suggestions regarding the voltage-drop effect of additional connections and fuses.
3. To simplify the large fuses as much as possible.

This schematic will require complete rewiring of the system, and will add a number of connections and safety fuses between critical points. Note that the starter currently starts the engine instantly with an AWG 1 Cable directly wired with no fuses (so in some respects this additional work and cost seems completely unnecssary).

As you can tell, I am not in favor of spending boat money and time needlessly, but this seems to be the bare minimum standard for small boats. I would appreciate some experienced eyes reviewing this wiring diagram for opportunities to change anything that is over-specified or over-designed (or under specified).


PS: I notice that the two 250a fuses should be changed to 225a.

[Bleemus]

Originally Posted by john61ct

Between 5/16" and 9/16"

Thanks John. Actually smaller than I expected but sounds reasonable.

[rgleason]

Space between Bank batteries: Between 5/16" and 9/16"

Would this space be expected between the battery case and the batteries as well?
Is there a way to improve air flow to reduce battery temperature?

[john61ct]

A small fan, but not needed.

And I was just funnin' with the excessive precision, the point is just to have a little aitflow between.

Also rarely needed AFAIK, few setups will actually heat up the batts much over ambient anyway.

[rgleason]

Glad this happened before I rewired!!

MRBF Terminal Fuse - 225A 5188 Discontinued.
ANL Fuse - 225 Amp 5130 Discontinued


Now the choices left are use 200a with 1/0 or continue to use the existing AWG 1.
Or to move up to a 250a and use 2/0, darn

[Stu Jackson]

Originally Posted by rgleason

Glad this happened before I rewired!!

MRBF Terminal Fuse - 225A 5188 Discontinued.
ANL Fuse - 225 Amp 5130 Discontinued


Now the choices left are use 200a with 1/0 or continue to use the existing AWG 1.
Or to move up to a 250a and use 2/0, darn

rg,


Here's the part I'm unclear on. You say rewire. Do you mean actually physically. Did you install wiring based on an earlier diagram and now have to redo it? Or is this still all on paper?


If your #1 wire works to start the engine, why would you even consider going to 2/0?


Often, as I mentioned earlier, wiring sizes have a range of amperage they can handle. Unless that "existing" wire is way out of spec for the load and distance, if it works...???


Help me understand existing in your case.

[rgleason]

Stu, the existing diagram is earlier in this thread. Over 27 years of ownership we have upgraded the wiring, with the lastest inprovements in 2015 when we replaced the engine with yanmar 3ym30. Now the main cables are AWG 1 and some neg cables are yellow.

With 225a fuses being discontinued, there is little incentive to change the cables unless adding fuses and more connections is going to create an unacceptable voltage drop.

I think the next thing to do is use Mainesail's measurements and actually calculate the expected voltage drop for the critical circuits.

PS: I had been intending to rewire with 1/0 and 225a fuses, but with 225a fuses discontinued there may be no reason to change. I will just have to try 200a fuses with my existing AWG 1 cable

[rgleason]

Also the suggestion to turn on loads and measure voltages and current is a good one and might show where any problems might be.
BTW the alternator is still a short 8" #4 red to the starter + and a new 2015 #1 red from there to the C on 1both2.

[rgleason]

Very useful Links used and created getting to this point.

http://www.cruisersforum.com/forums/...d.php?t=204316

http://www.cruisersforum.com/forums/...d.php?t=204604

http://www.cruisersforum.com/forums/...d.php?t=204951

http://www.cruisersforum.com/forums/...d.php?t=204890

http://www.cruisersforum.com/forums/...d.php?t=204101

Regarding use of ZapStop on Alternator
Still effective with external regulation and Alternator output AO direct to house batt.
http://www.cruisersforum.com/forums/...d.php?p=356047

http://www.cruisersforum.com/forums/....php?p=2664832

http://www.cruisersforum.com/forums/...d.php?t=203612

Stu's Electrical Systems 101 and use of 1both2 switch. Excellent links.
http://c34.org/bbs/index.php/topic,5977.0.html

MaineSail's Excellent Marine How To
https://marinehowto.com/

GC2 Flooded Deep Cycle Battery Charging and State of Charge (SOC)

http://www.cruisersforum.com/forums/...d.php?t=201841

http://www.cruisersforum.com/forums/...d.php?t=203541

http://www.cruisersforum.com/forums/...d.php?t=203925

http://www.cruisersforum.com/forums/...d.php?t=204753

SOLAR PV

http://www.cruisersforum.com/forums/...d.php?t=204349

http://www.cruisersforum.com/forums/...d.php?t=203803

[rgleason]

Waeshael has advised that the Charger and Solar which are on a 24hr direct to battery panel, will each need a disconnect switch so that these power sources can be controlled when working on the boat, by shutting off the panel, the charger and the solar,

Additionally when the more powerful and quicker eng-alternator is charging, the slower solar PV should be turned off, to allow the alt to work properly,for example.

See this link
http://www.cruisersforum.com/forums/...d.php?t=204604

[rgleason]

I have also been thinking carefully about how I am going to protect the new connections, busbars and electrical gear, from incoming seawater from the port cockpit locker opening cover for example. It it unrealistic to assume that there will not be several occassions when the stern gets totally pooped and seawater ingresses into the port locker drenching the batteries and all the wiring.

A friend had that happen on a recent crossing. He had to replace several expensive pieces of gear.

So I've decided to build a simple 1/4" plexi cover that fits over the entire installation, that must be removed to change fuses or work on the electrical. It will allow air flow but be fitted up under the closed part of the port seat to prevent water reaching the electrical wiring, etc.

If the port locker gets filled with water, this panel will not help, but that would be a more dire situation. Key thing is to keep these lockers closed with snaps on the locks so the seat hatch does not open when knocked down. Also adding some foam gaskets around the seat lid would help.

If the batteries get drenched somehow there is not much I can do. The battery case may partly fill with water, but provided they are secure, what can happen, provided I have a good sized drain hole in the battery case a couple of inches below the top of the case?

[rgleason]

I am planning on installing the charger in a similar location on the starboard cockpit locker bulkhead. I am concerned about protecting this equipment from water ingress too, while providing adequate air flow when in operation in a harbor.
Perhaps a similar plexi-panel that is removed when using shore power to charge the batteries will help, along with lifting the starboard lid up for adequate air flow.