Electrical Systems 101

[Stu Jackson]

Over the past decade or more, "regular" electrical topics come up repeatedly.  In developing responses to questions, many of us use the handy links to earlier discussions.  I've developed this "Electrical 101" topic, which is a group of links to popular subjects and those discussions.   Many of them include links to other websites and message boards, since boat electrical systems are not boat-specific.  Many thanks to Maine Sail, not only for his contributions to this message board, but for his "Musings with Maine Sail" on www.catalinaowners.com

https://forums.sailboatowners.com/forums/musings-with-maine-sail.135/ and his own website:  https://marinehowto.com/

You could buy a few good books (see Reply #7 below), or you could read this stuff. Good luck.

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Here are some good "intro" courses for Electrical Systems:

The All-Important Energy Budget:

http://c34.org/bbs/index.php/topic,3976.0.html

IMPORTANT BASICS  What are amps & amp hours  (thanks to StuM from CF.com)

http://www.cruisersforum.com/forums/f14/amps-v-amp-hours-v-amps-hr-154363.html#post1933764

Record of Daily Energy Use of 100 ah per day:

http://c34.org/bbs/index.php/topic,6353.msg41471.html#msg41471

Largest House Bank 101 (by Nigel Calder)

http://c34.org/bbs/index.php/topic,5807.msg45046.html#msg45046

and Maine Sail's excellent writeup:  https://forums.sailboatowners.com/index.php?threads/multiple-house-banks-vs-one-house-bank.184137/&highlight=windlass

NEW March 2022   LifePO4 Batteries on Boats (Maine Sail)
https://marinehowto.com/lifepo4-batteries-on-boats/

NEW July 2024   LifePO4 Batteries "Easy" Installation  (Maine Sail)
https://marinehowto.com/easy-lifepo4-conversion/

Why jump start packs make little sense (isn't turning a switch easier than wiring something together when things are dicey???)
https://forums.sailboatowners.com/index.php?threads/battery-modifications.193743/#post-1489220

Reverse Polarity 101 from BlueSea:  https://www.bluesea.com/support/articles/AC_Circuits/90/Reverse_Polarity_Indicators

Wire Sizing Tables from West Marine (unfortunately they removed the handy charts! around 2016)   http://www.westmarine.com/WestAdvisor/Marine-Wire-Size-And-Ampacity   www.bluesea.com also has good material on this and fusing, but it's a PDF download and doesn't link.  Here's the link to the page, scroll down for the PDF download of the Protect Your Boat With The Correct Size Wire And Fuse - Wire Size Chart:  https://www.bluesea.com/support/reference  which links to this table:
https://d2pyqm2yd3fw2i.cloudfront.net/files/resources/reference/20010.pdf

Battery Fuse Sizing from Maine Sail
https://forums.sailboatowners.com/threads/battery-fuse-sizing-how.130775/

Alternator/Batteries & "The Basic" 1-2-B Switch BEST Wiring Diagrams

http://c34.org/bbs/index.php/topic,4949.0.html

The Ample Power Primer  http://www.amplepower.com/primer/primer.pdf
Sorry, link is gone, Ample Power unfortunately closed.  They were so ahead of their time!  [May 2019]
The Ample Power Primer is still available on the Wayback Machine at https://web.archive.org/web/20160323132827/http://amplepower.com/primer/primer.pdf
It remains one of the best...
Many thanks to Bill Murdoch

OEM 1-2-B Switch Wiring History  http://c34.org/bbs/index.php/topic,4949.msg30101.html#msg30101

1-2-B Considerations (New 2020 - Rod finally got around to diagramming what I had done in the above link in 2009 :) )
https://marinehowto.com/1-2-both-battery-switch-considerations/

Basic Battery Wiring Diagrams  This is a very good basic primer for boat system wiring: http://c34.org/bbs/index.php/topic,6604.0.html

This is another very good basic primer for boat system wiring:   The 1-2-B Switch by Maine Sail (brings together a lot of what this subject is all about)
http://forums.catalina.sailboatowners.com/showthread.php?t=137615

This is a newer primer for boat system wiring design with a thorough diagram:   Building a Good Foundation (October 2016)
http://forums.sailboatowners.com/index.php?threads/building-the-dc-electrical-foundation.181929/#post-1332240

The Short Version of the 1-2-B Switch Stuff:  http://c34.org/bbs/index.php/topic,5977.msg38552.html#msg38552  This is a link to the Electrical Systems 101 Topic, reply #2

How to properly wire & switch a DCP switch - Maine Sail's "workaround" explained Replies #28 & 29
https://forums.sailboatowners.com/threads/what-size-fuse-for-automatic-charging-relay.1249932137/page-2

Maine Sail's DCP Wiring Diagram
https://forums.sailboatowners.com/threads/operating-the-house-start-battery-selector.1249933496/#post-1745066

AGM Battery Issues and the Blue Seas Dual Circuit Switch (from Maine Sail) "DARN AGM Batteries"
https://forums.sailboatowners.com/index.php?threads/darn-agm-batteries.133773/


What are ACRs, Combiners & Echo Chargers?  (by Maine Sail) [scroll to the top]
http://forums.catalina.sailboatowners.com/showthread.php?p=742417 and http://c34.org/bbs/index.php/topic,9404.msg70131.html#msg70131

Making Sense of Automatic Charging Relays  (2019)
https://marinehowto.com/automatic-charging-relays/

Basic Battery System Descriptions (bottom of page one, then to page two)

http://forums.catalina.sailboatowners.com/showthread.php?t=104505

another good discussion, scroll to the top to start:  http://forums.catalina.sailboatowners.com/showthread.php?p=680363&highlight=duo%20charge

Loaded Battery Voltage vs. SOC - AGM Lead Acid Battery  by Maine Sail --- why using battery voltage as an indicator of battery SOC is something that requires thought & understanding.

http://forums.sailboatowners.com/index.php?threads/loaded-battery-voltage-vs-soc-agm-lead-acid-battery.176854/

20 Hour Capacity Test by Maine Sail

http://forums.sailboatowners.com/index.php?threads/battery-replacement-agm.179118/#post-1295253

Alternator Installation 101 [new Nov. 2018 from Maine Sail]
https://marinehowto.com/marine-alternator-installation-tips-tricks/

Alternator heat, Regulator Controls, Small Engine Mode

http://c34.org/bbs/index.php/topic,4454.0.html

Small Engine Mode - discussion with link to the picture of the toggle switch: http://c34.org/bbs/index.php/topic,4454.msg27149.html#msg27149

Small Engine Mode - the picture of the toggle switch http://c34.org/bbs/index.php/topic,4669.0.html

Alternator Repair Shops  https://c34.org/bbs/index.php/topic,7917.msg55085.html#msg55085

Using a 3/8" Belt on a Larger Alternator 
https://c34.org/bbs/index.php/topic,10702.msg83288.html#msg83288

Programming a Balmar Voltage Regulator: (Thanks to Maine Sail)
https://marinehowto.com/programming-a-balmar-voltage-regulator/

Ammeters & Shunts 101: http://c34.org/bbs/index.php/topic,6032.0.html

Breaking in New Wet Cell Batteries:  http://c34.org/bbs/index.php/topic,6353.0.html

Understanding Batteries http://c34.org/bbs/index.php/topic,6488.0.html  with a link to another website

What is a Deep Cycle Battery? (from Maine Sail's website)

http://www.pbase.com/mainecruising/deep_cycle_battery

Battery Acceptance by Stu  http://c34.org/bbs/index.php/topic,4787.0.html

Why Going Into FLOAT is NOT Full

http://c34.org/bbs/index.php/topic,8216.0.html

10-18-13 LINK BROKEN Battery Acceptance (a very good Maine Sail presentation and further discussions)   http://forums.catalina.sailboatowners.com/showthread.php?t=114054 

10-18-13 LINK BROKEN  Battery Acceptance Observations by Maine Sail
http://forums.catalina.sailboatowners.com/showthread.php?p=674108&highlight=battery%20acceptance

Overcharging with Combiners or ACRs The MYTH:
http://c34.org/bbs/index.php/topic,7052.0.html

AGM Batteries - Making The Choice (from Maine Sail)

https://forums.sailboatowners.com/index.php?threads/agm-batteries-making-the-choice.124973/

AGM Battery Issues and the Blue Seas Dual Circuit Switch (from Maine Sail) "DARN AGM Batteries"
https://forums.sailboatowners.com/index.php?threads/darn-agm-batteries.133773/

Additional Observations on the Limits of AGMs  http://c34.org/bbs/index.php/topic,5977.msg63004.html#msg63004

Automotive Alternators vs. Deep Cycle Battery banks  (by Maine Sail) (NEW  March 2016)

http://www.pbase.com/mainecruising/automotive_alternators_vs_deep_cycle_batteries

Alternator Upgrade - a 2018 thread with input from Maine Sail
http://c34.org/bbs/index.php/topic,9773.0.html

Alternator Regulator Wiring Diagrams - all three http://c34.org/bbs/index.php/topic,4548.0.html AND a superb post showing the BACKS of OEM alternators from Ken Kloeber, see reply #7 here: https://c34.org/bbs/index.php/topic,12025.0.html

Alternator Regulators - The Differences between ARS-5 and MC-614 Units (scroll UP to see reply #5)
http://forums.catalina.sailboatowners.com/showthread.php?p=1103132

How Alternators & Regulators Work PLUS External vs. Internal Regulators (by Maine Sail):  http://forums.sbo.sailboatowners.com/showthread.php?t=125392

Alternators & Voltage Sensing (by Maine Sail):http://www.pbase.com/mainecruising/regulator_voltage_sensing

Universal M-25 & M25XP Alternator Bracket Upgrade & Alignment  IMPORTANT

http://c34.org/bbs/index.php/topic,7917.0.html

and
http://c34.org/bbs/index.php/topic,9380.0.html

Golf Cart 6V Battery Wiring  http://c34.org/bbs/index.php/topic,7162.0.html

Stu's Wiring Diagram  http://c34.org/bbs/index.php/topic,4623.msg27335.html#msg27335

Power Share Feature for Link 2000 Controlling Honda Generators
Very helpful hint to control generators and 20A shorepower
http://c34.org/bbs/index.php/topic,1474.0.html

Solar Systems:  Selection, Installation & Controllers by Maine Sail  SUPERB

http://www.pbase.com/mainecruising/solar_panel

Do I Need a Controller for Solar?

http://forums.catalina.sailboatowners.com/showthread.php?t=144557

Sizing wiring for solar   http://www.freesunpower.com/wire_calc.php

How to Wire a Battery Monitor by Maine Sail:  http://forums.catalina.sailboatowners.com/showthread.php?t=125606

New SMART GAUGE Battery Monitor  http://www.pbase.com/mainecruising/smart_gauge

Converting a Leece Neville Alternator to External Regulation  by Maine Sail
http://c34.org/bbs/index.php/topic,4879.0.html

Alternator Sources by Maine Sail  (Reply #16)
http://c34.org/bbs/index.php/topic,5686.15.html

Alternator Source from Leo310  Total Parts Canada
https://www.totalpartscanada.com/alternators/#/filter:categories_hierarchy:Alternators$253EMarine$253EUniversal$2520Fit

Wiring a new charger From Maine Sail:

http://forums.sailboatowners.com/index.php?threads/marine-battery-chargers-installation-tips-considerations.136765/#post-880275
and 
https://marinehowto.com/installing-a-marine-battery-charger/

IMPORTANT Advice on these charger settings:  http://c34.org/bbs/index.php/topic,5977.msg63001.html#msg63001

Echo Charger Use Warning from Maine Sail:  http://www.sailnet.com/forums/electrical-systems/72295-xantrex-echo-charger-rant.html

Installing Battery Selector Switches (the "posts" in the back don't physically match with the switch positions on the front)  http://c34.org/bbs/index.php/topic,6911.0.html

removed dates added 7/30/12

Engine Starting Loads - Amp Draw Data (by Maine Sail)
LINK 404 don't use
http://forums.catalina.sailboatowners.com/showthread.php?t=102027

Battery Fuse Sizing - from Maine Sail
https://forums.sailboatowners.com/threads/battery-fuse-sizing-how.130775/
WalMart Battery Source

http://forums.catalina.sailboatowners.com/showthread.php?t=136852

Battery Equalization 101

http://forums.catalina.sailboatowners.com/showthread.php?t=148505

SMART PLUG by Maine Sail

http://forums.catalina.sailboatowners.com/showthread.php?t=159096&highlight=smart+plug

SMART PLUG Installation Tips by Rick Allen

http://c34.org/bbs/index.php/topic,8460.0.html

Differences between Balmar MC-614 and ARS-5 Regulators 101

http://forums.catalina.sailboatowners.com/showthread.php?t=160744&#post1102540
http://forums.catalina.sailboatowners.com/showthread.php?p=1053410&highlight=ars-5

Programming a Balmar External Voltage Regulator
https://marinehowto.com/programming-a-balmar-voltage-regulator/

Blue Sea Tables  https://www.bluesea.com/support/reference  Scroll down to find the PDF download:  Protect Your Boat with the Correct Size Wire & Fuse Chart.  Handy to keep around.


Wire Size Calculators 101 

http://www.genuinedealz.com/voltage-drop-calculator

http://www.bulkwire.com/wireresistance.asp

Air Conditioning Electrical 101 by Maine Sail

http://c34.org/bbs/index.php/topic,8710.msg61930.html#msg61930

Seaward Panel History (thanks to Paul Alcock)

http://www.whalepumps.com/marine/siteFiles/resources/docs/Seaward/manuals/ElectricalPanels.pdf

Bypass The Orange/Red Circuit  - Maine Sail's version of the wiring harness crap, but includes a good discussion of the wires at the back of the old OEM alternators
http://www.pbase.com/mainecruising/universal_wiring_harness_upgrade

Raymarine Repairs

http://c34.org/bbs/index.php/topic,7129.msg56425.html#msg56425

Grounding a Honda Generator

http://c34.org/bbs/index.php/topic,6122.msg39290.html#msg39290

Beneteau Wiring Diagrams - Maine Sail's corrections - Just in case you have a friend with a Beneteau and want to help him with his unusual switching  Reply #8

https://forums.sailboatowners.com/index.php?threads/one-black-and-two-red-electrical-switches.191463/#post-1456512

[Stu Jackson]

Here's the Short Version:

1. Take the alternator output off of the starter and run a new heavy gauge wire to the house bank positive - with a fuse near the battery bank.  Remove the small #10 or #12 wire between the alternator and the starter.

2. Take the shorepower charger's output off the start battery and leave it only on the house battery positive - again fused near the battery. If you have solar panels or a wind gen the output also goes direct to the house bank.

3. Buy either an Echo Charge or an ACR (automatic charge relay) and wire it to the house +, start + and ground. For a single start battery I prefer the Echo Charge. It passes up to 15 amps to the start (aux) battery when a charge current is sensed and stops when the charge current is no longer present. At no time does it parallel the batteries.  [See the Echo Charge Warning in the post right above this one.]

What this does is change your 1/2/both switch to a "use" switch and not a charge switch. It still lets you decide which battery to use for any load but the charging is automatic.

The easiest way to use this system is to use the house bank for everything and keep the auxiliary battery for emergency use. When you arrive on the boat turn the switch to 1 (house I assume) and turn it to off when you leave. Engine starting is easily accomplished by the house bank.

And there is no chance of error.

Added 7/8/11:  And if your echo charger or ACR breaks, then simply use the B position on the switch but ONLY when charging sources are present! !  Backup, backup, backup. Stu

Hawk's Electrical System  http://c34.org/bbs/index.php/topic,6507.0.html  A very interesting discussion of how Tom's system evolved from input from this topic and how he runs his boat - he decided to use his 1-2-B switch instead of an echo charger and has moved his AO to the house bank.  A very nice compromise that works.

The "concept" of using BOTH (except when charging) and to COMBINE a bad bank with a good one is just plain WRONG.  Please, don't do it.

[Stu Jackson]

And another that sometimes links back to the earlier posts:

Engine Starting Issues - that pesky negative ground connection on the engine and that also pesky hidden starter fuse from the start button (look under your alternator)  

http://c34.org/bbs/index.php/topic,5159.0.html

It All Depends on How It's Wired

[Stu Jackson]

One of the most helpful tutorials ever:

The Ample Power Primer is still available on the Wayback Machine at https://web.archive.org/web/20160323132827/http://amplepower.com/primer/primer.pdf
It remains one of the best...
Many thanks to Bill Murdoch

[Stu Jackson]

Wiring & Installing Battery Monitors by Maine Sail

http://forums.catalina.sailboatowners.com/showthread.php?t=125606

and an interesting followup discussion - why ONLY voltmeters can't really tell you much about the state of your batteries

http://forums.catalina.sailboatowners.com/showthread.php?t=132776&page=2

[Stu Jackson]

Another good wiring diagram from Ken Juul, much ike Jim Moe's wiring diagram in the C34 tech wiki

Ken's:
http://www.c34.org/wiki/index.php?title=Wiring_Diagram_with_4_6v_golf_cart_batteries_and_starting_battery_on_Luna_Loca

Jim's:
http://www.c34.org/wiki/index.php?title=Catalina_34_Electrical_System_Upgrade

Link to C34 Tech wiki Electrical:
http://www.c34.org/wiki/index.php?title=Electrical

[Stu Jackson]

Updated C34 Tech wiki basic wiring diagram with echo charger:

http://c34.org/bbs/index.php/topic,6225.0.html

[Stu Jackson]

BOOKS

Every so often folks ask: "What book should I buy to learn electrical stuff about my boat?"

The appropriate answer is: "Depends on how you like to learn."

Go to a chandlery and read a few in person, and start by buying one that you think suits your "level" and is "readable" to you."

Here's a good start:  https://www.bluesea.com/support/reference/536/Recommended_Books_on_Marine_Electrical_Systems

Jan. 2018 - West Marine revised their website, so the following link no longer works.  Darn!  But a Google or Amazon search for "boat electrical books" will do it for you.  Charlie Wing's comes highly recommended by many.

A good starting list is provided by West Marine in the their online Advisors (and usually in their catalogs, one of which should be in your house and the other on your boat).

http://www.westmarine.com/webapp/wcs/stores/servlet/WestAdvisorView?langId=-1&storeId=11151&catalogId=10001&page=Recommended-Books-on-Marine-Electrical-Systems

[Stu Jackson]

Important Considerations for AGM Battery Use  (by Maine Sail)

http://forums.catalina.sailboatowners.com/showthread.php?t=104505

[Dave Spencer]

Wow!  What a great post by Maine Sail.  Great observations on acceptance rates depending on which battery is first in the charging chain.

On a slightly different but similar note, Nigel Calder had a good article in this month's (May) Sail magazine on the perils of some of the new high acceptance rate batteries like TPPL (Thin Plate Pure Lead) and Lithium Ion batteries.  I haven't used these (or even researched them) but it looks like great new technology that will greatly reduce charging times for sailor's battery banks.  However, because the batteries can accept such a high charge rate, the alternator is at or near its maximum capacity for a relatively long period resulting in overheating.  Nigel has offered some ideas on how to deal with these high acceptance rate batteries.

Do we have any thoughts or experience on TPPL or Lithium Ion batteries? 

[Stu Jackson]

Dave, not with the new battery technology, but surely with reducing alternator load and heat:

Small Engine Mode (read the link to the hot alternator topic, too)

http://c34.org/bbs/index.php/topic,4669.0.html

[Dave Spencer]

Thanks for the great links Stu. 
I thought that someday I would surely have a question that this group can't answer. Now, I'm not so certain.

[Stu Jackson]

Dave, you'll find this is as applicable to AGM batteries as it is to the newer technology.  AGMs have high acceptance rates that can tax even high output alternators.

[Stu Jackson]

For everyone installing a battery monitor:  The "Gotcha Algorithm" thread, a "MUST READ"

http://c34.org/bbs/index.php/topic,4922.0.html

DEFAULTS are factory settings that are made to be modified to suit your setup.

Also read this one:

Programming a Battery Monitor (by Maine Sail)

https://marinehowto.com/programming-a-battery-monitor/

[Stu Jackson]

Engine Start Problems, with a good discussion of various issues.

http://c34.org/bbs/index.php/topic,5159.0.html