Catalina 34

General Activities => Main Message Board => Topic started by: Stu Jackson on October 29, 2010, 05:55:36 PM

Title: Electrical Systems 101
Post by: Stu Jackson on October 29, 2010, 05:55:36 PM
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 ( and his own website: (

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


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

The All-Important Energy Budget:,3976.0.html (,3976.0.html)

IMPORTANT BASICS  What are amps & amp hours  (thanks to StuM from

Record of Daily Energy Use of 100 ah per day:,6353.msg41471.html#msg41471 (,6353.msg41471.html#msg41471)

Largest House Bank 101 (by Nigel Calder),5807.msg45046.html#msg45046 (,5807.msg45046.html#msg45046)

and Maine Sail's excellent writeup: (

Why jump start packs make little sense (isn't turning a switch easier than wiring something together when things are dicey???) (

Wire Sizing Tables from West Marine (unfortunately they removed the handy charts! around 2016) ( ( 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 Fuse & Wire Sizing Tables: (

Alternator/Batteries & "The Basic" 1-2-B Switch BEST Wiring Diagrams,4949.0.html (,4949.0.html)

The Ample Power Primer (

OEM 1-2-B Switch Wiring History,4949.msg30101.html#msg30101 (,4949.msg30101.html#msg30101)

Basic Battery Wiring Diagrams  This is a very good basic primer for boat system wiring:,6604.0.html (,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) (

This is a newer primer for boat system wiring design with a thorough digram:   Building a Good Foundation (October 2016)

The Short Version of the 1-2-B Switch Stuff:,5977.msg38552.html#msg38552 (,5977.msg38552.html#msg38552)  This is a link to the Electrical Systems 101 Topic, reply #2

What are ACRs, Combiners & Echo Chargers?  (by Maine Sail) [scroll to the top] ( and,9404.msg70131.html#msg70131 (,9404.msg70131.html#msg70131)

Making Sense of Automatic Charging Relays  (2019)

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

another good discussion, scroll to the top to start: (

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. (

20 Hour Capacity Test by Maine Sail

Alternator Installation 101 [new Nov. 2018 from Maine Sail] (

Alternator heat, Regulator Controls, Small Engine Mode,4454.0.html (,4454.0.html)

Small Engine Mode - discussion with link to the picture of the toggle switch:,4454.msg27149.html#msg27149 (,4454.msg27149.html#msg27149)

Small Engine Mode - the picture of the toggle switch,4669.0.html (,4669.0.html)

Ammeters & Shunts 101:,6032.0.html (,6032.0.html)

Breaking in New Wet Cell Batteries:,6353.0.html (,6353.0.html)

Understanding Batteries,6488.0.html (,6488.0.html)  with a link to another website

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

Battery Acceptance by Stu,4787.0.html (,4787.0.html)

Why Going Into FLOAT is NOT Full,8216.0.html (,8216.0.html)

10-18-13 LINK BROKEN Battery Acceptance (a very good Maine Sail presentation and further discussions) ( 

10-18-13 LINK BROKEN  Battery Acceptance Observations by Maine Sail (

Overcharging with Combiners or ACRs The MYTH:,7052.0.html (,7052.0.html)

AGM Batteries - Making The Choice (from Maine Sail) (

AGM Battery Issues and the Blue Seas Dual Circuit Switch (from Maine Sail) "DARN AGM Batteries" (

Additional Observations on the Limits of AGMs,5977.msg63004.html#msg63004 (,5977.msg63004.html#msg63004)

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

Alternator Upgrade - a 2018 thread with input from Maine Sail,9773.0.html (,9773.0.html)

Alternator Regulator Wiring Diagrams - all three,4548.0.html (,4548.0.html)

Alternator Regulators - The Differences between ARS-5 and MC-614 Units (scroll UP to see reply #5) (

How Alternators & Regulators Work PLUS External vs. Internal Regulators (by Maine Sail): (

Alternators & Voltage Sensing (by Maine Sail): (

Universal M-25 & M25XP Alternator Bracket Upgrade & Alignment  IMPORTANT,7917.0.html
and,9380.0.html (,9380.0.html)

Golf Cart 6V Battery Wiring,7162.0.html (,7162.0.html)

Stu's Wiring Diagram,4623.msg27335.html#msg27335 (,4623.msg27335.html#msg27335)

Power Share Feature for Link 2000 Controlling Honda Generators
Very helpful hint to control generators and 20A shorepower,1474.0.html (,1474.0.html)

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

Do I Need a Controller for Solar? (

Sizing wiring for solar (

How to Wire a Battery Monitor by Maine Sail: (

New SMART GAUGE Battery Monitor (

Converting a Leece Neville Alternator to External Regulation  by Maine Sail,4879.0.html (,4879.0.html)

Alternator Sources by Maine Sail  (Reply #16),5686.15.html (,5686.15.html)

Wiring a new charger From Maine Sail: (
and (

IMPORTANT Advice on these charger settings:,5977.msg63001.html#msg63001 (,5977.msg63001.html#msg63001)

Echo Charger Use Warning from Maine Sail: (

Installing Battery Selector Switches (the "posts" in the back don't physically match with the switch positions on the front),6911.0.html (,6911.0.html)

removed dates added 7/30/12 :D

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

WalMart Battery Source (

Battery Equalization 101 (

SMART PLUG by Maine Sail (

SMART PLUG Installation Tips by Rick Allen,8460.0.html

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

Programming a Balmar External Voltage Regulator (

Blue Sea Tables (  Scroll down to find the PDF download:  Protect Your Boat with the Correct Size Wire & Fuse Chart.  Handy to keep around.

Battery Fuse Sizing with tables (from Maine Sail) (

Wire Size Calculators 101 ( (

Air Conditioning Electrical 101 by Maine Sail,8710.msg61930.html#msg61930 (,8710.msg61930.html#msg61930)

Seaward Panel History (thanks to Paul Alcock) (

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 (

Raymarine Repairs,7129.msg56425.html#msg56425 (,7129.msg56425.html#msg56425)

Grounding a Honda Generator,6122.msg39290.html#msg39290 (,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 snafued wiring  Reply #8 (
Title: Various System Designs
Post by: Stu Jackson on December 01, 2010, 12:07:50 PM
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,6507.0.html (,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.
Title: Re: Electrical Systems 101
Post by: Stu Jackson on December 06, 2010, 02:31:58 PM
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),5159.0.html (,5159.0.html)

It All Depends on How It's Wired
Title: Re: Electrical Systems 101
Post by: Stu Jackson on December 07, 2010, 09:10:47 AM
One of the most helpful tutorials ever:

Use the Tech tab to download the Ample Power Primer and associated wiring diagrams.
Title: Re: Electrical Systems 101
Post by: Stu Jackson on January 15, 2011, 11:37:11 AM
Wiring & Installing Battery Monitors by Maine Sail (

and an interesting followup discussion - why ONLY voltmeters can't really tell you much about the state of your batteries (
Title: Re: Electrical Systems 101
Post by: Stu Jackson on February 01, 2011, 11:43:07 AM
Another good wiring diagram from Ken Juul, much ike Jim Moe's wiring diagram in the C34 tech wiki



Link to C34 Tech wiki Electrical:
Title: Re: Electrical Systems 101
Post by: Stu Jackson on April 13, 2011, 07:53:05 PM
Updated C34 Tech wiki basic wiring diagram with echo charger:,6225.0.html
Title: Re: Electrical Systems 101
Post by: Stu Jackson on April 16, 2011, 07:34:01 PM

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."

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).
Title: Re: Electrical Systems 101
Post by: Stu Jackson on April 18, 2011, 05:10:56 PM
Important Considerations for AGM Battery Use  (by Maine Sail)
Title: Re: Electrical Systems 101
Post by: Dave Spencer on April 18, 2011, 07:01:40 PM
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? 

Title: Re: Electrical Systems 101
Post by: Stu Jackson on April 18, 2011, 08:42:09 PM
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),4669.0.html
Title: Re: Electrical Systems 101
Post by: Dave Spencer on April 19, 2011, 05:43:09 PM
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.

Title: Re: Electrical Systems 101
Post by: Stu Jackson on April 19, 2011, 06:42:48 PM
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.
Title: Re: Electrical Systems 101
Post by: Stu Jackson on May 21, 2011, 06:58:59 AM
For everyone installing a battery monitor:  The "Gotcha Algorithm" thread, a "MUST READ",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)
Title: Re: Electrical Systems 101
Post by: Stu Jackson on June 06, 2011, 08:05:03 PM
Engine Start Problems, with a good discussion of various issues.,5159.0.html     
Title: Re: Electrical Systems 101
Post by: scotty on June 06, 2011, 10:57:31 PM
OK Stu, I'm really impressed by this...I think.  That is to say, it is WAY over my head.  I think I'll study it for a long while.  The only sugestion I have is that you post this on the Tech Wiki site so that it is easly found by future participants in this community.  Once again, good job.
Title: Re: Electrical Systems 101
Post by: Stu Jackson on June 06, 2011, 11:46:24 PM
Scotty, I added it to the electrical section in the Tech wiki, linked right back here, since if I add anything, I'll do it here and the wiki link will "still be alive."  I'm still cludgy on the wiki, this format is much easier for us simple typists and linksters.   :D
Title: Re: Electrical Systems 101
Post by: Stu Jackson on June 11, 2011, 06:22:17 PM
Another good discussion about the 1-2-B switch, from Sailnet, with Maine Sail and Brian from Victoria, BC contributing.  You'll have to wade through answers to the orignal question to get into the heart of the switching discussion.

It gets into, yet again, the "illogical-for-the-intended-use" Blue Seas dual circuit system.  For those of you who have the DC switch, take heed of Maine Sail's advice:  if you like what you have, and understand how it works, and its limitations, then you're just fine.  Simply understand that there are different, and I believe, better ways to set up a boat electrical system.
Title: Re: Electrical Systems 101
Post by: Stu Jackson on June 23, 2011, 06:14:42 PM
One of my "favorite" engine wiring issues:  from page 4 onward:,3347.45.html

[Added to Critical Upgrades page, too.]
Title: Re: Electrical Systems 101
Post by: Stu Jackson on July 08, 2011, 03:52:53 PM
The important ENERGY BUDGET:,3976.0.html

Also discussed in "Breaking In New Wet Cell Batteries," here:,6353.msg41471.html#msg41471
Title: Re: Electrical Systems 101
Post by: Stu Jackson on September 12, 2011, 08:25:20 AM

and for Link products:
Title: Re: Electrical Systems 101
Post by: Stu Jackson on September 13, 2011, 02:01:22 PM
AGM Battery Failure and a good discussion of the Blue Seas Dual Circuit design concept in a real life situation.

Thanks again to Maine Sail.

Darn AGMs
Title: Re: Electrical Systems 101
Post by: Ron Hill on September 13, 2011, 02:45:48 PM
Stu : I'm glad that you posted Mainsails thoughts on AGM batteries.

I've never heard of equalizing an AGM and don't ever plan on doing that!
On the 1 2 B switch, mine is even simpler - it's ON or OFF manually operated by the Captain.
As far keeping AGMs fully charged after discharge is not that difficult. It's harder at anchor, but that's what the Honda (or solar panels) are for.
Now with LEDs the only big battery drain left is the fridge - unless you have self inflected wounds from something like a 110V hair dryer or coffee peculator etc.  
After opening up the boat, we always try to stay at the dock over night (plugged in) to get the fridge cooled down. Then taking off the next morn the fridge is stabilized. We also have dock mates that when called will plug in and turn on the fridge to give it a head start before we arrive.
I've been doing overnights for over 24 years and from 16:00 to 08:00 the next day we typically only use about 30 amp hours.  By the time I start the engine and pull anchor the alternator has put 3/4 of the amp deficit back into the batteries.  Motor for another 30 minutes and they are almost fully charged.

Interesting article.  
Title: Re: Electrical Systems 101
Post by: Stu Jackson on September 16, 2011, 06:07:53 PM

A sometimes humorous discussion of how to do it, an offshoot of the excellent battery charger evaluation topic by John Nixon:,4338.0.html (,4338.0.html)
Title: Re: Electrical Systems 101
Post by: Stu Jackson on October 12, 2011, 09:58:49 AM

Thanks again to Maine Sail (
Title: Re: Electrical Systems 101
Post by: Stu Jackson on September 06, 2013, 04:07:21 PM
Golf Cart Batteries compared to 4D & 8D 12V Batteries: (

See Reply #5, by Maine Sail.  A definitive explanation of how to save your back and increase your investment in lead.   :clap
Title: Re: Electrical Systems 101
Post by: Ron Hill on September 07, 2013, 12:51:21 PM
Guys : For those of you that don't know what a 4D or 8D battery looks like, then next time you're in a battery shop or West Marine look and lift a 4D battery!! 

That will surely convince you!!  Then picture carrying it up the companion way steps.
Title: Re: Electrical Systems 101
Post by: Stu Jackson on January 22, 2016, 11:06:58 AM
Maine Sail's new topic on why using battery voltage as an indicator of battery SOC is nonsense.

His conclusion:

If you expect or plan to use voltage as your indicator of SOC and when to re-charge I would strongly urge you to begin recharging at a bare minimum of 12.1V, even when drawing your average house loads. Remember your house loads are a lower average load than the 20 hour rate so you will be better served to begin re-charging at 12.15V -12.2V in order to get the most life from your bank.

Here's the full topic: (
Title: Re: Electrical Systems 101
Post by: mainesail on January 22, 2016, 11:51:31 AM
Maine Sail's new topic on why using battery voltage as an indicator of battery SOC is nonsense.

Please be aware that Stu's "nonsense" interpretation of what I wrote is his interpretation.

Voltage can be used but just like all the folks who use Coulomb counters incorrectly, so do those who often use voltage. Using voltage is not at all nonsense but to do it correctly or remotely accurately takes an owner who has an active role in understanding his or her battery bank beyond just slapping a generic voltage to SOC chart on the bulkhead near the volt meter. Is using voltage to try and predict SOC nonsense, not at all, but most folks do have a tough time with it, as they do with Coulomb counters..
Title: Re: Electrical Systems 101
Post by: Stu Jackson on February 04, 2016, 12:17:29 PM
Re: Sterling Procharge Ultra Battery Charger Problems

OP: We bought a new Sterling Procharge Ultra battery charger, installed it and set it according to the instructions. For the first few months it seemed to charge okay and then it stopped. The charger was on but it didn't charge voltage and the indicator showed 00. The only way to get it working again was to turn it off and on again.

After going through this a couple of times (each time it was after a month or two of what seemed to be normal charging), I contacted Sterling (the company) and the battery charger was replaced under warranty.

Now the replacement battery charger is going through exactly the same behaviour. It stops charging. Charger is on but doesn't charge voltage and indicator shows 00. I "reset" the battery charger by turning it off and on and then it goes back to working again.

Does anybody have any ideas as to what the problem is?

Maine Sail's answer

Sounds like some of you may have received a California Emissions Compliant charger or CEC compliant unit. Best thing to do is to turn that feature off. You want to run it in PS mode not BC mode.....

When you first boot the newer CEC compliant chargers (ProMariner ProNautic P and Sterling ProCharge Ultra) you will see 888 on the screen followed by "bc" for about 5-7 seconds.

While "bc" is still on the screen hit the up or down arrow until it says "ps" then hit enter. The charger is now running as a standard battery charger and no longer beholden to the laws of the State of California which force the charger to turn off the display and go to sleep....
Title: Re: Electrical Systems 101
Post by: Stu Jackson on February 04, 2016, 01:18:09 PM
Additional Observations on AGM Batteries  (from --- (

Topic:  Battery advice, please?

Summary:  This supports much of what Maine Sail has written about the choices we have to make about battery types.

Copy of text from CF for those of you who don't like clicking on links:

I have an AGM bank and I recommend against them for cruising.

I have AGM due to sizing constraints of the battery box, but they require being fully recharged at a min of a couple of times a week. And if yours allow it, equalizing monthly.
Great batteries for what I do now which is weekend cruise and a vacation once in awhile, but the rest of the time tied to a dock with shore power.

My opinion is if you have AGM, you need significant Solar, and my plan is to run the genny a couple times a week early in the morning to get through bulk phase and deep into absorption with the idea that when there is enough Sun, Solar can top them off.

Even in the tropics, even with unlimited Solar, due to acceptance rate, you can't get to 100% charge on Solar alone, just not enough time.

With no Solar, a couple of times a week the generator needs to run all day.

I believe 10 years is pretty uncommon for a bank, even if you do everything right, I believe 5 is closer to average.

With out going with significant Solar, and a big ole charger, it may make more sense to do what you have to to put in golf cart batteries with the idea of replacing them every few years as you'll likely be cycling them between 50% and 85%.

AGM are high $ batteries and will not last if you cycle them at partial charge more than a year or two.