Batteries and a factory (?) mis-wired battery selector switch

[Michael]

NEW INTRODUCTION 17 June 2012 - Unfortunately, the following article now requires a major correction (in addition to the one in the next paragraph), and, if anyone knows a good recipe for removing egg from a face, please send it along. My big assumption in this article, that the location of the terminals on the type of Guest battery selector switch aboard Hali (for which I could not find a diagram) were the same as those in a Perko battery selector switch (for which I did find a diagram), turns out to have been wrong.  In the result, the conclusion I drew that the Guest terminal had been mis-wired was unjustified, and the follow-on conclusions I drew about that mis-wiring causing battery problems were foolish. I would like to delete the article, but it attracted comments that may be helpful to others -- and it may not be entirely useless to see how foolish another C34 owner can be. So the article survives to provide context -- and pain!

[Please mentally correct my following article in light of Maine Sail's later clarifying note that the common post/terminal (on the backside) of the battery selector switch is not the same thing as the Both position (on the front) of the battery selector switch, and that the Both position is not a terminal.  The Guest battery selector switch described in this article has its common post/terminal immediately behind the Both selector position and, in this sense, differs from the diagram for a battery selector that Maine Sail provides.]

Like most boats, Hali is blessed by the presence of angels and cursed by the presence of gremlins.  We have discovered that gremlins often operate in pairs or gangs, so that when you think you have solved a problem, it recurs and you find another gremlin laughing at you.

Since we acquired Hali -- our 1997 C34 Mark II -- in 2007, she has had a battery gremlin.  The diet of this gremlin has consisted of a battery or two every year or two.
  
In case it might help others apparently afflicted with original mis-wiring at the battery selector switch, this is our story of (we hope) finally catching this gremlin.

Hali came to us equipped with:

1.     an automotive starting battery ;
2.    two 4D flooded lead acid batteries as house batteries;
3.    an old battery charger;
4.          a Marinco Guest Off-1-Both-2 battery selector switch (“Guest”); and
5.          an electrical-relay-operated battery isolator/interconnect switch in the charging wire between the engine alternator (via the starter motor) and the Guest.

Over the years, sometimes prodded by discovering dead and dying batteries, we:

6.   replaced the old battery charger with a Xantrex XC3012 battery charger;
7.    added a Link 20 battery monitor;
8.    added a “normally off” 15 pounds per square inch oil pressure switch in the alternator-to-Guest charging circuit, so that the alternator would charge the house batteries (in addition to the starting battery to which it is directly connected) once the engine had started and engine oil pressure had risen to at least 15 psi;
9.    a switch, parallel to 8 and connected to 5, that is usually left off so as not to connect the house batteries to the engine for starting purposes but that can, by setting it to “On”, link the house batteries to the engine if the house batteries are needed to help start the engine.

In making these upgrades, we did not create our own wiring diagram or check the original wiring connections on the Guest. (Stu Jackson would undoubtedly say these omissions were bad mistakes. We would now agree.)

The battery gremlin brought matters to a head this year when, for the second year in a row, he ate Hali’s #1 house battery and began eating #2 house battery.

In previous years, we had guessed that similar problems had been caused by:

(a)    a defective battery charger – hence the purchase of 6 and our first round of new 4D batteries;
(b)   the electrical drain of a relay switch – hence our installation of 7, 8, and 9; and
(c)    a bilge pump that operated more than we realized – hence our installation of a bilge pump cycle counter (which established the bilge pump was not running frequently).   

In retrospect, it is apparent that in those previous years we had been only guessing at the identity of the gremlin and that we had thrown money at imagined fixes instead of getting to the bottom of the problem.

This year, it was time to get serious and trouble-shoot the whole electrical system.

We learned how to use a multimeter.  We made a wiring diagram.

Still, our gremlin took days to come into view.

Along the way, we realized that we did not really understand how the Guest worked.

We never did find a manufacturer’s diagram for the Guest but, based on a diagram for a Perko battery selector switch that is assumed to operate similarly, it appears that the Guest should have been connected up as follows:

•   Guest terminal “1” connects to house battery #1 positive terminal
•   Guest terminal “Both”  is the common terminal to which the “charging circuit” from the engine attaches;
•   Guest terminal “2” connects to house battery #2 positive terminal

But how was our Guest wired up?

A wire properly connected Guest terminal “1” to the positive terminal of house battery #1.  But the wire from the positive terminal of house battery #2 terminated at Guest terminal “Both” instead of at Guest terminal “2”; and the engine charging wire connected to Guest terminal “2” instead of to Guest terminal “Both”.

This mis-wiring, which seems to have been with the boat since she was built, had unfortunate consequences.

When Guest “1” was selected, no charging current from the engine ever reached house battery #1.  (With the battery selector at that setting, we believe normally a connection would be made between the Guest terminal “1” and the Guest common (Both) terminal, with the result that if the switch was correctly wired, a charging voltage would reach house battery #1 by the route: engine alternator to Guest terminal Both to Guest terminal 1 to house battery #1 positive terminal.  But as the charging wire connected to Guest terminal #2, no charging voltage reached house battery #1 when Guest “1” was selected.)

All was well insofar as charging the house batteries from the engine was concerned if the engine was running and Guest “Both” was selected, because then the Guest connected, as it should, all three terminals (1-Both-2) together, and both house batteries #1 and #2 received a charge.

But, if the engine was not running and no shore power was running the 110 volt shore powered battery charger and Guest “Both” was selected and the house battery #1 was run down – a set of circumstances that occurred when anchored-out while cruising -- house battery #2 would try to charge house battery #1, and the gremlin who had attacked house battery #1 would begin destroying house battery #2.

We have speculated why the system was mis-wired in this way.

Our conclusion, which may be completely unfair to someone, is that the factory electrician pulled a short charging wire or cut it short, so that it could reach Guest terminal “2”, which is lower down on the Guest, but not reach Guest common (Both”) terminal, which is higher up.  Faced with the nuisance of pulling a new wire, the electrician (we speculate) chose the expedient work-around of connecting the wires to the "wrong" terminals.  But the wiring was only "wrong" if you didn't know the workaround and selected something other than Guest "Both".

For years, we had noticed that the shortness of all the major wires to the Guest severely limited how far the electrical panel (where the Guest is located) could be opened.  We were simply unaware of the electrician's work-around.  In our early days, we usually did select "Both",  but in recent years, we fed the gremlin by selecting Guest "1" and cut back on our use of shore powered battery charging.

Our solution this year, which wiring codes might not have allowed the Catalina electrician (assuming he was the culprit), has been to add a short pigtail onto the engine charging wire and re-wire the Guest correctly.  Now, the selection made on the Guest means what we had previously, intuitively but incorrectly, thought it meant.  If Guest “1” is selected and the engine is running, house battery #1 is being charged and house battery #2 is not being charged.  If Guest “Both” is selected and the engine is running, both house battery #1 and house battery #2 are being charged.  If Guest “2” is selected and the engine is running, house battery #2 is being charged and house battery #1 is not being charged.

Our conclusion that original mis-wiring is the gremlin responsible for Hali's dying batteries has not yet been proven by the passage of time.

We still fear the appearance of a battery-eating larger-brother gremlin.

[mainesail]

Most of these boats came from the factory with just two 4D's. The starter battery was likely added at the dealer or by a PO?

There is no need to separate "house" batteries with the 1/2/BOTH and in fact it can lead to the issues you found, when you don't have the wires clearly labeled, and can lead to uneven wear and shorter life, especially when folks begin to "alternate" house battery use..  It also makes it impossible to track the "house bank" unless you have a dedicated battery monitor for each of the house batteries.

This to me seems a clear case of improperly labeled wires. The VAST MAJORITY of boats lack any sort of labeling.

Labeled wires help prevent improper connections:


This simple diagram gives you all you want and the redundancy with the switches you have.. Combine the two 4D's with jumpers and make them 1 bank and place on the #1 post. and wire the start battery as shown. This gives you an isolated starting battery BUT it can still be used for 100% redundancy.

[Stu Jackson]

Michael,

Glad to see you back here.

You may be aware of the "Sticky" topics which include the "101 Series" that we developed since you've been here.  You also made the "Critical Upgrades" links for your way-back engine wiring issues!

In addition to Maine Sail's post above, these two topics, from the "Electrical 101" sticky, discuss what he's said in much more detail.

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 [please note the comment on MS's wiring diagram - different end of same wire]

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

Ain't doing wiring diagrams "somewhat" helpful?  

[Michael]

Maine Sail and Stu,

Nice to be back, too, and thank you for your comments, diagrams, and references. I will work my way through them.

With respect to your comment about labelling, MS, how true that most boats, at least ones I have seen, don't have labelled wiring.  That was certainly the case with the wiring aboard Hali until last year when we got a label-maker that attaches to a laptop. Now the problems are to resist labelling everything and, for wiring, to adopt a relatively consistent, succinct, and coherent labelling convention.  Stu's admonitions regarding making a wiring diagram seemed to grow louder and more relevant the longer we put off doing it. Even labelling would have been easier (making shorter labels possible) if a wiring diagram, to which the labels could have made implicit reference, had been made up. MS, it looks like you adopted some sort of succinct labelling convention on the labels shown in your picture above but I can't blow up the picture enough to know what it is. We haven't finished labelling Hali's wiring, nor finished her wiring diagram, so any suggestions you might make would not be wasted on us (although I apologize for not searching the message board for this topic before raising the question).

Regarding your wiring diagram above, MS, it is beautiful.  What tool are you using? Visio?

Also regarding that diagram, I wondered about your depiction of the C post. Isn't the C post (which I take to be what I am calling the common terminal) generally the BOTH terminal? (But I see Stu references an article you have written about the 1-2-Both switch, so I had better read that before asking anything more.)

Again, thank you both.

[mainesail]

Michael,

The "C" post is NOT the BOTH terminal. BOTH is not a terminal it is a combination of #1 & #2. When in BOTH they output to "C".... The "C" post is for all intense and purposes your ON post and your 1/2/BOTH is where ON comes from..

I use MS Paint and it is a PITA...... The labels are TZ labels by Brother and I go over them with clear heat shrink..

Here's a better close up..

[Stu Jackson]

Michael,

There are three posts on the switch: 1, 2 and C

There are four positions on the switch:  off, 1, both, 2

[Michael]

Stu and Maine Sail,

Thank you both for your clarification of the common post issue. [As a result, I have posted a warning at the start of my first post above.]

MS, thank you for the closer-up photo of your wiring labels. The use of clear heatshrinks over the labels is a great idea. I had taken to putting my TZ labels around the wires with the label tails adhering to themselves, in order to make sure the labels remained in place, which they did not always do when run along a wire. A problem with that orientation is that part of the description on the label is illegibly hidden from view behind the wire. Your heatshrink method seems altogether better, ensuring the label remains in place along the wire and entirely visible. As for a labelling convention for wiring, you may have the advantage of labelling only for someone who knows your system or has a wiring diagram, because it appears (although I may have this wrong) that you label each wire with the name of its remote source but not with the name of its local connection. In the absence of a wiring diagram when I started labelling, I adopted  a wordy convention of describing a wire on its label with two names, the first being the name of the wire's local connection and the second being the name of the wire's remote connection. Example: "Battery selector C post <--> Battery interconnect stb term".  But these labels are long winded and need to be printed in small type!

[Michael]

The preceding posts should be corrected as indicated in the new [June 17, 2012] introduction to the first post above.  Also, Stu Jackson and Maine Sail may have puzzled over my assertion that on the Guest battery selector the Common terminal lay behind the Both switch position.  In fact, it doesn't.  It lies (at least on the type of Guest battery selector switch aboard Hali), counter-intuitively, behind the "2" switch position.