engine battery switch

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nelson
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Posts: 89
engine battery switch

I have a question about the purpose of the "engine" on/off switch next to the battery switch on my Mk II 36.

{before embarking on this discussion, I realize that many users think that there are better ways to wire these boats than the good old 1-2-off switches.  I respect your views, but I'm pretty good with the current system.  After 25 years of the 1-2-off two-bank system on 3 Catalinas and a Newport 30, I've never had a problem. Hence, I'm sticking with what works for me.}

The Mk II Catalina 36 has a 1-2-0ff Perko battery switch, and a separate engine on-off switch.  The MK I and MK 1.5 boats did not have this feature.  The battery switch accepts current from the two battery banks on my boat, and distributes current to the Engine On-Off switch (and to the main panel).  But what is the purpose of the Engine on/off switch?  

In other words, as originally outfitted, why did Catalina install the Engine On/Off switch?

I look forward to learning more. This is my 4th year on the MKII, after many years with a Mk 1.5.  All of them happy and satisfied years.

--Nelson
s/v Stella
Catalina 36 2069

Nelson Lee, "Stella," 2002 C36, hull 2069, Universal M35BC, berthed Sausalito, CA

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KevinLenard
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Posts: 209

Interesting.  I'm curious about the answer.  Seems to merely force you to think about which house battery (or both) you want to use before turning on battery current to the starter switch. 

On our Mk 1.5 I've added a seperate on/off switch for the third starter battery to further isolate it from being used by the house current (had a couple too many dead banks in the morning on the hook with just two batteries).  They're all charged via a three bank smart charger at the dock, but when I start the engine I switch off the house batteries #1 & 2, start the engine and then turn the house batteries back on to both/all to charge off the alternator while underway. 

I'm a bit of an electrical zombie (my brain shuts off the moment anyone starts explaining amps/ohms/volts/draw), but I have come to understand that the switch must be on to charge the house banks.  Complicates things to remember to make the switch after stopping, but I tried another configuration that was supposed to eliminate the need to touch the switches and it just put the two house batteries on one post of the master switch with the starter on the other.  Not much use as it drew down #1 & 2 together.

Kevin Lenard
"Firefly"
'91 C-36 Mk. "1.5" Tall Rig, Fin Keel, Hull #1120, Universal M-35 original (not "A" or "B")
CBYC, Scarborough, Lake Ontario, Canada

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alfricke
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Posts: 90

Possibly Catalina put in two switches knowing many owners would add the starter battery. On Jubilee...a MK II, I did put in the starter battery. It is fully isolated from the house battery bank and charges separately depending on which bank needs it most. Engine won't start with the engine switch off. There is no key in my ignition system. Putting the house battery switch on "1" activates both house batteries as a single bank. Putting the switch on "both" combines the engine battery and house bank...in the event that somehow the engine battery died...which has never happened to me with this system because I never have the switch on both. LOL I'm not actually sure what the #2 switch position does as it is unnecessary in my system. 

Al Fricke
S/V Jubilee San Francisco Bay
Catalina 36' MkII  #1867
Universal 35-B

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Chachere
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Posts: 825

A guess -- maybe to isolate the engine if doing work on the alternator or starter?
I would help if you could do a schematic, so that we better understood the wiring scheme.  I did one for our boat when we redid the battery wiring arrangement -- see www.catalina36.org/comment/56955#comment-56955 --- where we also have an engine disconnect switch.  In our arrangement, the switch enables us to bypass the start battery if needed.  

 

Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY

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TomR
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Posts: 38

On my 2000 C36 Mkll  #1998 I have a dedicated starter battery with my engine switch. The house batteries have their own switch. The starter switch can be set to #1 just starter battery or #2 (starting only with house battery) or both. Good peace of mind to have a dedicated house battery and the ability to use all battery sources. Shorts happen.

Tom Runiewicz
ObLaDi ObLaDa
Catalina 36 MkII, Wing Keel, Tall Rig
Hull #1998
North East, MD
 

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GaryB
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Joined: 10/26/08
Posts: 570

Nelson, like you, I have just dealt with the old. Currently I just leave my switch on "1" and monitor battery with a "Link" gauge. I have 430 Amp hours and I set the link for 215 so I never run low (or haven't todate). I do have a splitter (may be wrong term) which allows charging both when underway. Alternator is 120 amp. Link says starter battery is fully charged. When tried it does it's job. I use a solar panel to keep batteries charged while away during the week. My last set of batteries lasted 10 years so old seems to work :). 
Anyway here is a link to West Marine ​Installing a Second Battery | West Marine this might answer the why you are looking for in the "Old way" paragraph.

Gary Bain
S/V "Gone With The Wind"
Catalina 36', Hull #: 1056, Year: 1990, Engine: M-35
Standard Rig
Moored: Boothbay Harbor, Maine
Home: Auburn, Maine

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KevinLenard
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Posts: 209

Alfricke is describing the way I rewired our system until I learned the downside -- with both house batteries on the #1 switch you are draining both house batteries in tandem so that you can end up with both totally dead.  I went back to the system Nelson et al are descrbing: using the Engine switch for a new, isolated, starter-only battery (#3) and separating #1 and #2 with the normal battery switch, using the "ALL/BOTH" position to charge them via the alternator while underway.  Using the OFF position to start the engine with the #3 battery only.  This allows me to monitor the charge status of #1 and #2 individually when on the hook and to use one or the other or both to start the engine should the #3 battery die.  We also have two flex solar panels to trickle charge, one on the dodger, one on the bimini.  Having had lots of dead battery issues due to our aging high-draw original Alder Barbour fridge, this set-up allows for maximum flexibility.  (Likely this summer will be the year we replace the original fridge with a cold plate.)

Kevin Lenard
"Firefly"
'91 C-36 Mk. "1.5" Tall Rig, Fin Keel, Hull #1120, Universal M-35 original (not "A" or "B")
CBYC, Scarborough, Lake Ontario, Canada

nelson
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Joined: 6/23/08
Posts: 89

Thanks, everyone, for your responses on this.  I'm glad to see I am not the only one a bit puzzled on this.  I like Kevin's suggestion that the engine switch allows use of a 3d battery bank (even just a solo battery) linked to the engine switch, to preserve starting capacity if the batteries linked to the 1-2-off switch were depleted.  My  boat is not set up that way, although I may change it.  I have a large house bank composed of four 6-volt agm's (390 amp hours) that connects to the 2 position on the battery switch.  A starting battery is connected to the 1 position.  This has worked well for me.  (it is not directly related to this post, but my four AGM 6-volts were recently overheated and rendered "toast"  by a failed charger/inverter while at the dock  So I'm looking at new batteries ($$$) and a charger.  But at least I got 10 years out of the old batts.)

thanks again
--Nelson

Nelson Lee, "Stella," 2002 C36, hull 2069, Universal M35BC, berthed Sausalito, CA

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alfricke
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Posts: 90

Nelson...you are not going to be able to stop this thread!! LOL..I read Kevin's post...it having yet another variation. My thoughts are: 1) we should keep our systems as simple as possible. Needing to switch things around to start an engine, or having to do some switching once at anchor or once underway is not in that category because you have to remember to do those things, even if you are tired or trying to get out of an anchorage that has suddenly turned bad in the middle of the night. 2) To me, the number one priority is to never inadvertently allow a situation where you end up with no way to start the engine...so dead house bank...fine...bad on you, you just didn't monitor them because you were having too much fun...just recharge them. But dead starter battery...never. So make sure the two banks are fully isolated and can be combined only under special circumstances. 3) finally I see little reason to be using just one of the house batteries and not the other. There is a reason to keep them working together and that is that the voltage will stay higher when something is drawing...like the reefer. More voltage is good. Less voltage is bad...not that bad, but more amps will be drawn. (Amps=Watts/Volts) sorry, had to work that in. 4) a good battery monitor is a must...and it is fun to see how the system is working even though it drives the wife nuts when giving her the minute by minute report on amps and volts!!! So, that's why I vote for something like Jubilee's system. I get on the boat, turn both switches on with confidence that my reefer can't affect my starting battery, go on my voyage for a day or month, screw around with my monitor as much as I want, and turn both switches to off when I get back to the dock. 

Al Fricke
S/V Jubilee San Francisco Bay
Catalina 36' MkII  #1867
Universal 35-B

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Chachere
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Posts: 825

Agree with much of Alfricke said. 
What's nice about the system we implemented a number of years back on our boat  -- see www.catalina36.org/comment/56955#comment-56955 and the schematic there -- is that in normal situations there is generally no need to touch the switches at all.   This design comes from Mainesail -- the former C36 owner who is a font of wisdom on things of this nature, see https://marinehowto.com/1-2-both-battery-switch-considerations/ -- and Stu Jackson of the C34 association.

Essentially, at the beginning of the season we switch the main battery switch to "1", and the engine battery switch to "on", and don't mess around with them until the end of the season, when we turn them off.   The charging happens automatically with the house bank being charged directly from the alternator or solar panels or AC charger or some combination thereof, and the engine battery gets charged via the Blue Seas automatic combiner relay.    Set it and forget it.  A picture of our reworked distribution panel is here: www.catalina36.org/comment/57079#comment-57079

We're on our 7th year with a 230AH housebank (2 6V GC batteries), and just replaced our engine start battery after 10 years.   Run the fridge 24/7 whlle cruising (we have solar panels) and never once had a dead battery (either house or engine start).   

Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY

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