Registered users don't see ads
  1. Need help with the forums? Have a question, suggestion, or complaint? Let us know!
  2. What happened to the mobile app??? Updated 10/15: now two options.

1/BOTH/2/OFF Switches Thoughts & Musings

Discussion in 'Musings With Maine Sail' started by Maine Sail, Jan 31, 2012. Add this thread to a FAQ

  1. Les Noble

    Les Noble

    Joined Sep 11, 2016
    4 posts, 0 likes
    Via Marine 42
    ud houston, tx Rockland, me
    I am figuring all this out as I go along and utilizing great advise from Main Sail/Compass Marine, but I am still in the "I don't know what I don't know" stage. I am a little foggy on battery size cable. The original configuration was 3 Trojan T-1275 150 AH batteries where one was designated as the starter batter. Two ON/OFF switches, when both are on, the batteries are parallel. All this is wired with AWG 2/0 battery cable even to the engine.
    The new configuration is combine all 3 into the house bank and add a starter battery ~650 CCA and a third ON/OFF switch as per Maine Sail example. My question is should I wire the whole setup with 2/0 or use 4AWG for starter battery to battery/switch/engine. I will terminal fuse the starter as per M.S. as well. Is there a possibility of burning up the 4AWG if starting from the house bank when the starter battery has failed?
    I am also not clear on AH vs CCA. In the Bluesea circuit wizard, the option for Battery CCA is CCA or MCA. If a circuit is originating from the house bank, there is no CCA rating only AH. I need to go back and read Calder.
     


  2. Maine Sail

    Maine Sail Moderator

    Joined Feb 6, 1998
    10,018 posts, 184 likes
    Canadian Sailcraft 36T
    US Casco Bay, ME

    Stick with 2/0 wire as it will allow you to properly size your fusing to the max ampacity of the wire, and accommodate emergency engine starting from the house bank. On a 42' boat you're likely looking at a 300A or larger fuse...

    The bottom line? If you intend to fuse both banks, and either bank could be called upon for starting, then you need wire that can handle the fuse rating that can handle starting loads or windlass or bow thruster or inverter charger etc.... Also larger wire will get more voltage to the starter and your starter will have more cranking ability and live a healthier life. If you have a large inverter-charger 2/0 might not even be large enough unless the run is short...
     


  3. Les Noble

    Les Noble

    Joined Sep 11, 2016
    4 posts, 0 likes
    Via Marine 42
    ud houston, tx Rockland, me
    One other wrinkle in the implementation is the boat is all aluminum and everything is isolated ground. I have an Echo Charger to install and have been thinking about the ground. I have the 3 on/off battery switch setup and the house and starter ground are separate unless the switches are set to parallel. Should the single ground lead from the Echo charger go to each ground battery terminal or make a common bus bar like the attached drawing. I can't find the link to the borrowed image below, but the my plan is the same with the addition of isolated ground. I may have missed the mark in choosing the Echo as the common ground bus bar defeats the purpose of isolating the ground through the switches. Any help is appreciated.

    upload_2016-9-30_19-40-5.png
     


  4. mitiempo

    mitiempo

    Joined Sep 28, 2008
    917 posts, 7 likes
    Canadian Sailcraft CS27
    Ca Victoria B.C.
    I see no reason for isolating the grounds of each battery from the other. On a metal boat it is important of course to keep all grounds isolated from the hull.
    While I have not tried it I believe that neither the Echo Charge nor an ACR will operate with isolated battery grounds.
     


  5. Les Noble

    Les Noble

    Joined Sep 11, 2016
    4 posts, 0 likes
    Via Marine 42
    ud houston, tx Rockland, me
    I don't see a reson not to have a common ground to the batteries either. But, I don't know what I don't know. What are pro's and con's of having a common ground for the batteris on a isolated ground system? In this case, my system would be as the drawing, just remove the ground from the dual switches.

    Thanks for the input!
     


  6. Maine Sail

    Maine Sail Moderator

    Joined Feb 6, 1998
    10,018 posts, 184 likes
    Canadian Sailcraft 36T
    US Casco Bay, ME
    Your drawing shows common negatives for the banks and this is correct..

    On a metal boat the batteries/neg/Earth are often isolated from the ship and the engine should be as well. This requires an alternator that is isolated ground as well as a starter motor and engine alarm circuit. Creating an isolated ground system is not easy. This is a typical drawing for a 30-45' sailboat using three ON/OFF switches..

    [​IMG]
     


  7. Rodd

    Rodd

    Joined Jan 22, 2008
    104 posts, 0 likes
    Pearson 424
    US East Hampton,NY
    Ideas for trim ring when installing 1-2-Both switch in a hole that is larger than the new switch-
    I am installing a new Blue Sea switch to replace a failing Guest switch. Trouble is, the new switch is about 1 half inch narrower in diameter than the old switch. The new switch only sticks out about a quarter of an inch beyond the original wood mounting surface, so using a 1/2 inch teak cut out doesn't allow the switch to stand proud. What I am looking for is what to use to as a trim ring around the new switch that will cover the larger cut out hole and be thin enough to allow the switch to come all the way through the hole. Sorry for the difficult explanation!
    Any ideas Gents?
     


  8. SFS

    SFS

    Joined Aug 18, 2015
    754 posts, 94 likes
    Hunter 31
    US Tampa Bay
    If you are willing to paint it, and have the material lying around, you could make a trim ring from epoxy, by just allowing some epoxy to cure in the bottom of a plastic container with the appropriate diameter. You can control the thickness of the piece by adjusting the volume of material in the container. Then cut the inner hole (for the switch) to size. How big is the original hole?
     


  9. Rodd

    Rodd

    Joined Jan 22, 2008
    104 posts, 0 likes
    Pearson 424
    US East Hampton,NY
    Original hole is 4 inch diam. now I need 3 5/8 diam.
    Thanks.
     


  10. SFS

    SFS

    Joined Aug 18, 2015
    754 posts, 94 likes
    Hunter 31
    US Tampa Bay
    Shouldn't be hard to find a plastic container with about a 4/5 inch diameter bottom. You may want to thicken the epoxy, but strike a balance between the extra strength that would give and the difficulty of working (drilling or sanding) the final product. West Systems 406 filler is strong, but can be tougher to sand than other choices. A hole saw should be available in 3 5/8ths.

    Another option would be to have one fabricated in the material of your choice, but that means $$.
     


  11. Rodd

    Rodd

    Joined Jan 22, 2008
    104 posts, 0 likes
    Pearson 424
    US East Hampton,NY
    Thanks SFS. I will try to find a piece of thinner teak and cut out the right size hole. I'm only afraid that a thin enough piece of teak to allow the switch to mount properly would be hard to use a saber saw with and might crack while I am cutting out the circle.
     


  12. Maine Sail

    Maine Sail Moderator

    Joined Feb 6, 1998
    10,018 posts, 184 likes
    Canadian Sailcraft 36T
    US Casco Bay, ME


    I have used the Blue Sea 8080 and 8280 to solve a lot of switch mounting issues.. Alternatively I have also used Front Panel Express..

    While not inexpensive these solutions almost always costs less & look more professional than most other alternatives...
     


  13. nameless

    nameless

    Joined Sep 22, 2013
    21 posts, 0 likes
    Catalina 30
    US NOB Norfolk W5CDR
    I second the Front Panel Express recommendation. I had purchased an ELCI switch assembly thinking I could swap it for the standard A/C switch in a Paneltronics A/C panel. Not so fast; I needed a custom panel. I drew up a plan on their free software, sent it in, and BINGO my panel arrived several days later! See attached:
    ELCI Panel copy.jpg
     


  14. John61CT

    John61CT

    Joined Jan 7, 2017
    43 posts, 0 likes
    beneteau 36
    US eastern US new london
    OK, resurrecting and back to the original topic, "birds eye view" of overall system design, and specifically an appropriate setup for manual and automatic switches. Sorry it's a bit long and no diagram, all I got's my phone here.

    I'm purposefully ignoring details like existing setup, device/bank physical locations, wire sizes, fusing, what wires go where exactly, specific devices other than the manual switches, etc.

    =======
    My house bank is Primary, carries ALL Loads, including cranking usually.

    The much smaller Backup (starter) bank/battery normally has NO Loads on it whatsoever, except for cranking the engine during Primary (house) bank failures, or when I've run it down too much to crank the engine - hopefully rare to never for either. I acknowledge the idea of having a Backup large enough to run a subset of House Loads for a while, but won't discuss that now, KISS.

    I'm pretty close to the Three ON/OFF Switch Configuration

    http://www.pbase.com/mainecruising/image/154153780.jpg

    but I want to keep the "Primary/normally-unused Backup" principle, rather than the more traditional House/Starter design.

    Backup starter is kept floated via Echo or ACR off Primary (actually my Alt is dual output, but I think that's also OT for now).

    All non-Alternator charging Sources are on the Primary bank. For now that's just the Shore charger; I may in future add solar or wind, magic Unity free power from water, etc :cool:

    See Switch A below for Alternator-based sources.


    And links to the right Blue Sea switch for each would be most appreciated.

    ---------
    Switch A: big red 1/2 key, switches *all* Loads & Sources together

    1 labeled "Isolate backup bank" (normal, Primary is connected) vs 2 "use Backup" (rare exceptions, Primary disconnected). Note ACR/EC bypasses this isolation for charging the Backup (starter).

    I don't see any reason I'd ever need to Combine banks here, can have a personal power jumpstart pod for belt & suspenders, could even use jumper cables in a pinch I s'pose.

    And I don't see the use of a global "ALL Banks Off", in fact it would be dangerous if someone did that while Alt was HO'ing right?

    Speaking of Alts, and I am very unsure about this: Alt-based Sources (in future maybe also a smaller dedicated genset, off-topic for me here) are tied in, along with "All Loads", to a Common point on this Switch A.

    Other than this requirement for a Common for the Alt(s), this would just be a very robust 1/2 switch, make before break correct? Please let me know (link?) if a suitable switch type like this exists.

    And if I've lost the plot here, please tell me why this is not a good idea. If it's just $$, I think I'd be willing to spend a bit more (relay, solenoid?) to ensure I never take a running $$ Alt off Battery Load.


    ---------
    Switch B: ON/OFF for all House Loads, like a Master breaker, but only for ALL loads not essential for running the engine, safety, comms, navigation etc, AKA no Boat Loads. This switch could in fact be a circuit breaker, right?


    ---------
    Switch C: Same sort, but for all Boat Loads which are safe to turn off when not going anywhere long-term.

    Only exceptions would be an "always on" circuit for 24x7x365 security/safety systems (no need to discuss that list here). These to be hardwired to same Switch A Common point as the Alt(s)?


    ---------
    Switch X: one ON/OFF for each charging Source's circuit, to isolate in case of that Source's drastic failure, including one for the combining ACR/EC. Suggestion please for doing a manual "combine charge" if the ACR/EC fails?

    For Alternators, this just turns off Field current? Or should it be set up in conjunction with an ON/OFF for AO to isolate the Alt completely; if so, do I need some sort of a delay in there?

    For Shore power, both before and after the charger. Dunno about wind & solar?

    ---------
    Switch ?: *really* not sure on this, but I think would like to be able to selectively isolate expensive and potentially sensitive electronics from the starter's cranking noise /spikes /brownout, and maybe from other even bigger "noisy" loads, e.g. washer/drier, big microwave or induction cooker?

    Is it possible to filter/isolate these noisy Loads there?

    If not, then one solution, rather than going back to House/Starter, might be to take these devices off the two main House and Boat Load circuits and move them to the "always on" group circuit.

    Give them a smaller, dedicated "Sensitive Secondary" battery/bank, maybe auto-isolated from Primary by something like a switched relay triggered by starter ignition ON, or the oil pressure switch, if that's a prereq for cranking.

    Obviously just noob spitballin' here. . .

    All comments and suggestions would be most appreciated!
     


    Last edited: Jan 7, 2017
  15. John61CT

    John61CT

    Joined Jan 7, 2017
    43 posts, 0 likes
    beneteau 36
    US eastern US new london
    OK, in my travels via Google, I read MS's excellent bulletin on the critical factors of remote voltage sensing. Google "YOU SHOULD ONLY SENSE VOLTAGE AT THE BATTERY TERMINALS IF THE ALTERNATOR IS ALSO DIRECTLY CONNECTED TO IT"

    So it looks like I may need to think more about my idea of attaching the alt output to the Common on Switch A (1/2 Primary vs Backup).

    Pending advice, I'm not yet quite willing to scrap it completely though. What if?

    Super-robust gauge wiring and switch there, located right at the Primary bank, so actual voltage drop is truly miniscule?

    and/or

    put the voltage sense at the same Switch A Common point?

    and since we've got a very smart AO regulator (assume MC-614) we can upward tweak voltage just a hair to get back to optimal?

    ------
    If it turns out this isn't going to work, then another idea is to take advantage of the fact my Alt (Balmar 94-160) is dual-output, and therefore can run separate AO wires to Primary (w/ sense) and Backup starter banks.

    Pros: no risk of Alt running without being connected to a sink for its output (boom bad)

    100% correct compliance with best practice wrt the above critical issue

    eliminate need for combining via echo/ACR


    Cons: have to be same-charge-profile banks

    (bigger issue) cuts cooling capacity at the Alt in half compared to bussing the outputs, as per Balmar docs.

    any feedback on this and the previous previous post would be most welcome, sorry to be so verbose
     


  16. Maine Sail

    Maine Sail Moderator

    Joined Feb 6, 1998
    10,018 posts, 184 likes
    Canadian Sailcraft 36T
    US Casco Bay, ME
    This is fine, if that is how you want it, but why do you want it that way?

    Again a reserve battery is fine, if this is how you want to operate it, but you don't have to. This is really for those who already have a 1/2/BOTH and want to keep it. It simply avoids needless switching.


    If you're going to have a reserve battery there is really no sense in not having one that could run house loads. We are talking about 15-20 pounds difference...

    Then why do you want to operate it like a 1/2/BOTH? If you have the ability to isolate house & start loads might as well run with it.


    Why??

    This can be done with any of the switch configurations you choose.


    DO NOT use the dual output feature. Bus the two outputs together and use it as one alternator.

    ALL charge sources including the alternator should be on house. It makes no sense to run the alt to a battery you never plan to use...


    If you want the three-switch configuration wire it properly with three switches. If you want a 1/2/BOTH install a 1/2/BOTH...

    The three switch configuration has nothing to do with "combining banks" it is all about isolation, redundancy and the ability to "cross-connect" either bank to power and start the entire boat in an emergency.... Without the third switch you lose the isolation, redundancy cross-connect benefits of that system.

    For a 36' boat this is an ABYC requirement and most surveyors and insurers will want to see a way to isolate all the batteries on-board vi a battery switch. They will also be looking for proper over current protection for the house bank. As for alternator diode protection from you or guests, you run it direct to the house bank with its own fuse and an engine space mounted "alternator service disconnect" switch that no one but the service-tech will ever touch..

    If you want any level of performance charging them you run all charge sources direct to the house banks always-on bus or the physical battery terminal.


    To be honest I don't really know what the "plot" is?? You seem to want the 1/2/BOTH use switch system but then say you want a three switch config but with only two switches then you are trying to re-invent the wheel on switching & charging..?? I am honestly a bit confused by what you are actually asking.


    What you've said you want above is not this and "all loads" are "all loads" except "boat loads...........?????....?


    KISS? Now we are at three switches and none of them really suitable for bank redundancy or isolation or emergency situations?

    You really need to describe your usage of the vessel, daily Ah consumption, crusing expectations, dock stored or mooring and what you expect from the system. You really also need to draw a diagram to avoid all the confusing back & forth... None of this is really making much sense for a 36' vessel...


    The alt should have its own dedicated "alternator service disconnect switch". A solar controller can have a switch either on the output or input but this will vary by manufacturer.

    If a battery charger fails it just fails to charge or over charges. The outputs are diode isolated and I've yet to see a failure that caused back feed. No switch necessary but a fuse within 7" of the battery bank is required and this could always be removed it you felt it necessary.

    A toggle switch for the brown ignition wire to the reg can be installed and it is never a bad idea. I have one on my engine panel. Herein lies the confusion, you started out by asking about battery bank switching, which is what this thread is about, and now we are down to small toggle switches for regulator power......??? You probably want to collect your thoughts, do lots more reading, and start a thread for this...

    Again this thread is about battery switching so from here forth I will remain on-topic...

    This can be done but we are now waaaaaay beyond "KISS"

    It can get very costly and complex to properly isolate "sensitive electronics" from system noise. The bottom line is that it rarely matters if the system is properly wired to begin with.

    ???

    Again ????

    You're going to want to start your own thread. Please give us a drawing and a clean well thought out list of what you want to do with the boat and what you expect from your system. Also include where the DC system is now and what you are building from and hoping to end up at..

    Eg:

    Boat is at a dock during the week with shore charging available
    We both have Mondays off so every weekend we cruise for three days
    We take a three week vacation/cruise once per year
    The vessel consumes on average -100Ah's each day
    We have a 160A alternator & external regulator
    Would like to add solar in the future but not now
    We would like to go two to three days between charging when cruising
    I want my electronics protected from voltage transients
    I want dedicated starter battery and house battery or I want to use one bank for everything
    Boat needs to pass insurance surveys and be in compliance with safety standards

    etc. etc...
     


  17. Maine Sail

    Maine Sail Moderator

    Joined Feb 6, 1998
    10,018 posts, 184 likes
    Canadian Sailcraft 36T
    US Casco Bay, ME
    Please create a new thread for this discussion. This thread is about battery switching...
     


  18. John61CT

    John61CT

    Joined Jan 7, 2017
    43 posts, 0 likes
    beneteau 36
    US eastern US new london


  19. John61CT

    John61CT

    Joined Jan 7, 2017
    43 posts, 0 likes
    beneteau 36
    US eastern US new london
    > The three switch configuration has little to do with "combining banks" it is all about isolation, redundancy and the ability to "cross-connect" either bank to power and start the entire boat in an emergency

    >If you want the three-switch configuration wire it properly with three switches.

    >If you want a 1/2/BOTH install a 1/2/BOTH...

    here's my separate thread for discussion of "creative variations"

    http://forums.sailboatowners.com/in...y-switches-layouts.182986/page-2#post-1347024
     


    Last edited: Jan 11, 2017
  20. Jackdaw

    Jackdaw

    Joined Nov 8, 2010
    5,961 posts, 591 likes
    Beneteau First 36.7 & 260
    US Minneapolis MN & Bayfield WI
    Maybe this has been touched on somewhere in the last 10 pages, but a useful mod on Beneteau's with their usual 3-switch setup with a switch to break BLACK as shown....

    [​IMG]

    Is to re-task the 'Black' switch as Maine's 'emergency combine' and re-wire. I used liquid tape to re-cover the black handle, and a label maker to re-label.
     



Noflex Sewage Treatment
Treat sludge and odor problems in holding tanks.
Winch covers
Any brand, every size, any color!
Flexible steel chafe pads
Innovative new product made of flexible, laser cut stainless steel. Must see!
Gray Enterprises port gasket
Stop winter leaks. Compare our price!