Announcement

Collapse
No announcement yet.

1988/38 Hot Water Heater...12V Connection...What's up with that...?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    1988/38 Hot Water Heater...12V Connection...What's up with that...?

    You know when you get that burning question that you just can't wait for an answer...?

    Well...here it is...

    My water heater has a 12V input coming from a switch wired to my port/start battery...Another lead (black) goes somewhere, presumably negative.

    Sorry I don't have a model number as I won't be on the boat til the weekend. If you can help without knowing the model number, thank you...otherwise I'll wait til I get back on the boat.

    What do you think that 12V is for...? I tried searching for dual voltage 12/120V heaters...nothing. I did find 12V heaters (300W). Then I ran across a dual voltage 12/120V heater element (two elements built into one fitting)... Maybe one of the previous owners did a conversion...?

    What are your thoughts...?
    1988 3888
    Twin Cummins 6BT's 210hp
    Onan 8KW

    #2
    I have never seen nor heard of a marine water heater that offered a 12 VDC input.

    In order for a 12 VDC element to heat water, the amperage and wattage would be tremendous, and would be terribly inefficient !
    Rick E. Gresham, Oregon
    2850 Bounty Sedan Flybridge model
    Twin 280 HP 5.7's w/ Closed Cooling
    Volvo Penta DuoProp Drives
    Kohler 4 CZ Gen Set

    Comment


    • Nickp
      Nickp commented
      Editing a comment
      Not that I would buy one but Whale and Seaward both make them...primarily for outboards. Several forums also discuss 12V heaters (and their inefficiency)...

    #3
    Interesting. I’ve never heard of a 12 volt powered element for a water heater. If one does exist I can’t imagine it’d be very effective. The previous owner could have ran the 12 volt circuit for something els in theat area maybe?
    Dave
    Edmonds, WA
    "THE FIX"
    '93 2556 5.7 Bravo II 2.0:1 18 1/4x19 P
    (.030 over-Vortec top end-part closed cooled)
    The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
    Misc. projects thread
    https://www.baylinerownersclub.org/f...56-gctid789773

    Comment


    • Nickp
      Nickp commented
      Editing a comment
      Thanks, Dave...yeah, it's definitely wired to heater on the other side of the switch. Closer examination later today just in case...

    #4
    Things that make ya go hmmmmmmmmmm. Can't wait for the pics.
    1998 BL Ciera 2655 Sunbridge LX (Special Edition)
    "Sea Flights"
    5.7L 2bbl w/Thunderbolt Ignition and raw water cooling
    A​​​​​​lpha I Gen II Sterndrive/1.45:1 gears
    M15.25 X 15P Black Max prop
    MFG Extra's - A/C, Fresh Water Engine Flush port, HWH and Windlass
    Docks @ Punta Gorda, Florida

    Comment


      #5
      About the last thing I’d want powered by my starting batts would be a water heater! Are you sure this isn’t a case of mistaken wire identification?
      Jim Gandee
      1989 3888
      Hino 175's
      Fire Escape
      [email protected]

      Comment


        #6

        Baring the circuit from the battery bank (12V input coming from a switch wired to my port/start battery), is it possible that the 12 is actually followed by a 0? ........... I.E. 120?
        Is it also possible that the V is actually followed by AC? .......... I.E. VAC?


        Update:
        Interestingly enough.... I just found these for use with outboard engines:

        https://www.whalepumps.com/marine/pr...-Electric-Only

        https://www.amazon.com/Whale-Gallon-.../dp/B00XCIJN78


        At 300 watts, that's a 25 amp load.
        I can't imagine that being very efficient.


        When the OP could use his Cummins 6BT engine coolant to heat water, there is no need for this type of water heater!

        If this is what he has, I would remove it and install a two-way Marine Water Heater in it's place!
        He would now have engine coolant provided hot water, and/or Shore Power/Generator electric powered hot water.


        .
        Rick E. Gresham, Oregon
        2850 Bounty Sedan Flybridge model
        Twin 280 HP 5.7's w/ Closed Cooling
        Volvo Penta DuoProp Drives
        Kohler 4 CZ Gen Set

        Comment


        • pgiconch
          pgiconch commented
          Editing a comment
          Well, dang nab it. Those pics do it. But I'm still thinking "hmmmmmmmmmm".

        • Nickp
          Nickp commented
          Editing a comment
          Agreed...the heater does have both 120V and starboard engine coolant for heating water...

        #7
        Originally posted by pgiconch
        Well, dang nab it. Those pics do it. But I'm still thinking "hmmmmmmmmmm".
        Me too. Why would anyone chose that style for this boat?
        Rick E. Gresham, Oregon
        2850 Bounty Sedan Flybridge model
        Twin 280 HP 5.7's w/ Closed Cooling
        Volvo Penta DuoProp Drives
        Kohler 4 CZ Gen Set

        Comment


        • Nickp
          Nickp commented
          Editing a comment
          No argument here...thanks

        #8
        OK - after all of my hmmmmmm (and Hawinnnnng) I've decided that there are some viable reasons to go with the HWH which Nick has (and like Rick found). While I may not choose it for a larger boat model which has a generator, I guess it could be a viable alternative to an AC only model or having to have it plumbed to the engines for those of us that have smaller boats. And unlike me who lives in southern Florida where the cold water is always warm, perhaps it would be good while out on the hook, sans a generator, to be able to warm the water up a bit, especially on those cold or chilly days. BUT - and HOWEVER - I certainly wouldn't want it connected to a start battery even if it is "efficient" and doesn't draw the battery down too much. I would ensure I had a dedicated battery(ies) just for that HWH and/or other use while on the hook.

        And, since it doesn't seem to provide for an alternative AC input while at dockside, it is probably only a practical solution for those "weekenders" who rarely use the hot water system anyway and would need to use it much except for a very occasional outing. If they in fact do come in dual voltage, then I would be back to hmmmmming and hawinnnnng!

        My best advice Nick would be to determine if it is 12V only, and if so rewire it to a dedicated battery and not either of your start batteries. So if you don't use HW much, it may not be an issue for you, but you may want to move it off the start battery and on to your house battery.
        1998 BL Ciera 2655 Sunbridge LX (Special Edition)
        "Sea Flights"
        5.7L 2bbl w/Thunderbolt Ignition and raw water cooling
        A​​​​​​lpha I Gen II Sterndrive/1.45:1 gears
        M15.25 X 15P Black Max prop
        MFG Extra's - A/C, Fresh Water Engine Flush port, HWH and Windlass
        Docks @ Punta Gorda, Florida

        Comment


        • Nickp
          Nickp commented
          Editing a comment
          Thank you...but there really is no reason for it to be on 12V even on house bank. When engine is running, it will make plenty of hot water...when at the slip, there is plenty of 120 to keep water hot. And with the genny available for other purposes while on an extended stay on the hook it makes it even more useless.

          I'm with you...there doesn't seem to be a reason for it to be connected to 12V on this boat. I agree, might be good for a less configured boat AND with a dedicated battery as you suggested.

        #9
        All good thoughts...thank you...

        The wire definitely is 12V and was connected to start battery...I disconnected it since I didn't know why it was there. The heater does have plumbing for engine heating and it does work very well...

        Certainly at 300W it couldn't possibly make enough hot water and the current draw can't be good for the battery, especially hooked up to the start battery. The switch has been off the whole time I've had the boat...so far, no harm done.

        I will be at the boat later for model number and pics...

        Thanks for your thoughts...

        1988 3888
        Twin Cummins 6BT's 210hp
        Onan 8KW

        Comment


        • pgiconch
          pgiconch commented
          Editing a comment
          Ahhhhhh...the plot thickens. It has engine thermal and 120V connectivity! Wow. That is something. Then as you say, probably no reason whatsoever for the 12V. Unless -- you are on the hook, the engine(s) supplying the thermal heat, AND the genny all crap out at the same time! And you just feel you gotta have a hot shower right then and there.

          You know I'm grinning from ear to ear as I type this!

        #10
        ..........
        Originally posted by Nickp View Post
        Thank you...but there really is no reason for it to be on 12V even on house bank.
        I completely agree.

        When engine is running, it will make plenty of hot water..
        Yes.... my SS 12 gallon Water Heater will give me plenty of hot water in about 45 minutes cruise time.
        In 1 hour, there is more than enough.


        when at the slip, there is plenty of 120 to keep water hot. And with the genny available for other purposes while on an extended stay on the hook it makes it even more useless.
        Agreed.


        The wire definitely is 12V and was connected to start battery..
        What was the PO thinking???

        .I disconnected it since I didn't know why it was there. The heater does have plumbing for engine heating and it does work very well...
        Interesting!
        Of the ones that I found and linked us to, I don't recall them offering engine coolant heating since they were intended for use on boats with OutBoard engines.


        Certainly at 300W it couldn't possibly make enough hot water
        It probably could..... but it may require several days!


        and the current draw can't be good for the battery, especially hooked up to the start battery.
        That's the part that killed me!


        The switch has been off the whole time I've had the boat...so far, no harm done.

        Suggestion:
        See if the 12 vdc heating element is similar to a 120 vac element with regard to the way that it fits into the tank.
        If so, perhaps it could be swapped out for a 120 vac element.
        Of course you would need to include the 120 vac WH style thermostat and high temp cut-out.


        I will be at the boat later for model number and pics...

        Thanks for your thoughts...
        Rick E. Gresham, Oregon
        2850 Bounty Sedan Flybridge model
        Twin 280 HP 5.7's w/ Closed Cooling
        Volvo Penta DuoProp Drives
        Kohler 4 CZ Gen Set

        Comment


        • Nickp
          Nickp commented
          Editing a comment
          Thanks, Rick...heater already is 120 and works well...no additional conversion should be necessary. But, if the 12V element fits the same way, maybe a spare 120V element would be good to install...in case of a "hot water state of emergency"...LOL...

        #11
        A friend here at my marina has a 4588 with duel water heaters. One is 120v and the other is 12v. He spends a month out on a mooring leading up to July 4 and his boat is equipped with solar panels. He uses the 12v water heater exclusively during that time and rarely starts the generator. They do work out under the right circumstances.
        Greg A.
        1994 4788
        "Simplicity"
        2002 Capri 175
        "Little GFI"
        Boat on the Sac/San Joaquin Delta

        Comment


          #12
          Originally posted by Jim_Gandee View Post
          About the last thing I’d want powered by my starting batts would be a water heater! Are you sure this isn’t a case of mistaken wire identification?

          Finally got down to the boat...this time I cut all the wire ties and did a better job of tracing the wires...wasn't easy...PITA to put everything back together...

          Jim..you were right...mistaken wire identity...

          Heater is a marine Atwood EHM11-SM 120VAC 10.5gal...

          Now for another step towards completing my doc library...finding the manual...

          Thanks all for putting up with the wild goose chase...but I now know there ARE 12V heaters for marine use...who'da thunk...
          1988 3888
          Twin Cummins 6BT's 210hp
          Onan 8KW

          Comment


          • pgiconch
            pgiconch commented
            Editing a comment
            Hey - I had fun!!!! And we all (well most of us) learned something new so the time wasn't wasted.

          #13
          Nick, that’s actually good news! Glad you were able to trace it down!
          Jim Gandee
          1989 3888
          Hino 175's
          Fire Escape
          [email protected]

          Comment

          Working...
          X