How to run boat at night when on water

Discussion in 'Sport Cruisers' started by Mark Searay, Dec 16, 2019.

  1. Mark Searay

    Mark Searay Member

    82
    Nov 10, 2019
    Sydney Australia
    Searay Sundancer 375
    Mercruiser 6.5L x 2
    Hi
    As a newbie to boating , what’s the best way of running lights etc at night without destroying batteries?
    Is it recommended to run generator at night instead of running off batteries ?
    Any tips would be greatful
    With thanks
     
  2. Stee6043

    Stee6043 Well-Known Member

    Jun 1, 2015
    West Michigan
    1997 Sundancer 400
    7.4L Gassers
    I guess that will depend pretty heavily on what you consider "etc". :)

    A properly maintained set of house batteries should have no problem running your lights, a fridge or two and the occasional sink/head visit for a night or two without running the generator. If you're having battery capacity issues in the AM with these kinds of overnight loads you likely need some new batteries...or perhaps there are other electrical issues that could use some attention.
     
    QT1 and JVM225 like this.
  3. RollerCoastr

    RollerCoastr Well-Known Member

    Nov 15, 2007
    Cedar Point, OH / Miami, FL / MacRay Harbor, MI
    1997 400DA
    340HP 7.4 Mercruiser Bluewaters
    Garmin 741, 742, 8212, 24HD, Intellian I2
    1999 280BR
    Twin 250HP Merc 350 Alpha Ones
    Run the genny until right before bedtime to ensure batteries are fully-charged.
    • Convert the lights to LED
    • Minimize the time pumps run by:
      • doing washing etc. while genny is running in the evening
      • ensuring the the vacuflush system has no leaks (or shut it off at night)
      • ensuring the check valve in the sump is good so it doesn't cycle
    • Fill fridge and freezer with cold/frozen and dense items (beer cans and ice packs, frozen food etc)
    • Turn temp of fridge to a very cold setting while genny is running, then back up to a safe but higher temp off after shutdown
    • Avoid opening the fridge door until genny is running again in the morning
    Start the genny again in the morning to re-charge batteries, heat water, run pumps, make coffee etc.

    With healthy batteries and care, this routine can maintain 12V power indefinitely while running the genny 2-4 hours per day.
     
  4. sbw1

    sbw1 Well-Known Member

    Oct 10, 2006
    West Michigan
    This is listed in my signature
    This is listed in my signature
    We never ran our genny unless we needed it for heating IMG_4230.JPG or cooling. The batteries were robust enough to handle lights, TV, and stereo for several hours. Our refrigerator had a cold plate so it didn't run much.
     
  5. Express 390

    Express 390 Active Member GOLD Sponsor

    472
    Sep 14, 2018
    South Shore of Long Island NY
    1986 SeaRay 390 EC
    1993 SeaRay 290 DA single 7.4 /Bravo 2
    1992 SeaRay 230 DA 4.3LX Alfa drive
    Twin 454 Crusaders inboards 4 blades
    Like Stee6043 said a properly maintained 12 volt system should handle the demand with in reason. I can go out all day, run the Radio, Refrig, and whatever lighting needs to be used spend the night and be fine in the morning. And if you have too start the generator for a little while turn on the charger and put a little life back in the batteries !
     
    JVM225 likes this.
  6. Stee6043

    Stee6043 Well-Known Member

    Jun 1, 2015
    West Michigan
    1997 Sundancer 400
    7.4L Gassers
    Rarely will you find more practical, useful advice on the internet than "fill the fridge with beer cans". This is forum gold, people. :):):)
     
    gasketguy, Kwik, joeyleggz and 11 others like this.
  7. RollerCoastr

    RollerCoastr Well-Known Member

    Nov 15, 2007
    Cedar Point, OH / Miami, FL / MacRay Harbor, MI
    1997 400DA
    340HP 7.4 Mercruiser Bluewaters
    Garmin 741, 742, 8212, 24HD, Intellian I2
    1999 280BR
    Twin 250HP Merc 350 Alpha Ones
    anything worth doing is worth doing right... :D
     
    gasketguy, Kwik, joeyleggz and 5 others like this.
  8. electricaldoctor

    electricaldoctor Well-Known Member TECHNICAL Contributor PLATINUM Sponsor

    May 14, 2008
    Thousand Islands, Rockport, Ontario.
    1988 390 EC
    454 Mercruiser Gassers
    I had (4) 6 Volt Golf Cart Batteries in my 390 and could go out on a 4-day long weekend without any issues. (and I don't drink beer)
     
  9. Creekwood

    Creekwood Well-Known Member GOLD Sponsor

    Apr 26, 2009
    Oakville and Georgian Bay, Ontario
    '97 330 Sundancer, Raymarine C80 suite with radar, Mercury 310 Hypalon w/8hp Yammie 2stk
    2X 454 carbs w/ vDrives
    On my 330 I have my house bank replaced with two 6v golf cart batteries in series. They are 232 Amp hour rated. I have all of my lights replaced with LEDs now and a new Nova Kool refrigerator, which reduces power consumption. The fridge uses 5.2 amps while running so assuming 25% running time (I doubt it runs that often) there is over 7 days of power to run the fridge alone. Lighting and stereo during the day reduce that capacity of course and I would never run it down to zero. LED anchor lighting maybe is 3 watts = .25amps (20 watts = 1.7 amps if you don't convert LED). So you will consume about 2 amp hrs overnight each night if you leave LED anchor lights on for 8 hrs (14 for regular bulbs). So anchor lighting is not consuming much.

    I can easily be at anchor for a 3 day weekend without running the engines (I do not have a generator) and have enough to start the engine that shares the house bank at the end of the weekend (although it does turn over slowly).
     
  10. JVM225

    JVM225 Well-Known Member GOLD Sponsor

    Apr 8, 2008
    Farmingdale, NY
    2002 410 Sundancer, Monaco Edition.
    3126 Cats.
    Solid info!
    When we sleep on the hook we just run the genny for cooking, AC, TV etc. until it’s time to go to bed.
    Swapping all the bulbs in the cabin and cockpit courtesy lights to LED will cut down significantly on how much you draw and give you additional peace of mind.
     
    Express 390 likes this.
  11. Malve

    Malve New Member

    2
    Sep 26, 2019
    2016 Sundancer 310
    Mercruiser 350 Mag
    Another newbie question in the topic:

    When you are out and off shore power and you want to use your generator...
    Do you leave everything in the position they are in for battery usage or do you switch it all back like you’re on the 110?

    Thanks.
     
  12. ttmott

    ttmott PhD in OCD GOLD Sponsor

    Apr 3, 2012
    Space Coast Florida
    2006 52 Sedan Bridge
    Cummins QSM11
    I believe the most important thing is to know your boat and it's systems including it's capabilities and condition. Only with this can one determine the answer to these questions. For example, the generator on my boat pretty much runs from the time we disconnect from to the dock until we reconnect because of the AC and DC power the boat demands for us to fully enjoy it. I also know that the batteries in their current age/condition can carry the boat on anchor through the night easily without the generator running and not have to change the boat's power configurations. Every boat will have differing results consequently the need to know your boat...
     
    Henry Boyd likes this.
  13. Steve OD

    Steve OD Member

    62
    Oct 26, 2017
    West Yarmouth, MA
    Sol Searchin'
    1996 330 Sundancer
    7.4 L V Drives
    Did you have to change your battery charger as well?
     
  14. b_arrington

    b_arrington Well-Known Member GOLD Sponsor

    Feb 21, 2007
    Setauket, NY
    2018 Back Cove 34
    Cummins QSB 6.7 480
    I think you are asking if folks turn on different DC circuits when they turn on the generator? So they are not so much in battery conservation mode?

    For my part I don't specifically energize specific DC circuits just because I'm on the generator. I use the genny to either charge the batteries or run specific AC-only equipment like the 3 air conditioner units, the ice maker, or the stove. The fridges and microwave work on AC/DC and an inverter, respectively. I generally turn on DC circuits or items when I want to use them and turn them off when I don't.

    I guess the only thing I do specifically with the genny running is to turn on both AC legs of the panel. That lets me use the air con, the battery charger, and will auto switch the fridges from DC to AC power. I have to do that because I turn off the AC circuits when disconnecting the shore power.

    Not related to your question, but I have some generator start up / shut down practices I follow. When starting I always let the generator come up to operating temperature before gradually turning on any AC loads - minimum 150 F. Then I turn on the AC load gradually. When stopping the generator I also always turn off the loads and allow the generator to cool down for a few minutes before shutting down. During these few minutes of no-load operation the operational temps will typically fall from 170 F to 150 F. It's better for the health of the generator.
     
  15. Creekwood

    Creekwood Well-Known Member GOLD Sponsor

    Apr 26, 2009
    Oakville and Georgian Bay, Ontario
    '97 330 Sundancer, Raymarine C80 suite with radar, Mercury 310 Hypalon w/8hp Yammie 2stk
    2X 454 carbs w/ vDrives
    I had replaced it earlier when the old Promariner 30 was starting to fail. I replaced it with Pronautic 1240P which does a great job.
     
  16. be_prepared

    be_prepared Active Member PLATINUM Sponsor

    327
    Oct 12, 2015
    Mattapoisett, MA
    2002 Sea Ray Sundancer 340DA
    Twin Mercruiser Horizon 8.1 inboards
    Great thoughts in here, especially the "fill the fridge with beer" insight. When not at a marina, we seem to fall into similar habits to what's discussed here. Typically in the morning when we wake up, the genny goes on for making coffee, using the microwave or stovetop for breakfast, running the hot water heater for showers and cleaning up those breakfast dishes. During that, we have the batteries getting some juice. Most of the day genny is off, unless it's really humid and "she who must be obeyed" needs the A/C. In the evening, genny is usually back on to have hot water for rinsing off after swimming, making dinner, and cleaning up. Again, a couple hours that way at night and in the morning seems to do the trick for several days on the hook.

    (Our endurance issue on the hook is usually fresh water, not electrical power, wish we had a bigger tank.)
     
  17. Creekwood

    Creekwood Well-Known Member GOLD Sponsor

    Apr 26, 2009
    Oakville and Georgian Bay, Ontario
    '97 330 Sundancer, Raymarine C80 suite with radar, Mercury 310 Hypalon w/8hp Yammie 2stk
    2X 454 carbs w/ vDrives
    If I am going for extended periods on the boat, I bring along some of those large square spring water jugs that I just refill with tap water from home. They fit in storage spots here and there and can be used for drinking, cooking, dishes etc. and help extend the 40gal tank. I also "shower" in the lake if we are not at a marina, which is a nice advantage of Great Lakes boating in our area.
     
  18. JVM225

    JVM225 Well-Known Member GOLD Sponsor

    Apr 8, 2008
    Farmingdale, NY
    2002 410 Sundancer, Monaco Edition.
    3126 Cats.
    12 volt stuff stays where it is. My fridges and lights are easily handled by the batteries for full days or overnights on the hook.
    The genny gets turned on mostly for showering, cooking and climate control in the cabin.
    If the genny is running when the motors aren’t, I flip the breaker for the battery charger on.
    My routine:
    I shut off all the 110 breakers before unplugging from the dock.
    If I decide to use the generator away from the dock the 110 breakers are in the off position before I start the generator. I let it run for a minute or so after starting, then I start switching 110 breakers on for the stuff I want to run.
    When it comes time to turn the generator off I shut 110 breakers off, then shut generator off.
    The 110 breakers stay switched off until I’m plugged in back at the dock.
     
    Last edited: Feb 7, 2020
    Express 390 likes this.
  19. Malve

    Malve New Member

    2
    Sep 26, 2019
    2016 Sundancer 310
    Mercruiser 350 Mag
    These responses are REALLY helpful. This was just the kind of information I was looking for.
     
    b_arrington likes this.
  20. Mark Searay

    Mark Searay Member

    82
    Nov 10, 2019
    Sydney Australia
    Searay Sundancer 375
    Mercruiser 6.5L x 2
    Yes, when Gen is on, I continue using all 12v stuff. I do notice the main draw is the 2x bar fridges
    I want to replace them with a more efficient fridge but unsure what the exact or best replacement is
    II have a 2005 375 (340DA) Sundancer & believe the NovaKool are the best replacements.
     

Share This Page

Show Sidebar