Announcement

Collapse
No announcement yet.

Trouble Shooting: 490/4788 DC Problem Need Help

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

    Trouble Shooting: 490/4788 DC Problem Need Help

    Because of personal issues, we have not been to our boat since September. Arrived yesterday to find the DC power faltering. Here is the recap:

    AC dock power working perfect.
    Engine and Genset batteries work fine.
    DC power is fine using engine alternators.
    DC power flickers and falters on house batteries.
    DC meter showing 12.8 volts, but all panel lights flickering.
    The OEM stereo screen flickers off and on even though Stereo Breaker is off.
    Turn on any DC equipment and the volt meter goes to zero and panel goes dark then flickers. Smoke and Carbon Monoxide alarms beep. Item and the volts go back to 12.8 and panel lights stay more steady.
    Turn on LED gangway lights and they work. Turn on two lights above sink and they work. Evidently, under 30 watts and the DC system is OK for a little while. Over 30 watts and it shuts down.

    Professional Mariner 50-3 Battery Charger has solid red light.
    Disconnected charger from batteries, shut AC power, waited, restarted AC, resets the charger, measured 14.6 volts coming out of charger. So that checks out.

    Batteries are Trojan T-105 6 volt x 2, August 2016. Took out batteries and they tested at 6.3 volts or 12.6 volts combined. Took them to battery shop and they tested the same under load. They said the batteries were excellent and fully charged. As they were under warranty, they replaced them anyway. I installed the new batteries and nothing changed.

    Panel. I have shut off every DC breaker and turned them on one by one with no effect on the meter or flickering. I opened up the panel and looked at the yellow ground buss bars and they looked fine. Battery terminals are excellent. Nothing faults or flickers using alternators only on batteries.

    Charger tests good. Batteries are new. Breakers seem good. All equipment and lighting seems to be working fine. DC works great on Alternators or shore power. I have only OEM equipment. No inverter. Charger is charging engine and genset batteries and engines start fine. Its only DC and only when on the batteries. Charger off or on, no difference. No breakers are tripping. Supposedly, no one working on the dock, no power outages, I am the only boat on my slips electrical box, power cord seems fine. I have not added any equipment since I bought this boat 3 years ago. Everything is OEM. Nothing has changed. No rewiring projects.

    Unfortunately we do not have a good marine electrician in our harbor, closest is 60 miles away. I and my dock mates have exhausted our ideas, experience, and tricks. We are stumped. The batteries are NOT drained. A normal short like bilge pump would not cause this. Breakers fine in both pilothouse panel and the main salon panel. Any thoughts or testing suggestions would be greatly appreciated. Its quite frustrating. Feel free to ask questions...

    Thank you.
    Lee
    2007 Meridian 490
    2007 Meridian 368
    1996 2855 Cierra
    1978 Caribbean 26'
    Oceanside, CA

    #2
    Lee,
    I would start at the main DC breaker. Use a VOM to verify voltage at the line (incoming ) side of the breaker with the breaker closed. (Battery charger should be off) If the voltage is not normal start working backwards to the source of the DC breaker feed. The problem can be on the positive or ground side. You could also disconnect the incoming wires (line side) on the DC breaker and then run a temporary feed directly from the battery. If this eliminates the issue you know there is a problem in the factory wiring. Then use the temporary feed to figure out if the positive side or negative side is the issue.
    Gibraltar, Mi.
    1986- 3870- Hino 175's - Just purchased May ,2017
    34' Tollycraft- sold
    88 26' Shamrock/ Diesel
    14' Zodiac Bay Runner

    Comment


      #3
      I'd start by checking grounds at the batteries and all main ground connections you can get to easily.
      Future 4788 Owner
      Charleston, S.C.

      Comment


        #4
        I had something similar happen on my boat. It was a bad ground. I ran a new ground wire from the battery to the DC panel and that fixed the problem.
        I never did find where the bad ground was, so I just left the new wire in place and never had a problem since.
        1999 Bayliner Ciera 2655
        5.7 Bravo 3

        Comment


          #5
          This is where your voltmeter will come in handy. As Sunbird indicated use your voltmeter to trace back


          KEVIN SANDERS
          4788 LISAS WAY - SEWARD ALASKA

          Comment


            #6
            Stereo - is getting power with breaker off. Are any other neutrals hot?
            Irony
            Bayliner 4588
            Portsmouth, NH

            Comment


              #7
              It sure sounds like a bad ground, perhaps a dirty post or two on the batteries. The batteries would read charged, but the power isn’t getting to the cables I would take the battery connections apart and clean them with a battery brush then put everything back together using electrolytic grease. Do the easy stuff first.
              P/C Pete
              Edmonds Yacht Club (Commodore 1993)
              1988 3818 "GLAUBEN”
              Hino EH700 175 Onan MDKD Genset
              1980 Encounter Sunbridge "Misty Blue" (Sold)
              MMSI 367770440
              1972 Chevrolet Nova Frame off Resto-mod in the garage
              Boating on the Salish Sea since 1948

              Comment


                #8
                Originally posted by Kwood View Post
                Stereo - is getting power with breaker off. Are any other neutrals hot?
                There is both switched and unswitched (permanent) DC power; unswitched is intended to keep the stere device's clock going on even when the stereo switch is turned off. You seem to have two problems:

                1) Stereo power is connected wrongly to the permanent DC line. Check and fix this because that will cause the battery to run down if the stereo is left ON, even though the circuit breaker is off. Main radio power should be on the line coming from the circuit breaker. On your radio, there should be 3 lines; BLACK is GND, RED is 12v switched, TELLOW is 12v permanent (intended for the clock function).

                2) Whichever battery is driving the power to your stereo, as it is presently wired, is either low, or has a bad gnd or pwr connection. To identify that battery, simply disconnect one of the battery cables and see if the stereo stops flicking. Then focus on that battery and its connections.

                Good luck.
                Retired, computer expert / executive
                Bayliner 285 Cruiser / Mercruiser QSD 4.2L 320 HP Diesel
                Live in the Bay Area, CA, USA, boat in Turkey
                D-Marin @ Turgutreis in Bodrum/Turkey
                bdervisoglu8@gmail.com
                bulent@pacbell.net

                Comment


                  #9
                  Solved! Thank you for all the good suggestions. It was a corroded ANL 300 amp fuse box & fuse. $40 at West Marine and everything is good.

                  I forgot about this fuse as its tucked in back of the battery box and hard to see. This has prompted me to purchase a second battery box and 2 more six volt Trojans. I will also relocate the ANL fuse box to a better location, away from lazzerrette water intrusion areas.

                  Thanks again.
                  Lee
                  2007 Meridian 490
                  2007 Meridian 368
                  1996 2855 Cierra
                  1978 Caribbean 26'
                  Oceanside, CA

                  Comment


                    #10
                    Originally posted by LeePTI View Post
                    Solved! Thank you for all the good suggestions. It was a corroded ANL 300 amp fuse box & fuse. $40 at West Marine and everything is good.

                    I forgot about this fuse as its tucked in back of the battery box and hard to see. This has prompted me to purchase a second battery box and 2 more six volt Trojans. I will also relocate the ANL fuse box to a better location, away from lazzerrette water intrusion areas.

                    Thanks again.
                    Sounds good; Still, please verify that with the DC MAIN OFF, your radio/stereo is not powered. If it is, it's power connection is wrong and leaving it open may lead to run down battery.
                    Retired, computer expert / executive
                    Bayliner 285 Cruiser / Mercruiser QSD 4.2L 320 HP Diesel
                    Live in the Bay Area, CA, USA, boat in Turkey
                    D-Marin @ Turgutreis in Bodrum/Turkey
                    bdervisoglu8@gmail.com
                    bulent@pacbell.net

                    Comment


                      #11
                      LeePTI,

                      I'm very happy you've resolved your issue. However your original post creates some difficulty for me still.

                      1) as indicated by others any device not properly shutdown by it's breaker should be checked and the issue resolved.

                      2) You state "DC power is fine using engine alternators." I just can't see how any 12V system I've designed and built would continue to work with a bad fuse connection from the battery. This may deserve further investigation also.

                      Of course it's extremely difficult to diagnose and resolve electrical issues on a forum such as this since we have only the information that is reported.

                      RB Cooper ny

                      Comment


                      • LeePTI
                        LeePTI commented
                        Editing a comment
                        Sorry I never responded. A major life change has been taking priority over boating. I don't completely understand what all went wrong with my electrical system, but 6 months later and no issues.
                    Working...
                    X