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    House battery going flat after 5 hours

    Can anyone assist, I have 2 house batteries in my 3055 and of late the low battery alarm goes off in about 5 hours. The battery supplyer told me to check with multi meter which I did and they both show 12-13.5 volts and when charger is on they jump to around 14volt.

    #2
    If one of the batteries is going bad that may pull down both as they are in parallel. what is the voltage when the alarm goes on. Verify that you don’t have a constant load that drains them. See if you can have the batteries tested. Also, keep monitoring the battery voltage and before the low battery alarm goes on, check the voltage and then separate the parallel connection between the batteries and check individual battery voltages directly at the battery posts. If one battery is bad the good one may recover its voltage.
    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
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    Comment


      #3
      A battery voltage measurement must be taken at a minimum of 30 mins after a charger has been disconnected otherwise you will be measuring residual charge on the battery. That being said a battery cannot measure more than 12.6-12.7 otherwise something is wrong or there is residual charge current. A 12.0v reading translate to 75% discharge. This is a good read and the voltage chart will give you a good idea of state of charge. https://www.emarineinc.com/Marine-Ba...aintenance-101

      That being said, I agree with MontVista. Probably a bad battery or battery cell. How old are the batteries and have you ever found them flat on a regular basis. A flat battery sitting for a month will be toast.
      Cheers, Hans
      2007 Carver 41 CMY
      Twin Volvo D6-370
      Montreal, Canada
      Midnight Sun I Photos

      Comment


        #4
        Originally posted by gazza25
        Can anyone assist, I have 2 house batteries in my 3055 and of late the low battery alarm goes off in about 5 hours. The battery supplyer told me to check with multi meter which I did and they both show 12-13.5 volts and when charger is on they jump to around 14volt
        .

        Gazza, when checking lead/acid battery voltage (after charging), the battery being checked should have been at rest for 8 hours or more. Some manufactures suggest 24 hours.
        This is due to the chemistry and temperature changes that occur during the charging.
        After having been at rest, good healthy 12 volt lead/acid battery should read 12.6 volts when in a full SOC (state of charge).

        And yes, I do agree that if one battery is bad, it will affect the good battery.



        As for monitoring your HLBB (house load battery bank)...... a battery voltage reading is not an accurate means of monitoring.
        To accurately monitor your HLBB, you will want to monitor Amp Hours...... Amp Hours in, and Amp Hours out.
        To do this, you would need a battery monitoring system that incorporates the use of a Shunt Resistor, such as one the Xantrex, Victron or BEP units.
        The Shunt Resistor interrupts the Negative return path to the bank being monitored, and only that Negative return for bank being monitored.

        The system reads amps that pass through the shunt resistor, then via the electronics, converts and displays this data into usable information re; Amp Hours IN/OUT!








        In order to size your HLBB in terms of Amp Hours, you would want to first calculate your anticipated daily loads in terms of Amp Hours.
        You would then size your HLBB so that it will provide 200% of that, understanding that you will not want to draw it down further than 50% between charges.
        This is where the Shunt Resistor style monitor comes in.
        For example: if your daily loads equal 100 AH, you would size your HLBB as to offer 200 AH.
        The monitor will track Amp Hours and will display your consumption on the screen.

        Some people use the analogy of a Shunt Resistor monitor acting as though it is a fuel gauge for batteries, allowing us to ensure that we have enough fuel left in the tank!
        The actual reason for this type of monitoring is..... batteries don't like to be drawn down more than 50% of their AH capacity.


        Good luck, and I hope you find a quick resolve.

        .
        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


          #5
          Lets make this easier.

          The job of your house batteries is to supply voltage to your house loads.

          Turn off your charger, and let them supply your house loads as designed.

          Check the battery voltage. It should be 12 volts under load, and decreasing in voltage a bit as they discharge.

          After 5 hours when your battery voltage alarm goes off what is the exact voltage? Basically is your battery voltage alarm working properly?

          Here is an example...

          My house bank goes to 12.0 volts very quickly after the charger is turned off due to the normal house loads.

          After 10 hours of supplying my boats loads it is down to 11.7 volts, which is just fine.

          Some would submit that battery voltage under discharge means nothing...

          I would submit that since the batteries job is to supply current at 12 volts or thereabouts, that battery voltage under load is the only actual performance based test out there. Does the bank do its job???

          This is how I tested batteries (in conjunction with hygrometer checks) while working on remote microwave and fiber optic sites for many years, and this technique is the fruits of the multiple week long battery maintenance classes that my employers had me attend over the years.

          KEVIN SANDERS
          4788 LISAS WAY - SEWARD ALASKA
          where are we right now​​​​​​???​

          https://share.findmespot.com/shared/...j23OquWOj2N3Xe

          Comment


          • Centerline2
            Centerline2 commented
            Editing a comment
            I agree... "Load" testing in conjunction with the use of a hydrometer is the only way to tell the real health of the battery.

            there are other ways of load testing the batteries (load tester), and the "health" is NOT the same as the State Of Charge.... even a bad battery can show it has a full charge, UNTIL a load is placed on it, then the truth comes out...

          #6
          Without knowing how much you are taking out of the batteries, it is pretty hard to say if it is right or wrong. Because I live on batteries the entire season at anchor somewhere, I monitor my batteries closely. As a general observation if they truly go flat in 5 hours under normal use, replace them. A system as mentioned that measures amp hours in and amp hours is the only good way to know what condition your batteries are in. I find measuring voltage while under constant use, well useless.
          Started boating 1955
          Number of boats owned 32
          Bayliners
          2655
          2755
          2850
          3870 presently owned
          Favorite boat. Toss up. 46' Chris Craft, 3870 Bayliner

          Comment


            #7
            Originally posted by dmcb View Post
            .............. A system as mentioned that measures amp hours in and amp hours out is the only good way to know what condition your batteries are in. I find measuring voltage while under constant use, well useless.
            Doug is talking about house bank battery state of charge..... and yes.... ditto his comment.
            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


              #8
              Originally posted by 2850Bounty View Post

              Doug is talking about house bank battery state of charge..... and yes.... ditto his comment.
              True, but state of charge is a measurement of a working battery banks remaining capacity. Voltage is not a good method of determining the capacity remaining in a battery bank, for that I use a SOC meter Xantrex Link Pro is my choice.

              If the batteries go to a low voltage state, no matter that the calculated remaining charge left in them(as long as it’s not zero ), they are faulted.

              KEVIN SANDERS
              4788 LISAS WAY - SEWARD ALASKA
              where are we right now​​​​​​???​

              https://share.findmespot.com/shared/...j23OquWOj2N3Xe

              Comment


                #9
                Kevin, both Doug and I are talking about battery monitoring using Amp Hours as the base line, as apposed to looking at a voltage reading alone.
                With a known HLBB Amp Hour capacity, a true battery monitoring system (shunt resistor style), will track AH consumed and AH charged back into the bank.
                That is a much more meaningful means of HLBB management.
                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


                  #10
                  Originally posted by 2850Bounty View Post
                  Kevin, both Doug and I are talking about battery monitoring using Amp Hours as the base line, as apposed to looking at a voltage reading alone.
                  With a known HLBB Amp Hour capacity, a true battery monitoring system (shunt resistor style), will track AH consumed and AH charged back into the bank.
                  That is a much more meaningful means of HLBB management.
                  I agree completely, and use a SOC meter that incorporates a shunt on my boat to monitor my house bank status.

                  In this case the OP has a house bank that is going flat after 5 hours. By going flat, his reported symptom is low voltage.

                  Logic says that to troubleshoot this, follow the symptom, IE the low voltage.

                  The true test of a battery system is the voltage of the bank after removing X number of amp hours. If the battery bank will not supply a reasonable voltage after removing it’s capacity of amp hours then it is defective and needs replacing.

                  The only measurable component to the OP’s issue that we are not aware of at this point is load. He could theoretically be drawing out enough amp hours to make his battery bank fully discharge, but I do not think that is the case (butI am not certain). He has also reported a significant variation in voltage between cells. This is a concern, as he probably has one of more cells that are defective, making the whole bank in need of replacement.

                  In practice testing a battery bank is MUCH easier than folks make it out to be.

                  Turn the charger off, with normal house loads on.

                  Wait... while checking voltage occasionally.

                  If the voltage drops to a low voltage condition too soon, then the batteries are either being asked too much of them, or the bank is defective. If you have a ongoing history of your battery bank and for example know that you can run for say 20 hours before the voltage gets too low, and now you can only run 10 hours, then well... logic says that either the bank is defective, or your loads increased.

                  For me with a SOC meter this is even easier. If the bank is at 50% using the amp hours counting method, and the battery voltage is much lower than my 11.7 reading on my 8 year-old bank, then it’s time for a new battery bank.

                  KEVIN SANDERS
                  4788 LISAS WAY - SEWARD ALASKA
                  where are we right now​​​​​​???​

                  https://share.findmespot.com/shared/...j23OquWOj2N3Xe

                  Comment


                    #11
                    The true test of a battery system is the voltage of the bank after removing X number of amp hours. If the battery bank will not supply a reasonable voltage after removing it’s capacity of amp hours then it is defective and needs replacing.

                    But unknown here is just how much he is removing from the batteries. The batteries could be perfectly good but the bank isn't large enough. That is the beauty of a system that monitors amps in and amps out along with the capacity of the battery bank. I have found voltage in a system at use to be quite useless.
                    Started boating 1955
                    Number of boats owned 32
                    Bayliners
                    2655
                    2755
                    2850
                    3870 presently owned
                    Favorite boat. Toss up. 46' Chris Craft, 3870 Bayliner

                    Comment


                      #12
                      Originally posted by dmcb View Post
                      The true test of a battery system is the voltage of the bank after removing X number of amp hours. If the battery bank will not supply a reasonable voltage after removing it’s capacity of amp hours then it is defective and needs replacing.

                      But unknown here is just how much he is removing from the batteries. The batteries could be perfectly good but the bank isn't large enough. That is the beauty of a system that monitors amps in and amps out along with the capacity of the battery bank. I have found voltage in a system at use to be quite useless.
                      "I have found voltage in a system at use to be quite useless".... to test the health of any battery quickly, the only way to do it is with a load test... this is where the full charged battery is placed under maximum load for a certain amount of time (seconds) and then measuring the voltage of it WHILE UNDER THAT LOAD.... its far from useless, but the only way it can be done without many taking days to do it.

                      counting amps in/out to know the current SOC can be done without a meter as well, but its a lot more intensive and takes an extreme amount of dedication and longer to get readings that can be used to determine the current SOC.... as I said before, SOC and "battery health" are two very different things....

                      but as to the OP's battery issue, its my opinion that installing and amp counter at this immediate time for his problem is putting the cart before the horse type of thing.

                      its an easy, cheap and quick test to check to see if the batteries are bad with a load test and hydrometer, but lots more expensive and takes longer to install a meter to count amps in/out, and then take the time to monitor it long enough to learn anything useful, and then likely finding out the batteries are indeed bad (which is probable due to the time frame that he SAYS the problem started happening)

                      I do strongly agree an amp counter is a good thing to have for anyone who spends a lot of time on their boat, and uses a lot of power during that time, but one has to have good batteries for the system to be of any real use, and where these problems seem to have just started happening, I think a load test is the first thing that should be done to insure the batts are good....


                      NU LIBERTE'
                      Salem, OR

                      1989 Bayliner 2556 Convertible
                      5.7 OMC Cobra - 15.5x11 prop
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                      2014 Ram 3500 crew cab, 6.7 Cummins
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                      Comment


                        #13
                        Perhaps we are talking about two different things here.

                        1........ Gazza says that in about 5 hours, his HLBB voltage is dropping below what would be acceptable. I can only assume that he has seen better performance in the past.
                        So, if this bank is now under-performing, he may have a bad battery, or both may be bad.
                        This requires load testing.

                        2...... I started the conversation regarding a more meaningful means of managing a HLBB..... i.e., using a AH monitoring system rather than a voltage reading.

                        If battery testing only....... yes, do a load test.
                        If battery monitoring....... use the shunt resistor style monitoring system and track Amp Hours.




                        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


                          #14
                          Lets say you have a battery with a sulfated cell. Sulfating is where the battery goes down all the way due to a load present. The sulfation, in layman's terms, is where the lead is damaged and combines with the sulfuric acid and causes, a corrosion for lack of a better term, and prevents that cell from charging properly or giving energy out. Ig you connect a heavy current charger to the battery, maybe, just maybe you can cause the sulfation to flake off and the battery works again, but at very reduced output (in amp-hours). Now, in this state it is very prone to sulfate further. As one who worked an engineer for a battery charger company and designed many back up battery supplies for communications equipment, there is NO WAY to correct sulfation from the outside of a battery. The plates are damages and lead is missing.

                          That said, what I would do:
                          1. Get a ammeter and put it in the line at the battery. This is with all devices turned off. If you get more that 100 mA, something is drawing current and can be found and repaired.
                          2. use the ammeter to determine the current draw of the devices you normally run. This is the (very roughly) the amp-hours being drawn. Compare this with the battery specs. The draw should be a maximum of 50% of the battery capacity. Using the whole or near whole AH of a battery severely shortens its life. 5 years, I would replace it.
                          3.When batteries age, AH goes down. There is no chart to tell how much and when, due to all battery's are different and all boats (and boaters) use them differently.

                          I had a absorption fridge in the boat when I bought it. It sucked 10 amp hours at DC when running. I went to 2 golf cart batteries (6V) and got 220 AH. Those batteries lasted 7 years. Note: if you have a friend who is a weight lifter, bring him when you get the batteries. They weigh 80-90# each. The fridge failed and my Norcold compressor one is happy with a 110 AH deep cycle.

                          As I said in previous posts "Ever try to rope-start a 5.7 V8?"
                          Captharv 2001 2452
                          "When the draft of your boat exceeds the depth of water, you are aground"

                          Comment


                            #15
                            "I have found voltage in a system at use to be quite useless".... to test the health of any battery quickly, the only way to do it is with a load test... this is where the full charged battery is placed under maximum load for a certain amount of time (seconds) and then measuring the voltage of it WHILE UNDER THAT LOAD.... its far from useless, but the only way it can be done without many taking days to do it.

                            True but we are talking about everyday boat usage. Most don't have load test equipment and rely on a gauge. That to me gives false readings and false readings are useless. Turn on the ignition switch. Look at the amp gauge. Turn on a cabin light and look again. There is no way that little light causes a battery discharge as much as shown.
                            Started boating 1955
                            Number of boats owned 32
                            Bayliners
                            2655
                            2755
                            2850
                            3870 presently owned
                            Favorite boat. Toss up. 46' Chris Craft, 3870 Bayliner

                            Comment


                            • Centerline2
                              Centerline2 commented
                              Editing a comment
                              I agree 100%.... the load test has to be a a very heavy and known load for a known amount of time to tell if the battery is bad.... a light load will not tell us anything useful.
                              sometimes a load test alone can lie to us in the same way a hydrometer test alone can lie to us, but when used together, the truth will be known...

                              i also agree the everyday boater doesnt need to check the health of his batteries like a boat that has large multiple battery banks.... but the more batteries in the bank, the more it makes sense to own a load tester...
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