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  • Trouble Shooting Help: Sudden high charge AMPERAGE

    (Edit: Title is incorrect, should read 'Sudden high charge AMPERAGE. Unable to save edits.)

    I am looking for any assistance on troubleshooting a recently noticed spike in reported charging amperage. The full Issue details can be found following the set-up details.

    Set-up details:
    - Battery Bank: Two 220Ah sealed, AGM Full River brand GC2-6V batteries wired in sequence for a 12V, 220Ah bank (bought new, 1 year ago).
    - Charge controller (CC): Renogy rebranded Tracer 40amp (bought second hand 1 year ago, previously unused).
    - Panels: 4 Renogy branded 100W, wired in two parallel circuits of two panels in sequence 2p2s(?) (bought secondhand 1 years ago, previously unused).
    - Batteries feed out into one breaker panel with appropriately sized blade fuses from which the load is distributed.
    - CC is monitored by an MT-5 remote monitor (RM) which displays panel V, battery V, input amps, temp and a few other stats. RM Readings tend to corroborate with multimeter readings.
    - System is mounted inside a converted sprinter van which is outside and driven constantly, so vibration and temp change may be a factor.
    - There is a 40amp DC marine breaker between the panels and the CC and between the CC and the battery bank.
    - Load: two LED light circuits, two USB outlets, a fan, a 10amp cigarette outlet into which a DC fridge is plugged.

    The issue: The system has been working flawlessly for the past eight months. The most intense load is a Dometic fridge that pulls about 3amps during its cycle. Power has been supplied whenever we need it and the batteries have been charging fully every day.

    Previously, with full sun, I usually noticed (reading from the input amps provided by the MT-5 remote monitor) a small spike in amperage, around 3 - 4amps in the morning, then the input settles down to < 1amp for much of the day, as long as there is no load. Two days ago (with no obvious changes in temp, illuminance, or other factors) the charge controller started reporting up to 9 amps charging amperage for an extended period of time.

    The battery bank seems to get up to about 13.8V then hold there. The charge controller then increases the amps, but no increase in battery voltage seems to occur. The battery voltage readout is corroborated by a multimeter, i.e. when it reads 13.8 on the MT-5 it reads 13.8 on the multimeter. Individual batteries in the bank have appropriate voltages. Edit: The Volts do eventually go up, it just takes much longer than it used to, even a few days ago.

    Attempted troubleshooting.
    - Thinking there might be a short in some of the wires I removed all the blade fuses from the fuse box but the high amps remained, which suggests that this is occuring prior to the fuse box.
    - I tightened down some connections (mostly on the breakers) and cleaned the plastic case of the batteries. There is not apparent corrosion on the battery terminals, and the terminals bolts seem as tight as possible.
    - I hit the breaker to the panels, then the breaker to the batteries, in hopes that this would reset any issues in the CC. No charge was noticed.
    - No cable fraying has been noticed, nothing is warm to the touch and all wire terminals seem adequately crimped (i.e. do not separate when pulled.)

    I am at a loss as to where the problem might be arising. Tips for other places to check, or any further details that I could provide would be really appreciated.

    Thanks,
    Sam
    Last edited by sammmoss; 07-25-2019, 09:26 AM.

  • #2
    You could have a load coming on, which is sucking power from the panels, and not from the batteries. Amps go up, voltage stays the same. Do you have a way to monitor your loads ?

    The amps are going somewhere, or else the voltage HAS to go up. Maybe the fridge is going bad and compressor lugging down ?
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    • #3
      Originally posted by Mike90250 View Post
      You could have a load coming on, which is sucking power from the panels, and not from the batteries. Amps go up, voltage stays the same. Do you have a way to monitor your loads ?

      The amps are going somewhere, or else the voltage HAS to go up. Maybe the fridge is going bad and compressor lugging down ?
      Hi Mike thanks for the reply, please refer to my original post:

      [I]Attempted troubleshooting.
      - Thinking there might be a short in some of the wires I removed all the blade fuses from the fuse box but the high amps remained, which suggests that this is occuring prior to the fuse box.[/I]

      I believe removing the blade fuses from all loads should point the the problem being upstream of the loads, also there is no correlation between fridge cycle and the amp pulls, i.e. whether the fridge is running or not the amps being pulled are high. Also I clarified the battery behavior a bit, (Edit: The Volts do eventually go up, it just takes much longer than it used to, even a few days ago.)

      Is it possible for loads to still draw from the battery if the blade fuses are removed from the fuse box?

      thanks,
      Sam

      Comment


      • #4
        If the batteries weren't so "new" I would suspect an internal issue with them.

        Usually if all of the "load" fuses have been removed there shouldn't be any battery draw. But sometimes any "short" in the wiring can create a resistance load that will drain the battery.

        Comment


        • #5
          Originally posted by SunEagle View Post
          If the batteries weren't so "new" I would suspect an internal issue with them.

          Usually if all of the "load" fuses have been removed there shouldn't be any battery draw. But sometimes any "short" in the wiring can create a resistance load that will drain the battery.
          Thanks Suneagle.

          Can you recommend any techniques (with a multimeter or other tool) to pinpoint where a potential short might be located?

          Comment


          • #6
            Originally posted by sammmoss View Post

            Thanks Suneagle.

            Can you recommend any techniques (with a multimeter or other tool) to pinpoint where a potential short might be located?
            To be safe I would totally unwire each component and then use either the voltmeter or ohm meter to check for shorts or grounds on each leg of the circuit.

            You may just have s "sneak" path to ground on the 12v side which will drain the battery.

            But as I first mentioned, the likely suspect are that the batteries that can no longer get back to full 100% SOC without drawing more charging amps.

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            • #7
              Originally posted by SunEagle View Post

              To be safe I would totally unwire each component and then use either the voltmeter or ohm meter to check for shorts or grounds on each leg of the circuit.

              You may just have s "sneak" path to ground on the 12v side which will drain the battery.

              But as I first mentioned, the likely suspect are that the batteries that can no longer get back to full 100% SOC without drawing more charging amps.
              Great, thanks for the tip.

              Comment


              • #8
                Are those batteries totally out of balance? After at least a 4 hour rest after charging, what are the *individual* voltages of each 12v battery?

                If they are more than 0.1V different from each other (say one at 12.5v and the other at 12.7v,) then we have a problem. Use your own voltmeter for this test, don't rely solely on the monitoring gauge. If they are out, then I'd be sorely tempted to pull them, and charge each one *individually* to full, and then rewire back into your original parallel config.

                Avoid the ladder-type connection, even with just two batteries in parallel. From your description, it sounds like you may have your positive and negative main power leads connected to just one of the batteries. Rewire so that you have a positive coming from one of the batteries, and the negative going to the OTHER battery. It does make a difference, even with only two batts.

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                • #9
                  Originally posted by PNjunction View Post
                  Are those batteries totally out of balance? After at least a 4 hour rest after charging, what are the *individual* voltages of each 12v battery?

                  If they are more than 0.1V different from each other (say one at 12.5v and the other at 12.7v,) then we have a problem. Use your own voltmeter for this test, don't rely solely on the monitoring gauge. If they are out, then I'd be sorely tempted to pull them, and charge each one *individually* to full, and then rewire back into your original parallel config.

                  Avoid the ladder-type connection, even with just two batteries in parallel. From your description, it sounds like you may have your positive and negative main power leads connected to just one of the batteries. Rewire so that you have a positive coming from one of the batteries, and the negative going to the OTHER battery. It does make a difference, even with only two batts.
                  Thanks for the reply. I have not tried this yet, but will give it a shot.

                  I believe your assumption about the battery configuration is incorrect: the positive main lead goes from the CC into one 6V battery, then a strap connects the first battery to a second battery, then the negative main led goes from the second battery back to the CC. Therefore: two 6V batteries wired in series to form a 12V battery bank.

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                  • #10
                    My take on this
                    The bank of 220ah can swallow 22 charging amps and still within 1/10th of charging rate. Maybe you don't have sufficient charging amps to sustain a min charging rate during cycle.
                    With time you run into a very slow deficit charging, not providing sufficient absorb time, maybe sulphating a bit. Now the battery takes that bit of extra current to charge due to increased resistance. Since they are agm's and you can't check the gravity, I suggest you invest in a shunt type meter/monitor that is able to measure amps in and amps out. Set up correctly, taking efficiency and peukert effect in consideration, a shunt will be pretty accurate. Only then you will know for sure that , what you take out, you recharge back, BEFORE the CC switches to float , on a daly basis use.

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                    • #11
                      Originally posted by Raul View Post
                      My take on this
                      The bank of 220ah can swallow 22 charging amps and still within 1/10th of charging rate. Maybe you don't have sufficient charging amps to sustain a min charging rate during cycle.
                      With time you run into a very slow deficit charging, not providing sufficient absorb time, maybe sulphating a bit. Now the battery takes that bit of extra current to charge due to increased resistance. Since they are agm's and you can't check the gravity, I suggest you invest in a shunt type meter/monitor that is able to measure amps in and amps out. Set up correctly, taking efficiency and peukert effect in consideration, a shunt will be pretty accurate. Only then you will know for sure that , what you take out, you recharge back, BEFORE the CC switches to float , on a daly basis use.
                      Raul this is novel advice, but I am going to ask for some clarification here.

                      Can you clarify a bit more on what 'the bank can swallow 22 charging amps and still [be] within 1/10th charging rate.' means? Does this mean that < 22 charging amps is a normal amount of current?

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                      • #12
                        My bad, I meant 1/10 of total capacity. Which happens to be the optimum charging rate of 22A.

                        Comment


                        • #13
                          Originally posted by Raul View Post
                          My bad, I meant 1/10 of total capacity. Which happens to be the optimum charging rate of 22A.
                          Great. Thank you for the clarification Raul.

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