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  • #16
    [QUOTE=mapmaker;117351]The purpose of the "Remote battery voltage sensor port" is NOT for you to measure voltage at that location. It is for a pair of wires to run to the battery so the controller knows the battery voltage through a means other than the power cable.

    --mapmaker

    Oops, a case of split focus by me - very busy at moment clearing up after a once in 60 year storm, 510mm (just over 20") of rain in three days, gale force winds, non stop rain for five days, already had a lot of rain earlier in the month, ground sodden and the gales uprooted six large trees, one of which landed on my house. Two other large trees snapped off about head level. We live on a hillside 150metres above sea level, but many parts of the region suffered major flooding. We were cut off several days with washouts and slips on our road, and telephone service out for 7 days. The region without grid power for ten days. Have had 8 days of fine weather since, so very busy clearing up. Have large stack of wood from only two trees to split up for firewood, and still six trees to go!
    Plus I should now be building the deck and installing French doors on the sunny side of my house ready for summer, and having the distraction of the new battery bank and controller not performing, has been getting in the way.

    So, I made an assumption that the remote voltage port was for the voltage meter, just had a close look, and the cables for the voltage meter are in fact wired into the controller sharing the outlets from controller to battery.

    Sorry to alarm you! Just had another read of the controller operation manual, and apart from saying there is an optional cable available for connecting to the remote battery voltage port, nowhere does it say what it is for! Which raises the question, should I have one?
    Last edited by Sub; 07-28-2014, 12:41 AM. Reason: Incorrect info

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    • #17
      Originally posted by Sub View Post
      Just had another read of the controller operation manual, and apart from saying there is an optional cable available for connecting to the remote battery voltage port, nowhere does it say what it is for! Which raises the question, should I have one?
      Quite a storm! Hope the falling trees didn't hit your solar array.

      If you have proper cabling, you don't need a remote voltage sensor. 'Proper' means thick enough that there is insubstantial voltage drop across the cable.

      The reason I was asking is because if you have a remote voltage sensor installed, that could be contributing to your problems. My best guess about your problems is that you have a bad connection somewhere in the power wiring. It could be a bad crimp in a cable. It could be almost anywhere, but I suspect it to be in the battery cables and/or shared wiring of the inverter and controller.

      When you get your digital multimeter, the first thing to do is measure the voltage directly on the output terminals of the controller. Also measure the voltage directly on the input terminals of the inverter. And measure the voltage directly on the battery terminals.

      Try to do this under several conditions:
      It would be good to know those numbers when the system is relatively at rest (at night with minimal load).

      Also get those numbers while there is strong solar charging (it would be nice to get the measurements when the OPD event occurs, but for the purpose of this troubleshooting, it is not necessary.)

      And finally, get those numbers with a heavy load (run the microwave at night while you take the measurements)

      If you can get these measurements, that would be a very good first step in troubleshooting your problem.

      In the meantime, you can do a visual inspection of all connections. If you have an infrared thermometer, you can look for hot spots... you must do this when there have been strong currents (charging and/or discharging) for awhile. You can also re-torque connections. It wouldn't hurt to disconnect the battery cables and clean the battery terminals and cable connectors.

      --mapmaker
      ob 3524, FM60, ePanel, 4 L16, 4 x 235 watt panels

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      • #18
        Thanks, Mapmaker



        The battery cables are 15mm in diameter (which I think equals AWG 0000) so should be thick enough.

        I have asked my daughter's partner (who owns a large electrical business) to send me a new digital voltage meter, so will do the checks you recommend when it arrives. Will post result. If any thing needs fixing will call in an expert to do it.

        Thanks for your patience with someone who has limited technical expertise!

        Fortunately the tree fell on the south side of the house so missed the solar water heating panels on the north side of the roof. No room for PV panels on roof so they are on a sturdy platform about 40 meters from the house. Some people did lose PV panels in the storm - someone not far from us had reportedly $25K worth of solar ripped off by the wind. And separate from the storm, worryingly, a neighbour about 2 kilometres up the road from us had their solar system stolen last week while they were away.

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        • #19
          Is it a problem with the CC?

          Originally posted by mapmaker View Post

          When you get your digital multimeter, the first thing to do is measure the voltage directly on the output terminals of the controller. Also measure the voltage directly on the input terminals of the inverter. And measure the voltage directly on the battery terminals.

          Try to do this under several conditions:
          It would be good to know those numbers when the system is relatively at rest (at night with minimal load).

          Also get those numbers while there is strong solar charging (it would be nice to get the measurements when the OPD event occurs, but for the purpose of this troubleshooting, it is not necessary.)

          And finally, get those numbers with a heavy load (run the microwave at night while you take themeasurements)

          If you can get these measurements, that would be a very good first step in troubleshooting your problem.

          In the meantime, you can do a visual inspection of all connections. If you have an infrared thermometer, you can look for hot spots... you must do this when there have been strong currents (charging and/or discharging) for awhile. You can also re-torque connections. It wouldn't hurt to disconnect the battery cables and clean the battery terminals and cable connectors.

          --mapmaker
          1. It took a couple of weeks for the new digital multimeter to arrive. So, I visually checked all joints, put my hand on connection points, no kinks and no heat detected. Became increasingly concerned about frequent OVDs when sun shining brightly. Contacted my nearest solar installer hoping he could trouble shoot things for me, but he is reluctant to work on other people's installs - also probably a bit annoyed I didn't purchase through him. He did say two things; firstly that on his installs he always uses one set of cables for to and from the battery bank - thus disagreeing with the supplier's opinion that the inverter and controller should not share the same cables to the battery! Secondly, that he had never heard of a CC having OVD.

          2. That comment made me think, so went back to the Operation manual for the CC, and also for the Inverter. Yes, the CC definitely has settings for OVD, also UVD. So does the Inverter, which I found is preprogrammed to work between 42V and 62V, thus performing an OVD at 62V. The CC default setting for OVD was 64V and default for Charging Limit was 62V. The CC and Inverter voltages did not seem compatible, so I experimented with lowering the OVD and Charging Limit settings on the CC finally settling on 61.1V for OVD and 60V for charging limit. I also slightly lowered the setting for Absorb from 58.8V to 58.4V.

          3. Now when sun shining brightly, the CC still goes into OVD at around 61V but the inverter does not, which means power supply to the house does not get interrupted.

          4. On the same day as 2 & 3 above, my new digital multimeter arrived. I have been taking measurements at several times;

          (A). At 7.30am before sun over horizon, voltage from CC out was 50.9; at battery terminals 50.9; at Inverter input 50.8.

          (B) at mid morning CC out 55.4; batt terminals 55.4; at inverter 55.3.

          (C) at about 1pm straight after the CC went into OVD, - CC out was 59.1; batt terminals 59.1; at inverter 59.

          At the time the CC went into OVD I was watching the analogue voltage meter. It was a time of lovely bright sun. The needle rose rapidly from 56V to over 60V (the Max reading is 60V), then as the CC went into OVD the needle just as rapidly dropped to 56V. For the next few minutes, while the sun was unobscured, that sequence continued to cycle. Rising from 56 to over 60, OVD occurring, and dropping back to 56. I assume if the sun had continued to shine brightly that process would have continued.

          I have not yet performed voltage tests at night under load, nor been able to perform a system at rest test - still waiting for consistently settled weather when I will disconnect charge and load around midday, leave for four hours before testing.

          Was the initial problem (the inverter going into OVD) caused by incompatible OVD settings on the CC and Inverter? Or, is there a fault with the CC?

          I have no technical training, but it seems odd to me that the CC will go into OVD just because the sun is shining brightly. Being familiar with the regulator on my car, I would have thought that it is the CCs job to regulate incoming voltage from the PV to prevent battery overload. It seems too that this CC (eTracer 60A) is a bit of an odd one out, in that most do not have programmable OVD etc settings installed (according to the advice from our local installer). Also,it seems the CC is going into OVD in response to high voltages coming from PV rather than high voltage in the battery bank.

          Look forward to reading your opinions re the above, and in meantime will carry on with checking with my multi meter when weather conditions permit.

          I checked the Monitor on the CC just now and watched as it performed an OVD. The monitor showed battery voltage as 59.1 and PV voltage as 88.9. I am a bit confused by the PV voltage, as if anything I thought my array was a bit small for my new battery bank, being 16 x 80W panels, thus only 1280W total. Installed by previous owner who told me they are wired to produce 48V. So do not understand how they can output nearly 90V?

          Another thing about the CC concerns me. Only twice, in just over two months it has been installed, have I seen it reach Float. The CC is programmed to Absorb charge for two hours, then I assume it should go to Float?

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          • #20
            May be the CC is triggered by maximum input voltage instead the output voltage. what is the maximum input voltage for this CC? and what is the VOC on these panels?

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            • #21
              Originally posted by Sub View Post
              I have no technical training, but it seems odd to me that the CC will go into OVD just because the sun is shining brightly. Being familiar with the regulator on my car, I would have thought that it is the CCs job to regulate incoming voltage from the PV to prevent battery overload. It seems too that this CC (eTracer 60A) is a bit of an odd one out, in that most do not have programmable OVD etc settings installed (according to the advice from our local installer). Also,it seems the CC is going into OVD in response to high voltages coming from PV rather than high voltage in the battery bank.
              There are two important characteristic voltages associated with a panel:
              1. The open circuit voltage, Voc. This will be more or less independent of the amount of light shining on the panel and will basically depend on the number of cells in series that make up the panel.
              2. The maximum power voltate, Vmp. This will be about 80% of Voc and will also be more or less independent of the amount of sunlight.

              Your CC must be able to safely handle the Voc voltage of your string of panels. The fact that during normal operation the voltage may be lower is not enough to keep the CC safe.
              Your CC will take a varying amount of power from the panels depending on how low the battery is and therefore how much current it can accept.
              If the battery state is such that the CC will use less than the maximum panel power, then an MPPT CC will draw less current and let the panel voltage rise from Vmp toward Voc.

              That is one potential reason for an OVD indication, if it refers to the input from the panels.

              If the OVD indication comes from reading too high a voltage at the battery, then it is an indication that the CC is not regulating the charge current correctly and/or the connection between the CC and the batteries has too high a resistance or an inconsistent resistance (bad connection.)
              SunnyBoy 3000 US, 18 BP Solar 175B panels.

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              • #22
                Voc

                Originally posted by paulcheung View Post
                May be the CC is triggered by maximum input voltage instead the output voltage. what is the maximum input voltage for this CC? and what is the VOC on these panels?
                Maximum solar input voltage, according to the specs in the manual, is 150V dc. My panels Max output is only 1280W, and this CC is capable of handling 3200W.

                Voc , from the spec label on the panels, is 21.6.

                As previously posted, this CC is brand new and replaced an eight year old Xantrex C40 PWM model, which never presented this sort of problem! Beginning to suspect something very wrong with this new CC!

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                • #23
                  Originally posted by inetdog View Post
                  There are two important characteristic voltages associated with a panel:

                  Your CC must be able to safely handle the Voc voltage of your string of panels. The fact that during normal operation the voltage may be lower is not enough to keep the CC safe.
                  Your CC will take a varying amount of power from the panels depending on how low the battery is and therefore how much current it can accept.
                  If the battery state is such that the CC will use less than the maximum panel power, then an MPPT CC will draw less current and let the panel voltage rise from Vmp toward Voc.

                  That is one potential reason for an OVD indication, if it refers to the input from the panels.

                  If the OVD indication comes from reading too high a voltage at the battery, then it is an indication that the CC is not regulating the charge current correctly and/or the connection between the CC and the batteries has too high a resistance or an inconsistent resistance (bad connection.)
                  Panel Voc is 21.6. and maximum output for the 16 x 80w panels is only 1280w. Thus all within spec of the CC - it's specs say Max solar input voltage 150V and max input power 3200w. Thus if the CC is going into OVD because of PV input, then clearly there is a problem with the CC, not the panels, which worked perfectly for over eight years when connected to the old CC - a Xantrex C40 PWM.

                  Nice and sunny today so around noon will connect my DVM to check battery voltage when the CC goes into an OVD. I understand from your advice that if battery voltage increases to the OVD level then the CC is not regulating properly?

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                  • #24
                    Originally posted by Sub View Post
                    Panel Voc is 21.6. and maximum output for the 16 x 80w panels is only 1280w. Thus all within spec of the CC - it's specs say Max solar input voltage 150V and max input power 3200w. Thus if the CC is going into OVD because of PV input, then clearly there is a problem with the CC, not the panels, which worked perfectly for over eight years when connected to the old CC - a Xantrex C40 PWM.

                    Nice and sunny today so around noon will connect my DVM to check battery voltage when the CC goes into an OVD. I understand from your advice that if battery voltage increases to the OVD level then the CC is not regulating properly?
                    It does not matter if the controller is shutting down from input or output over voltage trips. If the panel input Voc is below the specified maximum (Roughly 120 volts or less from the panels to a 150 volt controller) for the controller, or if the controller output voltage exceeds battery voltage, then there is no question the controller is faulty as everything is working within specified working limits. That is unless you have a wiring, or configuration problem.

                    Now with said with 16 x 80 watt panels there is a good probability of wiring problems on the input, but no input wiring problem should cause the controller to over voltage the batteries, unless the controller fails and connect the controller directly to the panels which is a common Failure Mode when the FET shorts out that connect input to output. This is one reason why we use over current protection.
                    MSEE, PE

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                    • #25
                      Originally posted by Sub View Post
                      Maximum solar input voltage, according to the specs in the manual, is 150V dc. My panels Max output is only 1280W, and this CC is capable of handling 3200W.

                      Voc , from the spec label on the panels, is 21.6.

                      As previously posted, this CC is brand new and replaced an eight year old Xantrex C40 PWM model, which never presented this sort of problem! Beginning to suspect something very wrong with this new CC!
                      How are these panels wired? in series or parallel? how many in one series if in series?

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                      • #26
                        Originally posted by paulcheung View Post
                        How are these panels wired? in series or parallel? how many in one series if in series?
                        Sorry to be such a chump, but I really do not know. They were installed over eight years ago by a previous owner of our home. I can from experience now identify whether a string of batteries are wired in series or parallel or both, but I have stood under the PV array trying to work it out, and just can't. All I know is that the previous owner said they were wired to produce 48V!

                        As to an update on the problem, see my reply to another post.

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                        • #27
                          It looks like the CC is not regulating properly

                          Originally posted by inetdog View Post
                          There are two important characteristic voltages associated with a panel:

                          If the OVD indication comes from reading too high a voltage at the battery, then it is an indication that the CC is not regulating the charge current correctly and/or the connection between the CC and the batteries has too high a resistance or an inconsistent resistance (bad connection.)
                          1. At 10.30am today the CC started going into OVD. I stood in front of the CC and watched the Batt Voltage readout on the CC monitor. Voltage climbed quickly to 61.1V which triggered OVD. Voltage dropped back to 54.1 and the CC powered up again, and this seesaw effect keep happening virtually 30 seconds apart.

                          2. I then checked voltage with my digital meter. Connected to batt + & - the meter read exactly the same voltages as on the CC monitor. A regular swing every 30 seconds or so up to 61.1V, triggering OVD, back to 54.1V when the CC turned on again.

                          3. I repeated 2 above with my meter probes at the CC output terminals, with exactly the same result. Which I think should prove that the problem is not resistance in the cable from CC to battery.

                          4. At 10.45am I disconnected CC from Charge and loads. Immediately on disconnect battery voltage read 53.2V.

                          5. At 3.30pm I checked batt voltage again - 52.3V.

                          6. At 4.50pm I did my final checks before reconnecting charge and loads.

                          (a) battery voltage 52.3 from + @ string 1 to - @ string 2.
                          (b) Voltage at string 1 = 52.3
                          (c) String 2 = 52.3
                          (d) I then checked voltage at each individual battery, eight batteries in total -

                          Batteries 1 & 2 = 13.06
                          3 = 13.12
                          4 = 13.11
                          5, 6 & 8 =13.09
                          7 = 13.08

                          I am reassured by the individual battery readings, as I understand since they are all very close to having the same voltage, that means I do not have a "bad battery"? I have been told that a 12V AGM battery is fully charged at 12.9V, thus 51.6V = 100% SOC for a 48V bank. It looks like everything is slightly overcharged. Is that ok?

                          I believe I can now safely assume that the CC is in fact not regulating properly? Looks like time for a warranty claim!

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                          • #28
                            Originally posted by Sunking View Post
                            It does not matter if the controller is shutting down from input or output over voltage trips. If the panel input Voc is below the specified maximum (Roughly 120 volts or less from the panels to a 150 volt controller) for the controller, or if the controller output voltage exceeds battery voltage, then there is no question the controller is faulty as everything is working within specified working limits.
                            Thanks for that Sunking, confirms my thinking - see my other post today in which I detail tests with my DVM.

                            I have found this site and the expertise here very helpful.

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                            • #29
                              Originally posted by Sub View Post
                              It consisted of 16x80W PV panels,
                              <snip>
                              New controller is an eTracer 60amp MPPT controller.
                              Originally posted by Sub View Post
                              Maximum solar input voltage, according to the specs in the manual, is 150V dc. My panels Max output is only 1280W, and this CC is capable of handling 3200W.

                              Voc , from the spec label on the panels, is 21.6.
                              Originally posted by Sub View Post
                              Originally posted by paulcheung View Post
                              How are these panels wired? in series or parallel? how many in one series if in series?
                              I really do not know. <snip> I have stood under the PV array trying to work it out, and just can't. All I know is that the previous owner said they were wired to produce 48V!
                              Your panels are the so-called "true" 12 volt panels (as opposed to "grid-tie" panels). They are configured as four parallel strings, with each string being four panels in series.

                              this is how it should be wired:
                              A cable from each of the four strings runs to a combiner box. The combiner box will have a fuse or circuit breaker for each string. Inside the combiner box, the four strings will be combined, in other words: they will be made parallel. Then a single cable carries the combined current to the charge controller.

                              Your string Voc = 86.4, well within your controller's limits.

                              So now I think I know what's wrong with your system.
                              disclaimer: I'm not familiar with your eTracer controller

                              I believe that your string voltage is too close to your charging voltage. Generally, MPPT controllers need more headroom than PWM controllers. When higher voltage grid-tie panels became so much cheaper than "true" 12 volt panels, it became necessary to use MPPT controllers to reduce the string voltage down to charging voltage. The MPPT controller also "sweeps" up and down the string voltage looking for the voltage with the maximum power. If the string voltage is too close to the charging voltage, the MPPT controller doesn't have enough voltage to sweep through.

                              Quite a few folks with true 12 volt panels have been disappointed by switching to MPPT without reconfiguring their arrays.

                              I predict that the solution for you is to reconfigure your array... three parallel strings, with each string being five panels in series. That will raise the string voltage enough for the controller to function. The Voc at cold temperatures will still be under the controller's limit. You will have one unused panel.

                              --mapmaker
                              ob 3524, FM60, ePanel, 4 L16, 4 x 235 watt panels

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                              • #30
                                Sub quick question for you, actually 3 questions, I am playing a hunch. What are the voltages set for:

                                Bulk = ?
                                Absorb = ?
                                Float = ?

                                You say you have have AGM batteries correct? Make and model number please. Generic voltage set points for AGM assuming normal room temps are:

                                Bulk = 55.8
                                Absorb = 57.6
                                Float 54

                                There is no EQ for AGM so it should be disabled. At no time should your batteries ever see anything more than 57.6 volts from the controller.
                                MSEE, PE

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