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  • Battery issues, need help troubleshooting

    I have 8 x 200 w panels in two strings (4 panels) each connected to an EPSolar ETracer 30 amp controller, fused and each connected to one string of 4 x L16 - 6 volt batteries wired to 24 volts. I run a 2 kw inverter but use little power except for a small refrigerator and a few lights.
    I failed to do my regular battery and system maintenance for a variety of reasons. When I recently did my inspection following several days of bleak November weather I discovered my batteries seriously depleted (ranging sg 1150 and lower) I further discovered when I circulated my batteries that I had two bad solder joints(one between batteries and the other from my disconnect switch from one of the controllers to one of the battery strings) which obviously led to my problems.
    I set my charger to 40 amps and charged for approx. 6 hours in an attempt to bring my batteries up since we still did not have any sun, but, the ammeter shows only 20 amps charge all the time that I was charging.
    I realize that my expectations are great in consideration to the fact that I have only actually charged the batteries for a short time. That is not my main concern. Have I ruined my batteries? Is that why they fail to charge at a rate higher than 20 amps? Any suggestions?

    ---Mod Note: I have moved this question to its own thread rather than clutter up the sticky thread.
    Last edited by inetdog; 11-18-2015, 07:59 PM.

  • #2
    Originally posted by Dougahole View Post
    I further discovered when I circulated my batteries that I had two bad solder joints(one between batteries and the other from my disconnect switch from one of the controllers to one of the battery strings) which obviously led to my problems.
    Beg your pardon, but WTF do you mean solder joints?

    Not only is that a code violation, but just asking for failure and extremely unsafe. Sorry, I cannot help you.
    Last edited by inetdog; 11-18-2015, 09:44 PM. Reason: fixed spelling of solder
    MSEE, PE

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    • #3
      Well, given that those batteries have a C20 around 370AH, the charging rate of 40A would be within the C/12 to C/8 range. I do not see any obvious reason that a grid powered 40A charger should not be delivering that 40A charge current to your batteries.
      But, that said, a lot of automotive chargers, when connected to a good battery that is at a low State Of Charge (SOC), will just not deliver their rated current.

      Some of the things to look at:
      1. What is the batter terminal voltage (measured with a good voltmeter, one on the charger) while charging? With the charger disconnected?
      2. It is not unreasonable that the internal resistance of the batteries is high and that may be limiting the charge current. Also consider that if they are 50% sulfated the real capacity would be ~185AH instead of 370AH and 20A would actually be a suitable charging current.
      3. Measure the voltage at the battery terminals as well as across the string of two. Is the charger connected directly to the battery posts or to bus bar? If you see a voltage drop of .05V or more across the inter-battery cable you may need to do some more work. Just how did you make all of your cables? As Sunking stated, soldering is not a good idea and should never be used except AFTER making a sound pressure crimp or bolt connection. The NEC does not allow you to depend on the solder for the mechanical integrity of the joint.

      You need to keep an eye on the SG at least once per day and see how it is changing. At some point the SG may be well below that for 100% SOC and the current from the charger has gotten much smaller. At that point you may need to switch to your solar CC or other charger that can be adjusted temporarily to a higher Absorb voltage. You will be doing something close to an equalization charge to try to recover your battery. Keep an eye on the battery temp so that it does not go too high and keep the electrolyte level above the plates at all times. You may see that the SG plateaus out below 100% SOC. In that case those batteries may be beyond redemption.
      You can search for some of the desperation battery recovery discussion posts by PNJunction for extreme measures.
      SunnyBoy 3000 US, 18 BP Solar 175B panels.

      Comment


      • #4
        Originally posted by Dougahole View Post
        I have 8 x 200 w panels in two strings (4 panels) each connected to an EPSolar ETracer 30 amp controller, fused and each connected to one string of 4 x L16 - 6 volt batteries wired to 24 volts. I run a 2 kw inverter but use little power except for a small refrigerator and a few lights.
        I failed to do my regular battery and system maintenance for a variety of reasons. When I recently did my inspection following several days of bleak November weather I discovered my batteries seriously depleted (ranging sg 1150 and lower) I further discovered when I circulated my batteries that I had two bad solder joints(one between batteries and the other from my disconnect switch from one of the controllers to one of the battery strings) which obviously led to my problems.
        I set my charger to 40 amps and charged for approx. 6 hours in an attempt to bring my batteries up since we still did not have any sun, but, the ammeter shows only 20 amps charge all the time that I was charging.
        I realize that my expectations are great in consideration to the fact that I have only actually charged the batteries for a short time. That is not my main concern. Have I ruined my batteries? Is that why they fail to charge at a rate higher than 20 amps? Any suggestions?

        ---Mod Note: I have moved this question to its own thread rather than clutter up the sticky thread.
        You mentioned 2 strings of panels, cc and battery. Do you have the same charging issue on the other battery set?

        Also how were the batteries wired in series and why did you have solder joints?

        Comment


        • #5
          Battery issues

          - 2 strings, 4 x 200 panels to each string, 1 cc per string, 4 batteries in series per and then in parallel
          - second string not so affected but somewhat lowered due to demand
          - local battery supply uses crimp and solder. I visited the store today and confirmed this. I also asked about code but they did not appear to believe that they were not meeting code, this is Ontario so I do not know the code. None the less, I will do things differently.

          Q. Does anyone have a web supplier for battery accessories that ships into Canada. I live over 100 miles from Toronto and do not relish driving into the city ln order to shop

          Comment


          • #6
            Originally posted by Dougahole View Post
            - 2 strings, 4 x 200 panels to each string, 1 cc per string, 4 batteries in series per and then in parallel
            - second string not so affected but somewhat lowered due to demand
            - local battery supply uses crimp and solder. I visited the store today and confirmed this. I also asked about code but they did not appear to believe that they were not meeting code, this is Ontario so I do not know the code. None the less, I will do things differently.

            Q. Does anyone have a web supplier for battery accessories that ships into Canada. I live over 100 miles from Toronto and do not relish driving into the city ln order to shop
            Ok. To confirm you have 8 x 200w panels, 2 x 30amp tracer CC, and 8 x 6v batteries total.

            There are two sets of (4 x 200 watt panels) that each set is wired to it's own 30amp CC. But both of the CC's are then wired to the 8 x 6v 24volt (4s2p) battery system.

            Let me know if I got that circuit wrong.

            Comment


            • #7
              Originally posted by SunEagle View Post
              Ok. To confirm you have 8 x 200w panels, 2 x 30amp tracer CC, and 8 x 6v batteries total.

              There are two sets of (4 x 200 watt panels) that each set is wired to it's own 30amp CC. But both of the CC's are then wired to the 8 x 6v 24volt (4s2p) battery system.

              Let me know if I got that circuit wrong.
              Just to confirm. Each set of 4 batteries is connected to a cc and then the batteries are wired in parallel

              Comment


              • #8
                Originally posted by Dougahole View Post
                Just to confirm. Each set of 4 batteries is connected to a cc and then the batteries are wired in parallel
                But in reality if those 8 batteries are wired in parallel and each set has a CC wire to it then you technically have two different sets of panels & cc trying to charge the same set of batteries.

                My direction is trying to figure why your "solder connections" melted. It may be possible that with two different charging systems connected to the same battery system resulted in some of those wire connections being over loaded.

                Comment


                • #9
                  Battery issues

                  Originally posted by SunEagle View Post
                  But in reality if those 8 batteries are wired in parallel and each set has a CC wire to it then you technically have two different sets of panels & cc trying to charge the same set of batteries.

                  My direction is trying to figure why your "solder connections" melted. It may be possible that with two different charging systems connected to the same battery system resulted in some of those wire connections being over loaded.
                  Possibly I did not fully explain myself. It is like having two systems running next to each other each system has 4 panels, cc, and 4 batteries in series for 24 volts. The batteries are finally connected in parallel + to + and - to - at the opposite end of each string. A Photo of the installation can be seen on page 154 of the AEE Catalogue

                  Comment


                  • #10
                    Originally posted by Dougahole View Post
                    Possibly I did not fully explain myself. It is like having two systems running next to each other each system has 4 panels, cc, and 4 batteries in series for 24 volts. The batteries are finally connected in parallel + to + and - to - at the opposite end of each string. A Photo of the installation can be seen on page 154 of the AEE Catalogue
                    Anything that you do to connect the two "separate systems" in parallel will also put the two strings of batteries and the two CCs in parallel too.
                    If you are going to parallel the strings of batteries you need to carefully match their SOC and therefore terminal voltage before you switch them into parallel. Otherwise the short term balancing currents could damage both the wiring and the batteries themselves.
                    Or are you using massive isolation diodes between the battery strings and the load bus?
                    SunnyBoy 3000 US, 18 BP Solar 175B panels.

                    Comment


                    • #11
                      Originally posted by inetdog View Post
                      Anything that you do to connect the two "separate systems" in parallel will also put the two strings of batteries and the two CCs in parallel too.
                      If you are going to parallel the strings of batteries you need to carefully match their SOC and therefore terminal voltage before you switch them into parallel. Otherwise the short term balancing currents could damage both the wiring and the batteries themselves.
                      Or are you using massive isolation diodes between the battery strings and the load bus?
                      Thanks for your input. Believe me it is much appreciated. I am ignorant enough that I did not know that diodes were required. I can say however that my monitoring of the cc's up until recently has showed the soc always within about 1-2% (accuracy not determined)
                      Other than diodes are there any other suggestions to reconcile the issue of the banks being out of balance? If diodes are the only realistic option can you suggest?

                      Comment


                      • #12
                        Originally posted by Dougahole View Post
                        Thanks for your input. Believe me it is much appreciated. I am ignorant enough that I did not know that diodes were required. I can say however that my monitoring of the cc's up until recently has showed the soc always within about 1-2% (accuracy not determined)
                        Other than diodes are there any other suggestions to reconcile the issue of the banks being out of balance? If diodes are the only realistic option can you suggest?
                        I am not seriously suggesting diodes, I am just trying to indicate to you that rather than two "separate" systems in parallel what you have could better be described as a single battery bank composed of two series strings that have been put in parallel and then two CCs which are operating in parallel connect to that single large battery bank.
                        Any variations that you see in string voltages are there entirely because of differing resistances in the cables from the two strings.

                        Take a look at http://smartgauge.co.uk/batt_con.html for an introduction to what happens when you put batteries (or strings of batteries) in parallel.
                        Everywhere on that page that it shows single batteries you can substitute identical strings of batteries in their place. So your two string setup will be the equivalent of the two battery setup shown.
                        SunnyBoy 3000 US, 18 BP Solar 175B panels.

                        Comment


                        • #13
                          OK first you have two solar panels systems charging common battery improperly wired and terminated. Solder joints or any poor connection will melt and or burn when too much current flows. The dead give away is if the damage is centered around a connection point,is proof positive of a poor connection. Regardless of what you might think or have been told, solder connections generally have higher resistance than a irreversible compression connection. It takes great skill to solder and attention to detail to be done right and safely. Secondly soldered connections have very poor mechanical strength. NEC codes does permit solder to be used, but is required to be mechanically reinforced. in other words a backup. It is an antiquated technique used in old Knob & Tube wiring found in extremely old homes. Soldering is an art and requires a lot of experience to do correctly. The only electricians who use it are old farts that preserve historic buildings under scrutiny requiring special permission to use in some states. In the USA is limited to a few historic buildings in New England states. Otherwise not permitted. All that remains is Grand Fathered. Any additions or new construction must otherwise follow current code practices in both USA and Canuck.

                          From what I can tell from your line of questions and inexperience I will not be able to help you as what you describe is an accident waiting to happen and I want no part of it. FWIW whoever at the store told you they know of no issues with solder joints, should be the first ones your lawyers go after before going after the folks here and the Forum owners trying to help you. Sory but you do not even know the right questions to ask.

                          Knob and Tube

                          maxresdefault.jpg
                          MSEE, PE

                          Comment


                          • #14
                            Originally posted by Dougahole View Post
                            Q. Does anyone have a web supplier for battery accessories that ships into Canada. I live over 100 miles from Toronto and do not relish driving into the city ln order to shop
                            My personal fav is Princess Auto, all canadian eh, lots of interesting diy stuff in store and amazing sale prices - they ship online but their online search is not the greatest to find stuff with. Then there is amazon.ca. Then local can tire...

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