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  • #16
    Apologies for jumping in here. My battery setup is doing the same thing. You say it won't harm the batteries to have the charge controller pushing 14.4V on a full battery. Mine is actually making bubbling/fizzing noises while it's happening, and one is about 0.5V higher than the other. It's hard to believe a full battery won't be harmed when 14.4V / 2.2A is being pushed into it for 2 hours, but that's only because I don't know what I'm doing here. Can you explain why it's OK to have such a high voltage/amperage pushed thru a full battery? Thank you.

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    • #17
      In the first place, nobody has determined that the battery is "full". This can only be determined by measuring the specific gravity of the electrolyte solution. To properly fully charge a flooded lead acid battery you need to have an absorb phase as long as nessecary to get the s.g. up to the manufacturers recommendation. That is 1.260-1.277 for most large format FLA batteries. The manufacturers recommended voltage for my Rolls Surette L-16 428 a.h. battery is 28.8 -29.4 volts with an equalization voltage of 30.00 to 32.00 volts (24 volt set of 4 ea. 6 volt 428 a.h. batteries) to achieve recommend s.g. of 1.260. Different batteries have different specifications, it is very important to get your manufacturers specifications and do get a hydrometer to log the specific gravity of each cell. Voltage readings are only an indicator of state of charge. The hydrometer is the instrument that tells the true state of charge. All electronic monitors only count amps and volts in and out, they can only guess at true state of charge. They need to be calibrated as to the efficiency of the battery

      The bulk state only gets the battery to 90% s.o.c., it's the job of the absorb stage to get that top 10% in and gassing and bubbling is normal at this stage. If it takes 4 hours to get all cells equal then it will not hurt the battery. Do monitor the battery voltage and temperature and keep it below 90 degrees Fahrenheit , and make sure that all cells have sufficient electrolyte.

      One of the fail modes of such large format wet cells is acid stratifaction, the acid is stronger at the bottom than at the top, especially when systematically undercharged. This leads to the stronger acid at the bottom of the cells eating away the grids and plates. The bubbling remixes the acid to a uniform gravity throughout the cell.

      And that's it on this class battery tech 101
      Last edited by Tecnodave; 06-12-2019, 08:23 PM.

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      • #18
        During Absorb, my battery room sounds like a pit of snakes hissing. Perfectly normal
        Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
        || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
        || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

        solar: http://tinyurl.com/LMR-Solar
        gen: http://tinyurl.com/LMR-Lister

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        • #19
          Thanks Dave. Not sure why you're talking about 28-32 volts, etc. Nobody here is talking about a system of that voltage.

          You mention that fizzing/hissing is completely fine, but everything that I've read suggests that fizzing/hissing should never happen on AGM batteries, and when it does, you're overcharging the battery and introducing more current than the battery can accept chemically. You're literally boiling off the electrolyte and will damage the useful life of the battery. You saying that this hissing and bubbling is "normal" (and that it's battery tech 101) goes against everything I've read so far on AGM batteries.

          Not trying to push back here, but unsure how to reconcile these two opinions, when to me, boiling/hissing on an AGM battery does seem to mean you're creating gas by destroying electrolyte...that can't be good.

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          • #20
            Dave is referring to flooded lead acid batteries and everything he is telling you is correct. Apparently you haven't made clear you are referring to AGM batteries. Fact is AGM batteries can handle double the current that flooded batteries can, the thing they cant handle is excessively high VOLTAGE.
            2.2kw Suntech mono, Classic 200, NEW Trace SW4024

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            • #21
              Originally posted by littleharbor View Post
              Dave is referring to flooded lead acid batteries and everything he is telling you is correct. Apparently you haven't made clear you are referring to AGM batteries. Fact is AGM batteries can handle double the current that flooded batteries can, the thing they cant handle is excessively high VOLTAGE.
              With all due respect, this entire thread has been about AGM batteries, from the very first post.

              Again, this doesn't address the concern that any bubbling or hissing you hear is electrolyte boiling off and creating gas, which is irreversible damage (even if only a little) from everything I've read online. Is what I've read all incorrect that AGM batteries bubbling/hissing is a bad thing?

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              • #22
                Originally posted by adrewnaline View Post

                With all due respect, this entire thread has been about AGM batteries, from the very first post.

                Again, this doesn't address the concern that any bubbling or hissing you hear is electrolyte boiling off and creating gas, which is irreversible damage (even if only a little) from everything I've read online. Is what I've read all incorrect that AGM batteries bubbling/hissing is a bad thing?
                OK, lots of "out of scope" batteries have been brought up and I lost focus on the OP's equipment.

                [B]Correct, AGM batteries are very sensitive to over-charge and damage from it. [/B]

                The owners responsibility, if they don't contract a vendor to manage the system, is to become enough of a Technician to understand their proposed setup, design it, and maintain it.
                I can chime in regarding gear I'm acquainted with, and if someone else has un-related gear (like flooded batteries)[B] they are to refrain[/B] from topic drift and [B]not [/B]bring up their personal configuration if it's not related to the OP's situation. I'd responded to another setup, not Ben's.

                I (and other moderators) cannot possibly learn and provide advice on the plethora of gear that exists and is being invented. We can only comment on what we understand and not speculate on what might work.

                If you plan a system around z-45 Helium batteries and Tracer -9Z controllers, make sure the gear is compatible BEFORE you buy it. There will be many times when full charge is not achieved with solar only and a secondary charge source (generator) brought into play to prevent blackout or battery damage.

                Chronic Undercharge is a common neophyte method of ruining battery banks. Not understanding how batteries charge and the charge cycle sequence, leads to more batteries murdered.

                I don't have your battery manual or your charger manual. My first step is to say "Download the manuals and configure things properly". Use the right gauge wire (tables and charts on the internet) and fuses.
                Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
                || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
                || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

                solar: http://tinyurl.com/LMR-Solar
                gen: http://tinyurl.com/LMR-Lister

                Comment


                • #23
                  AGM, or absorbed glass matt batteries are generally 98% saturated with electrolyte. They are considered "Non Spillable" because of the less than 100% saturation. They are also referred to as VRLA, or valve regulated lead acid which will vent only upon being overcharged. So, yes they will be irreversibly affected by overcharging and venting gas, which otherwise will be recombined back into the electrolyte.
                  2.2kw Suntech mono, Classic 200, NEW Trace SW4024

                  Comment


                  • #24
                    Thank you for confirming. I didn't see anybody talking about anything other than AGM, so I don't understand the "out of scope" comment, but do appreciate the insight. I'll be sure to keep my charging voltage per cell to the manufacturer's recommended values, and if any gas is expelled at those values, lower the input voltage and diagnose. Have a good one.

                    Comment


                    • #25
                      Adrenaline,

                      My reading of the thread seems to focus on the controller not doing as it should. I read hundreds of threads here and at other forums every week. I work in the electrical industry and am paid there. I share what I know here and other forums not only on solar but other highly technical issues as well. I did look back and see where the OP did mention AGM in the original post but nowhere do I see you adequately describing your system at all . That leaves me to guess just what your issues are. You did not define enough for me to work with but I offered help anyway. If you truly want help with issues you need to fully define the issue as you understand it. That will help others define the real problem for you.

                      so my bad, I do not go back and read every thread from the start, I think every one who does post frequently does the same.

                      On AGM batteries, they need a more controlled charge than FLA and gassing is not normal for these batteries. They still require a "set time" at absorb to fully charge. Unfortunately with AGM you cannot measure specific gravity and with most you cannot measure cell voltage individually. Now you are left with guesses as to the state of charge. The worst indicator is the "crude columb counter" built into cheep Chinese controllers such as the EP Solar Tracers. Totally useless as this is a guess of the worst kind. Unfortunately people regard this as fact.....Much better is the better quality columb counters such as the Victron Smart monitor such as the OP stated that he uses, or the Bogart Engineering Tri-Metric monitor, these actually have a shunt at the battery which can much more accurately can calculate battery efficiency and are much better for evaluation of the situation.

                      So specially to your situation, you state that your batteries are not equal in voltage, that is because you have neglected battery maintaince and have either undercharged consistently of overcharged the batteries. Your best tool here is the infrared heat gun, While charging this set use the infrared heat gun to check the temperatures on the sides near the top of each cell and log the temperature several times , you need to look for a hot spot which will tell you that this is the failing cell.
                      There is no recovery process that will fix a failed cell but improvements can be made by limiting the voltage to the Manufacturers specifications of that battery, that exact type, recommended charge profile. Limit the current to not over 5% or so of stated capacity. If in doing this there is one spot that continues to be hotter that anywhere else you have a failed battery. Do not replace one battery with a new one, you must change them as an exactly matched pair if you want good service.

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                      • #26
                        Originally posted by Tecnodave View Post
                        Adrenaline,

                        My reading of the thread seems to focus on the controller not doing as it should. I read hundreds of threads here and at other forums every week. I work in the electrical industry and am paid there. I share what I know here and other forums not only on solar but other highly technical issues as well.
                        Nobody is doubting you're an electrical god and an absolute unquestionable authority on all things solar and battery related. Don't worry. You're the alpha dog here. I'm just a nobody, "junior poster" begging for help and kissing your toes for all you've so graciously given me. You are a high ranking official of this forum, and I have no place questioning you. Please, my lord, have mercy on me for not explicitly stating that I also had AGM batteries in my reply.

                        Originally posted by Tecnodave View Post
                        So specially to your situation, you state that your batteries are not equal in voltage, that is because you have neglected battery maintaince[sic] and have either undercharged consistently of overcharged the batteries.
                        That's quite the assumption, seeing how these batteries were just purchased as a pair, hooked up, and immediately exhibited this behavior. Again, I'm not questioning your holy authority, but claiming this is because I "neglected battery maintaince[sic]" is hard to believe as I haven't had them service for more than 20 minutes at this charge rate.

                        Originally posted by Tecnodave View Post
                        Do not replace one battery with a new one, you must change them as an exactly matched pair if you want good service.
                        Fantastic advise. Thank you so much. I'll likely be doing that, as this matched pair has 0.5V difference in voltage when charging, indicating a difference in internal resistance that I'm uncomfortable with and/or a bad cell.

                        Thanks again for all of your help. This forum doesn't deserve all that you do our of the graciousness of your heart.

                        Comment


                        • #27
                          Adrewnaline,


                          You still have not stated just what batteries that you have, how long that you have had them etc. I am forced to guess that you had them in service for a while, if that is not the case them you need to proceed with the facts, they are in front of you, not visible to me. If indeed you purchased two new matched pair of batteries and they are not equal in voltage then you do have an issue that you need to deal with. If these batteries are in parallel then there is something very wrong here. If these are 6 volt AGM batteries in series they are not balanced. In any case the only appropriate diagnostic step is to charge them one at a time until at full charge. Use a charger capable of being programmed to the manufacturers stated charge profile for that exact battery.

                          I am not an all knowing expert on the subject, just another person who shares what they know freely. There are many people with knowledge on these forums, some are willing to share. I have learned much here and at other forums. I can tell you that I did solar systems for high end mountaintop radio communications way back in the late '60 thru the '80's until I bailed from communications due to extreme EMI/RFI environment that I worked in.
                          I continue to work in the electrical power fields, not solar. My work is exclusively with PoCo supplied power, mostly agricultural, but industrial as well.
                          I live off grid and have been solar powered exclusively for over 25 years now

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                          • #28
                            Originally posted by Tecnodave View Post
                            Adrewnaline,


                            You still have not stated just what batteries that you have, how long that you have had them etc.
                            Please see this thread: https://www.solarpaneltalk.com/forum...while-charging

                            Two 6V VMAX-225Ah Batteries, wired in series. As stated above, freshly purchased as a pair from the top ebay listing when you search for them. More details in the thread above.

                            At resting stage (after 12 hours resting), they have the same voltage. When charging at 14.4 volts, they have different voltages, with a delta of 0.5V. When charging at lower voltages, the delta is less.

                            Unsure how charging independently will make it so they both charge at the same voltage when wired in series, but I'll try it. Though I already asked if I can return them from the eBay listing.

                            Do you know of a charger off hand that may work with these 6V AGM batteries? I'm searching but am coming up short. All I have at home is a standard 6V charger with a deep-cycle setting.

                            Thanks.

                            Comment


                            • #29
                              Adrewnaline,

                              I have just reread your other thread, I had read it before but I did not connect the two threads. You probably bought a bad battery. Personally I buy my batteries from battery wholesalers, not at Costco, Kmart or FleaBay due to the expertise found at battery dealers. They know how to store batteries , charge them, etc. If you do not have a decent charger that can be programmed for the current and voltage limits suitable for this job then do just exchange them. It could be the case that one has sit for a long time and needs to be charged slowly up to full charge. I use only fully programmable chargers, not generic one size fits all automobile chargers.

                              You are correct in assuming that half a volt difference is not normal, there should be very little variation in voltage in a series stack. The fact that you state the voltage raises quickly on only one is not a good sign.

                              On your suggestion that you should exchange them for two 12 volt batteries in parallel that will be far more troublesome than a series string as especially AGM batteries do not balance well in parallel due to the very low internal resistance of such batteries.

                              I gave up on the EP Solar Tracers some time ago and do not remember if they do have user adjustable current settings or not. If they do then set the current very low at maybe 4-5 amps or so and the voltage at the manufacturers recommendations, some are 14.3 others are 14.4, and do a long slow charge.

                              Personally I use MidNite Classic and Kid controllers which are fully programmable voltage and current. I think only the very best controllers have that capability, the MMMOS group...MidNite,MagnaSine, Morningstar's,Outback, and Schnieder maybe a few others, but that won't be found on Chinese generic chargers.

                              In experimental work I use a DC to DC charger, the Junsi iCharger i208B. This is a very versatile charger that is directed at the model airplane crowd, It can be programmed to any charge profile needed. It is really for lithium types but does have built in profiles for LA, NiCad, NiMh, LILO, LiPo, LiFePO4, one cell to many within its rated specs. It is fully programmable as to max voltage, current and does have a lithium balancer built in for up to 8 cells. Too much information but to give you an idea of how I approach the issue.

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                              • #30
                                Originally posted by littleharbor View Post
                                Dave is referring to flooded lead acid batteries and everything he is telling you is correct. Apparently you haven't made clear you are referring to AGM batteries. Fact is AGM batteries can handle double the current that flooded batteries can, the thing they cant handle is excessively high VOLTAGE.
                                Post # 1: " to give power to my system's 230AH Trojan 8D (AGM)."
                                SunnyBoy 3000 US, 18 BP Solar 175B panels.

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