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eTracer 60A charge controller and AGM batteries

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  • eTracer 60A charge controller and AGM batteries

    Replaced my old batteries and charge controller about six weeks ago.
    The new batteries are 12V AGM 290 Ah, wired in two banks of four. Each bank is wired in series and connected to each other in parallel. Thus 580Ah in total. I know parallel connection is not recommended, but it was the only economical way to get a battery bank delivering over 500Ahrs
    The Tracer controller is programmed to do an equalisation charge on the 28th of each month. I have learnt that generally it is not a good idea to do an equalisation charge on sealed batteries, but that parameter cannot be removed. The setting for the charge is at the default parameter of 58.4V, which is only .8V higher than the default boost charge rate. The time for the charge again is at default setting of 120 minutes. The seller of the controller (and batteries) suggested altering the voltage setting and the time setting for the equalising mode. Voltage has optional settings between 56.8 and 60.8, and time has the options of 0 to 180 minutes.
    Question 1 - should I alter the settings as suggested? If so to what?
    Question 2 - as programmed, the charge controller entered equalising mode on the 28th of June. Four days later it is still stuck in that mode. The guess is, as we have had clouds and heavy rain for most of that time we have not had 58.4V of charging for the required 120 minutes. Is that a fair assumption? Or is the controller faulty?
    Thanks in advance for your help.

  • #2
    Set EQ time to lowest setting like 1 minute.
    MSEE, PE

    Comment


    • #3
      Might have.fixed it!

      Found I could not enter a time value of 1 minute - my attempt to modify time would only allow me to enter 005, and then when I tried to save that value, it entered 60 minutes. Elsewhere in the operation manual it says constant equalisation period is 60 - 180 minutes, so it looks like the smallest value able to be entered is 60.
      After another two days, during which time we had periods of good sun, Charge Mode remained firmly stuck on "Equalize"!! After several emails and a couple of phone calls to the supplier he suggested I alter the battery type setting to GEL, as this controller is meant to then automatically deselect Equalize mode. But it didn't, and today after anxiously watching voltage levels creep up - batt voltage 59, PV voltage 71, and my separate analogue voltage meter, which has a maximum reading of 60V was off the scale. All the while the charge mode remained stubbornly on Equalize!
      I rang the supplier again and I asked if it would be safe to pull the main fuse, and he said to give it a go, but to pull the PV fuse first. Did that and after letting things settle for a few minutes, put the fuses back, and the controller reset itself properly. Batt Type remained on GEL, and the Equalize mode was disabled. I have left all other parameters at default, except Boost charge voltage, which at the suppliers suggestion, I reset to 58.4V.
      So far everything seem to be working ok again, but when I have replaced my broken voltage meter I will individually check each battery voltage in case there is a bad one in the bank.

      Comment


      • #4
        Sub - glad you got it. That etracer (actually an EPsolar) is similar to my own epsolar pwm as far as voltage flexibility goes, so I'm a bit familiar with it.

        Like most of us starting out, we learn the hard way that the controller needs to be attached to the battery first to get its mind together and after that make the panel connection. While my own epsolar does seem to accept changes in programming while connected, I still ensure that when I do make a change, I disconnect the panel and battery, then reconnect battery first, panel last just to ensure that the cc doesn't get confused.

        Amazingly, I do like how they will NOT let you custom program the GEL settings, which has a MAX boost (aka absorb to most of us) at 14.2 - a bit too high for gel for my tastes, but nobody should really be using gel for solar in the first place. What the dealer suggested about going to gel with your agm would result in undercharging them, and in the future, I would take what he says with a grain of salt, as it is clear he does not understand the difference between gel and agm, or figures YOU would never know.

        One thing you can do to "trick" the mandatory 28day eq, is to just set the EQ voltage the same as your boost voltage. The boost, eq, and float are all adjustable in either the AGM/Sealed or Flooded settings, which you can override. First I tell the controller I'm using the SEALED settings, and then go on to customize the voltages. Then do the disconnect/reconnect sequence to make sure it comes back up with all my customized settings.

        What this means is that every 28 days, your agm's will not experience an EQ, but now with the voltages set the same, it will merely do an extended absorb instead. This would actually be very good for the agm.

        What agm's specificallly are you using? The manufacturer should list the proper boost (aka absorb) voltage for a 12v battery. You can then multiply this by 4 to get your setting for the controller. You can be sure that it is NOT 14.2 which is meant for gel, and would result in poor charging for your agm. Shame on that guy.

        Also, are you using the remote temperature probe? Does that controller have an internal ambient temp compensation? If so, you'll want to use that, and being winter where you are, measured terminal voltages will actually rise higher than the settings you made in the controller due to the temperature compensation factor. Amazingly, these controllers allow you to custom program the temp-comp values too! I think the default is something like 0.003v per degree C.

        If you don't have temp comp, one thing you could do is custom program the sealed and flooded to emulate a "winter" and "summer" setting if you meticulously calculate the temperature compensation offset seasonal differences into them, and switch between those saved settings seasonaly. Not the greatest winging it like that, but better than nothing I suppose. Ie, something like +0.003v for winter, and -0.003v for summer - still best to just fork out for the remote temp sensor and let it do it's thing.

        One thing you haven't mentioned is the amount of power you draw daily, and what the size of your array is. It may be possible that if too small, you are in a "deficit charge" scenario and are quickly killing the bank.

        At any rate, AGM's like a at least 8-12 hours or more of float, something we obviously don't have the luxury of doing with solar. One way around this in a cyclic application, is to extend boost/absorb especially if your controller has a fixed timeout during boost, and the bank actually needs more time than that. Instead, it goes to float too soon.

        What you can do here, which I and some others recommend, is to trick the controller once again, and set your float voltage to the same value as the boost voltage to compensate. Now the boost voltage timeout won't matter as it switches to float with the very same voltage as boost and the loss of sun is the master switch to make sure that you don't exceed the manufacturer's limits for spending time in boost/absorb.

        Obviously if you only draw something pitiful from your bank, and it really gets recharged in the first 30 minutes of your solar insolation period, then perhaps think about returning float to a more normal value - which you may hit in your region during the summer with extremely small discharges.

        Comment


        • #5
          Thanks for you advice Pjunction

          The eTracer 60A MPPT controller is made by EPsolar. So is similar to yours.
          On this model I am able to leave Batt Type to GEL, and modify most values (except system voltage, which it automatically detects). So to be fair to the dealer, he did say leaving the Boost (absorb) setting at the default GEL rate of 56.8 was not enough for these batteries, and told me to change it to 58.4V which I have done.
          Float charge remains on the default setting (the same for all three types of batteries) of 55.2, and has optional range of 13.2 - 14.2, and presently remains on the default setting.
          The controller came with the optional remote temperature probe, and it is installed. While we are in the middle of winter we live in the far north and do not get frosts. Around noon when I check, the Device temp usually shows around 18 degrees and batt temp around 11.
          The batteries have only recently been installed. They replaced a bank of Trojan T105s - 16 in two strings of eight giving 48V and 450ahrs c20. Those batteries were installed by previous owner and lasted 8 years and 3 months - could have gone longer I guess but didn't want to risk them dying over winter.
          The new ones are Chinese made - can't find a manufacturer name on them, they are labelled AAChampion, and imported solely by the dealer I bought from. They look very similar to pictures of the UPG batteries I see listed for sale on US websites.
          While I would have preferred using batteries giving over 500ahrs without going to a parallel set up, the cost here in NZ was prohibitive. As an example, simple Trojan L16s retail here for NZ $790 each, Raylite 6V giving 600ahrs are more than $1500 each, and 2V cells are between $500 to sky the limit.
          The AAchampions get rave reviews from members of an NZ Rv club. My 12V 290ah c20 (the amp hours on them are stated on the spec sheet as 325 @ c100 & 250 c10) batts retail here for $679 each, and as my son in law is in business as an electrician, he was able to get them cheaper for me on his account with the dealer! Cost wise it was no contest! They also have a five year warranty (pro rata after one year).
          I did an audit of my power use when we moved here 4 years ago, I was very conservative with my calculation and rounded figures up. It came out to 3630W, which I rounded up to 3800, and that I believe converts to 79 amps which I have rounded up to 80 amps per day. I understand the formula for battery sizing to multiply daily use by 3 = 240 and since we should not exceed 50% depth of discharge I therefore must have at least 480ahrs available. I wanted more than that as we want to add a deep freeze to the mix, and as we now have broadband, we have a modem going probably 10 hours a day since the audit.
          Re my PV array, I do wonder if it is too small. It consists of 16 x 80W panels - installed April 2006 - so only producing 1280W. Is it possible to add more, higher wattage, panels or would I have to scrap them and start again?
          Another question. The eTracer controller has a monitoring display interface, however the dealer says that this will not give me real time information about batt voltage, SOC, amps etc, and wants to sell me a trimetric battery monitor with 100A shunt costing $399. There is an accessory available for the controller which allows me to connect it to my computer, but he says that this will not give me the real time info I need. Is he correct - do I "need" a trimetric battery monitor?

          Comment


          • #6
            Sub can you give me the model and make of the batteries? If I know that I can be a little more detailed.

            A 48 volt AGM range is 56.4 to 58.8 depending on Temperature and Time they can remain on Absorb. Problem is Solar is a really poor source of energy for charging batteries simply because there is not enough hours to go through all 3 stages of charging. Secondly most Solar Controllers perform Absorb cycle on time rather than current cut-off of 1 to 3% C. Mostly because of the fact there are not enough sun hour sin a day to get there unless shallow cycled.

            Assuming you do discharge 20 or more percent in a day here is my best advice. Since you are in a hot Climate, start at Set Bulk = Absorb = 56.4 volts and Float = 52.8 and use Temp Comp.
            MSEE, PE

            Comment


            • #7
              Battery model

              Hi Sunking,
              I cannot find a manufacturers ID on the battery. They are named "AAChampion", and I presume are made for the dealer as they have his logo printed on them. The dealer's product list gives them "Model # C12V325", and gives the following specs -
              325ah C100, 250ah C10, recommended Bulk charge = 58.8V, Absorb charge 58.4V, Float 54.8.
              Dimensions are L 522mm (20.4 inches), W 268mm (10.5 inches), H 220mm (8.6 inches), weight 70kg (155lb).
              As per my previous post, they look very similar to UPG batteries I have seen photos of on US websites.
              Cheers, John
              PS - my average daily usage discharges the batteries between 15 and 20% overnight.

              Comment


              • #8
                Originally posted by Sub View Post
                recommended Bulk charge = 58.8V, Absorb charge 58.4V, Float 54.8.
                Are you certain that is correct? What you are showing is Bulk voltage is greater than Absorb or baskasswards. That would mean you would have to discharge the battery to switch to Absorb. Does not make any logical sense. Anyway disregard the voltages I recommended. But what really bugs me is Bulk greater than Absorb, and the voltages are a little higher than I would expect. Otherwise set Bulk = Absorb = 58.8 and Float = 54.8
                MSEE, PE

                Comment


                • #9
                  Voltages

                  Hi again Sunking
                  I have rechecked those voltages, and they are as I have quoted - except for the Absorb figure. The battery spec sheet does not give a value for that stage. It simply says "Absorption time of one hour for every 200ah capacity used per cycle". The value of 58.4V is that recommended by the dealer's technician.
                  In the Operation manual for the controller, the three stages are called Bulk, Boost, and Float, where Bulk stage is described as "where the battery voltage has not yet reached boost voltage and 100% of available solar power is used to recharge the battery". It seems to me then that bulk voltage should be higher than boost (absorb), which on this controller kicks in "When the battery has recharged to the Boost Voltage" - "every time the controller is powered on if it detects neither over discharge nor over voltage, it will enter into boost mode". I wonder then if I see what you are driving at - if the controller switches to Boost when it reaches the boost voltage of 58.4, it seems it will never reach the Bulk voltage of 58.8?
                  Oh, not sure if you need this info, but just to be complete, my back up is a 4.5kW generator, diesel motor of 10hp. I run it through two 24V battery chargers linked in series to produce 48V, and use it to recharge the batteries when I need to. I usually check voltage when the sun goes down, and if not up to 51.6V I run the genny for an hour or two on Boost before settling in for the night.
                  Thanks for you input.

                  Comment


                  • #10
                    Sub something is not right with that controller. You have a 3-Stage Controller. They use the terms Bulk, Boost, and Float. Same thing as Bulk, Absorb, and Float just different countries. It is important you understand Stage.
                    • Bulk is a Constant Current mode. Constant Current supplies full current capability from the panels until the battery terminal voltages reaches a SET POINT. In your case should be around 56.4 to 57 volts. With me so far?
                    • Boost or Absorb is a Constant Voltage mode which is higher than Bulk Set Point. Initially when it switches to Absorb the current will be full current from the panels until the voltage reaches the SET Point of say 58.4 volts. Once it hits the St Point will remain there and current will slowly taper off to ZEO until the battery voltage equals set point. Once the current tapers down to about 3% of C the battery is fully charged up and then switches to Float.
                    • Float is another Constant Voltage mode. Float voltage is less than Bulk Set Point and Absorb voltage. In your case around 54 volts. Assuming the batteries are fully charged up very litttle current will be flowing. Just enough to over come self discharge. If load is demanded that power comes from the panels if it is available, otherwise the battery will make up the shortage.


                    Now here is the deal. In RE applications does not matter if you use FLA or AGM. You only want 2 Stages, not 3. You only want Absorb and Float. The difference between FLA and AGM is the Voltage SET POINT. In most controllers it is easy to do this by simply setting Bulk = Absorb = x.xx volts per cell where x.xx is the voltage for the battery chemistry you are using. Just about all AGM batteries Absorb volt per cell is 2.41 volts or 57.8 volts on a 48 volt battery, and for 2.25 vpc for float (54 on 48 volt systems). For whatever reason your battery is a little higher voltage which bothers me.
                    MSEE, PE

                    Comment


                    • #11
                      Getting controller settings right!

                      Thanks Sunking, been doing a lot of research trying to understand this. My old Xantrex PWM controller didn't have the complexity this one has! I queried the dealer about your concerns that voltages setting they recommend are too high and he said that would be true with most AGMs, but that theirs can handle higher voltage.
                      1. I have left Boost/Absorb setting at 58.4V and Float at default setting of 55.2V.
                      2. I am at a loss as to how to set Bulk voltage. The controller seems to have parameters for only two stages. There is no parameter designated for Bulk, unless "Charging Limit" which is at default of 62V, controls Bulk voltage? Or does the controller automatically use the Boost voltage setting for Bulk?
                      3. If I change Charging Limit to, say 57V, then do I also need to change the default settings for OVD (64V) and OVR (60V)?
                      Thanks in advance for your advice.

                      Comment


                      • #12
                        Sub, man I am at a loss with the terms you are using and have to kind of guess what you are talking about.

                        Let me ask you a couple of questions.

                        1. Do you have a link to your controller manual I can look at?
                        2. What are the name or acronyms of the voltages settings you can set?
                        3. Do you have a link for the batteries you have? I know Europe and Australia use a different alloys in their lead than we do, so some of my voltages may be wrong for your application. I do not want to guide you wrong.

                        I gotta know how to translate to your terms.
                        MSEE, PE

                        Comment


                        • #13
                          Translation

                          1. A link to the manual - http://www.epsolarpv.com/en/uploads/...4723784755.pdf
                          My controller is the 60A model ET6415N.
                          2. Go to page 41 where you will see Table 8.1, a list of parameters for 12V system (multiply by 4 for 48V). All parameters can be changed from default settings to Options & Range, except for Battery Rated Voltage, which is automatically selected.
                          3. OVD = Over Voltage Disconnect
                          OVR = Over Voltage Reconnect.

                          Re your comments about lead etc, NZ does not have a battery manufacturing plant, all our deep cycle batteries are imported, which I guess explains why AGM batteries from China are so much cheaper than FLA types from USA. As per a previous post, there is no manufacturing ID on the batteries I have. Here is a link to the dealer's web site with info about the batteries -

                          http://www.aasolar.co.nz/AA%20Champi...Batteries.html

                          Cheers
                          Sub

                          Comment


                          • #14
                            Originally posted by Sub View Post
                            Thanks Sunking, been doing a lot of research trying to understand this. My old Xantrex PWM controller didn't have the complexity this one has! I queried the dealer about your concerns that voltages setting they recommend are too high and he said that would be true with most AGMs, but that theirs can handle higher voltage.
                            1. I have left Boost/Absorb setting at 58.4V and Float at default setting of 55.2V.
                            2. I am at a loss as to how to set Bulk voltage. The controller seems to have parameters for only two stages. There is no parameter designated for Bulk, unless "Charging Limit" which is at default of 62V, controls Bulk voltage? Or does the controller automatically use the Boost voltage setting for Bulk?
                            3. If I change Charging Limit to, say 57V, then do I also need to change the default settings for OVD (64V) and OVR (60V)?
                            Thanks in advance for your advice.
                            Let me see if I can understand you. The bulk charging voltage is between 0 volt to the volt you set absorb charge, Bulk charge is the first stage charge, it take the maximum current to charge the battery and the controller try to bring the battery voltage to absorb voltage as quick as possible, the absorb charge is set volt and limited current to charge the battery on the last 15% SOC from around 85% to 100%. it is the longest and hardest charge time. it take at least 4 hours on my battery bank.

                            Normally we don't set bulk charge volt unless some charge controller have the feature to re-bulk after it went above the absorb volt and drop back to bulk volt and the controller don't want to re-bulk charge too quick as may be the drop is too short and minimal.

                            The float rate is to just maintain the battery at full charge to prevent it from self discharge.

                            Hope this will help.

                            Comment


                            • #15
                              Getting it, thanks

                              Thanks for the input, I finally seem to have made sense of this!
                              My confusion stemmed from a couple of things -
                              1. The battery spec sheet recommended Bulk to be set between 58.4V and 59.6V, and Float to be set at 54.8V, but does not give a setting for Absorb/Boost, other than to say "Absorption time of one hour for every 200 amp hour capacity used per cycle".
                              2. The controller does not have user adjustable voltage settings for Bulk, only for Absorb/Boost and Float.
                              3. The supplier told me to set Absorb/Boost to 58.4V, and that left me floundering around wondering how to set voltage for Bulk. I now understand that Absorb/Boost setting also controls voltage for Bulk!

                              Ok, that leaves me with one question about the controller.

                              The controller has, as a Default setting for "Charging Limit - 62V", with optional user adjustable settings between 56V and 64V.

                              Is the default setting of 62V too high? If it is and I lower it, do I also need to change the default settings for Over Voltage Disconnect (now on 64V with optional settings between 60V - 68V) and Over Voltage Reconnect (now on 60V with options between 56V - 62V)?

                              Thanks.

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