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  • another battery and charger question...

    So as I continue to dig I've come up on a few more questions in regard to "what type of battery would be best for my intended use case?"...

    As a reminder my use case is "I want to be able to have a small amount of power if the grid went totally south..."

    I define the use case above as follows:
    1) Solar setup is just sitting in pieces in the storage locker until it is needed.
    2) The battery must be maintained while in the storage locker so it is still in good condition when it is needed.
    3) The battery must be maintained when it is being used.

    Question #1 - this question is in regard to item #2 above. I want to use the battery type that will require the least amount of maintenance, both while in storage as well as in use. I have decided that this will be one of the following:
    1) U.S.Battery 12volt FLA
    2) U.S.Battery 12volt AGM

    The thing that I'm concerned about is getting distilled water when there is no power in the case of the FLA.. I have read that the distilled water that you get at the grocery store is actually distilled by some chemical process and still has impurities in it which can damage the battery. So, I am unsure how/where to get "truly" distilled water for my battery needs. I believe that in the case of an AGM battery it is closed and so this is not a problem but they obviously cost more. Both require you to keep them charged correctly so they don't get build up on the plates or rolls in the rolls in the case of the AGM.

    Is the above correct? or do you have any comments on the FLA battery and the maintenance of it when there is no AC power available (and all that means..)?



    Question #2 - I'm going to go with a turnkey folding panel setup which includes the solar charger as part of the unit. That means I only need to purchase the AC tending, floating, maintenance (whatever you want to call it) charger for the battery while it is in the storage unit. Can you point out a few recommendations for this? I've seen them all over the map and they mix the terminology such that it is very unclear what it is I'm looking for exactly.. Also, would the same type of charge unit work for either the AGM or FLA battery?


    So, bottom line to the two questions are 1) what type of battery: AGM or FLA & 2) what type of charger for either while in storage

    thanks again for your help,
    david

  • #2
    Originally posted by drcii View Post
    So as I continue to dig I've come up on a few more questions in regard to "what type of battery would be best for my intended use case?"...

    As a reminder my use case is "I want to be able to have a small amount of power if the grid went totally south..."

    I define the use case above as follows:
    1) Solar setup is just sitting in pieces in the storage locker until it is needed.
    2) The battery must be maintained while in the storage locker so it is still in good condition when it is needed.
    3) The battery must be maintained when it is being used.

    Question #1 - this question is in regard to item #2 above. I want to use the battery type that will require the least amount of maintenance, both while in storage as well as in use. I have decided that this will be one of the following:
    1) U.S.Battery 12volt FLA
    2) U.S.Battery 12volt AGM

    The thing that I'm concerned about is getting distilled water when there is no power in the case of the FLA.. I have read that the distilled water that you get at the grocery store is actually distilled by some chemical process and still has impurities in it which can damage the battery. So, I am unsure how/where to get "truly" distilled water for my battery needs. I believe that in the case of an AGM battery it is closed and so this is not a problem but they obviously cost more. Both require you to keep them charged correctly so they don't get build up on the plates or rolls in the rolls in the case of the AGM.

    Is the above correct? or do you have any comments on the FLA battery and the maintenance of it when there is no AC power available (and all that means..)?



    Question #2 - I'm going to go with a turnkey folding panel setup which includes the solar charger as part of the unit. That means I only need to purchase the AC tending, floating, maintenance (whatever you want to call it) charger for the battery while it is in the storage unit. Can you point out a few recommendations for this? I've seen them all over the map and they mix the terminology such that it is very unclear what it is I'm looking for exactly.. Also, would the same type of charge unit work for either the AGM or FLA battery?


    So, bottom line to the two questions are 1) what type of battery: AGM or FLA & 2) what type of charger for either while in storage

    thanks again for your help,
    david
    Question #1. Yes an AGM battery will require much less "maintenance" then a FLA battery. It will also cost almost twice as much as the FLA so that would be your decision to make. Also unless you perform a lot of EQ charging to a FLA battery, it will not loses that much water but you may still need some amount added to keep the plates covered.

    Question #2. A quality charge controller needs to have the logic to charge an AGM along with FLA chemistry batteries. Some cheap car battery charges say they can do AGM type but may not charge them correctly. One of the chargers that has been recommended is the Optimate 6. I do not have any hands on experience with that charger but if I were you I would look into that or something along the same quality (and price). If your batteries are important then don't go cheap on the charger.

    Comment


    • #3
      Maintained in a storage locker? Ok, your best bet would be agm. Still, it can't be airtight for safety in case something goes wrong.

      US Battery's 12 lineup only goes to 234ah and the Tecmate-Optimate 6 will handle this or any smaller capacity one nicely for maintenance or for *occasional* medium-level recharge recovery.

      "Maintained when being used"? If you mean an endless load drawn upon the batteries with the charger attached, that usually means an endless absorb cycle because your load will not allow the charger to actually finish. That's bad. If that is what you mean, then your only choice is something that doesn't go beyond 13.8v, like a power supply. A Samlex SEC series charger can be dip-switch set to do just 13.6v if you wish. A NOCO Genius 7200 or higher also has a "maintenance" or "power supply" mode at 13.5v. Still, you need to be on top of it and allow for a full charge on a regular basis, or your batteries will suffer.

      But if you aren't using the battery fulltime, and just maintaining, the Optimate 6 would be a fine bet. So would a Battery-Minder 2012-AGM, (2A) or their 12248 model (up to 8a charge). These are about the best you'll find in this category. Battery Minder has several models with slightly differing voltages for both absorb and float, so pick what you need. Docs are available online, and you can easily see the specs.

      For the totally hands-off, no-decisions to make solution, Optimate 6.

      Comment


      • #4
        Sun Eagle & PNjunction,

        Thank you both. I've decided on the EcoWorthy 120 watt folding panel setup and the Optimate 6. I'm still considering the battery. I'm trying to decide between the US AGM 31 (12v 100ah@20) and the US 27DC XC2 (12v 105ah@20). I'm trying to decide if the value of sealed & low/no maintenance is worth basically $100. I'm leaning toward thinking that it is, at least for my particular use case.

        Sun Eagle... You've been an awful lot of help over these past couple of weeks. I really appreciate your quick and informative responses.

        PNjunction... your name brought back some really old memories.. are you familiar with the Gummel Poon model of a BJT? It's been a long time since I've thought of that.. I verilog for FPGA's these days..

        thanks again,
        david

        Comment


        • #5
          Originally posted by drcii View Post
          ... I've decided on the EcoWorthy 120 watt folding panel setup and the Optimate 6. I'm still considering the battery. I'm trying to decide between the US AGM 31 (12v 100ah@20) and the US 27DC XC2 (12v 105ah@20). I'm trying to decide if the value of sealed & low/no maintenance is worth basically $100. I'm leaning toward thinking that it is, at least for my particular use case.
          Well the storage-locker kind of mandates the agm. An fla really needs good venting / outdoor installation, whereas an agm can exist indoors, but only if it isn't in a totally encapsulated compartment if things go wrong - it too can vent with overcharge.

          Just be aware that if you intend to take either battery down to 50% DOD, it will take about 10 hours to really recharge back to full. And depending on your solar insolation hours, that could mean DAYS, since solar insolation hours are not sunrise-to-sunset. Those insolation hours depend on your geographic location, and ideally calculated for worst-case winter hours.

          AND, if you are going with the FLA, the *minimum* charge rate is C/12, (C/8 is typically the max for fla) so 105/12 = 8.75A, and your Ecoworthy panel is only capable of 6.6A under absolutely best conditions. What will happen now, is the battery in a stationary environment will stratify, ie the electrolyte gravity is uneven, and the bottom of the cells get eaten up by the heavier level of acid down there. So your panel is insufficient.

          The U.S. Battery agm has a surprisingly low recommended recharge current maximum - which is not part of the allure of high quality agm's, so I don't know what's going on there. I'm puzzled quite frankly, and would ask them about that. Typically an agm is rated to about having twice the CAR or "charge acceptance rate" of an FLA, which usually means a max of about .25 to .3C - ie for this battery, 25 to 30a max. I'd call them - perhaps their charging instructions are a typo carried over from their "float" specifications. Either that, or they are dumbing-it-down for total cya.

          If you are just solar floating after an ac charge that's one thing, but if you are going to cycle EITHER one, you'll want more panel.

          Many threads on that, so I'll stop here.

          PNjunction... your name brought back some really old memories.. are you familiar with the Gummel Poon model of a BJT? It's been a long time since I've thought of that.. I verilog for FPGA's these days..
          I had to look that up! However, I have been known to go bipolar in some threads. The name was just thought up as having to do with solar cells when I initially first joined...

          Comment


          • #6
            Originally posted by PNjunction View Post
            Well the storage-locker kind of mandates the agm. An fla really needs good venting / outdoor installation, whereas an agm can exist indoors, but only if it isn't in a totally encapsulated compartment if things go wrong - it too can vent with overcharge.

            Just be aware that if you intend to take either battery down to 50% DOD, it will take about 10 hours to really recharge back to full. And depending on your solar insolation hours, that could mean DAYS, since solar insolation hours are not sunrise-to-sunset. Those insolation hours depend on your geographic location, and ideally calculated for worst-case winter hours.

            Many threads on that, so I'll stop here.



            I had to look that up! However, I have been known to go bipolar in some threads. The name was just thought up as having to do with solar cells when I initially first joined...
            When you are not bipolar, you seem to Field questions Effectively.
            SunnyBoy 3000 US, 18 BP Solar 175B panels.

            Comment


            • #7
              Heh, I suppose so!

              To add to that, another warning about FLA is that unless the battery is *specifically* designed to be a float-only battery like you find in telco's and other commercial standby setups, THESE more general purpose types of fla batteries must get some active use once in awhile. They can stratify on endless float too! Simply put, you gotta' bubble-up to mix the electrolyte once in awhile, otherwise the effect is similar to stale salad-oil dressing.

              So here too, if mostly standby is desired, then an agm is your better fit. Note too that even very tall agm's can stratify, so don't consider it a blanket statement. Regular proof-of-performance testing is recommended - even some sort of activity is better than none at all, unless the battery is designed specifically for that.

              Also, to get the most from a new battery, you really should put some cycles on it to get the plates fully formed, and get the most ah capacity from it. For an agm, that is about 5-10 cycles. Going to 50% DOD is far enough. For FLA, that is typically 50-100 cycles! So just coming home with a new battery and putting it on float right away is not the healthiest thing to do either.

              Now we have a problem with the Optimate 6. It is not sufficient as a *charger* to do repetitive cycling like this on those large batteries. Maintaining, or an occasional recharge no problem, but the FLA you've chosen mandates at least 8A. In this case, if you want to keep the charger small, a Battery Minder 12248 model might be considered, but if you lose power or the connection, it will default back to 2A/Gel. Nevermind the desulfation if you want, as it only uses frequency, and not high voltage spikes. The regular charging circuitry, voltages, temp-comp and build is great. Just keep those SAE quick-disconnects tight. These are just two options.

              These guys have some pretty good reading about it all too:

              http://support.rollsbattery.com/support/solutions

              Good stuff, even if you don't go Rolls.

              Comment


              • #8
                I understand the charging issue with the FLA batteries and it seems my current setup will not handle a 105ah FLA battery... Of course the Walmart cheapy that says 105ah is actually about 75ah (from another member here).. so it looks as if, I would just make it with the 6.6amp panel setup (of course that is assuming 100% of listed current output, which is likely not the case most of the time)..

                But, in regard to the AGM batteries, I'm unclear... Would my setup handle the 100ah AGM batteries or not?

                I would like to get as large a capacity battery setup as possible and am willing to pay for it, but I'm unclear if my panel setup (6.6amps best case) can handle it.

                If I cannot get the 100ah AGM then I'll have to either get a second set of panels and run them in parallel through the same charger or move down in my battery selection.

                I see the batteries below as being fine for the single panel setup I talk about above no matter what the answers coming back are, but again I would like to get the 100ah AGM if I can....

                Mighty Max AGM at 55ah (does not list charging requirements)
                U.S. Battery AGM at 35ah (3 to 5 amps)

                thanks again,
                david

                Comment


                • #9
                  PNjunction,

                  I've been thinking about what you said and I obviously don't understand something...

                  I'm confused about the following comment. I'm not arguing with you about it, I simply don't understand it and I need clarification so I can get the right battery.

                  Your comment of:

                  "AND, if you are going with the FLA, the *minimum* charge rate is C/12, (C/8 is typically the max for fla) so 105/12 = 8.75A, and your Ecoworthy panel is only capable of 6.6A under absolutely best conditions. What will happen now, is the battery in a stationary environment will stratify, ie the electrolyte gravity is uneven, and the bottom of the cells get eaten up by the heavier level of acid down there. So your panel is insufficient.".

                  ok, I take that to mean that the charger from the panels cannot charge this battery because the panels can only produce 6.6amps. Ok, I got that, but I'm confused in that the Optimate 6 that i purchased is a 12volt charger and can only produce 5amps and it can charge the battery. I'm misunderstanding something somewhere...

                  Once I get the issue above resolved I'm actually interested in understanding if both my Optimate 6 as well as my panel setup can handle the U.S. Battery 105ah AGM...

                  I really appreciate your help on this. I'm almost there, but I need to understand this before I go spend $200 on a battery.

                  thanks again,
                  david

                  Comment


                  • #10
                    Ok, in the wet-cell FLA case where electrolyte can slosh around, the electrolyte can "stratify" if left sitting around with no movement, or too little recharge current which is bad. Basically that means that the electrolyte has differing layers if you will, of unequal acid/water ratio, aka SG, or specific gravity. Kind of like salad-oil dressing left to sit around.

                    So you need to make sure the electrolyte gets stirred up once in awhile. That can be done by either physical movement, such as in a vehicle, or by ensuring that your charge current is enough to make the electrolyte bubble (not boil!) up to do the mixing. Anything much below C/12 won't do any bubbling.

                    Back to AGM. Unless they are very physically tall, like in some industrial environments, agm's don't suffer from stratification, as the electrolyte is wicked/absorbed into a thin material between the plates and tends not to stratify.

                    The Optimate 6 will charge up that US Battery agm, and maintain that well. One just has to be a bit cautious knowing the difference between maintain and charge though, and I wanted to make sure you were ok with that. While one *can* charge up a large agm battery with a small amount of current, if you do it often enough as your sole source of cyclic charging, it will walk-down your capacity over time. Your 100ah battery after a year could become a 75ah *internally* for instance.

                    So if you were planning on cycling this thing down to say 50% DOD daily, then you definitely need to meet at least 0.1C, preferably a little more like 0.2C charge capability for that 100ah agm. That would be 10-20A. Again, I'm still at a loss why US Battery does not list this common specification. I suspect a typo left over from their float spec, or are dumbing it down so that the shade-tree guy doesn't try to hit it up with a 200ah unregulated wheeled shop charger from the 60's.

                    Since your needs seem to be more inline with random standby/backup duties, and not daily heavy cycling, then the Optimate 6 will do ok on nearly any agm battery you choose. Your solar panel will do fine too, but it will take a few days of exposure to recharge if the batteries are heavily discharged, not one day. Go heavy-duty daily cyclic, and now you need a larger charger.

                    I would prefer the US Battery over the Mighty-Max for sure, as the MM is just a generic ups-style agm. However, if they can't straighten out their max current charging rating and that is worrisome, then an East Penn / Deka agm which CAN do 0.3C as stated in their docs, would be a great alternative. Don't forget Trojan, Lifeline, Concord, etc.

                    Heck, for nearly the same purposes you are using things for, I'm running a 75ah Blue Top Optima D31M (light colored case, not black!) in standby/float.

                    So this is the juggling act we all face. It all depends on knowing exactly how much power you need to support your load daily. Then secondly, figuring out if you have enough solar to keep the battery healthy, and if you need to recharge in only a single day, which many desire.

                    So far all we've discussed is how to keep a battery charged and healthy. But right now, you may be vastly under or over-estimating your actual power needs, even in a standby/backup scenario. This whole system could be a total unreliable joke, or total overkill just to keep a laptop charged. That kind of thing.

                    If you want to zero in on things, then you'll want to start measuring your power needs for when the lights go out, and for how long you need to keep it running. You measure either amperage with say a multimeter, or use the wattage ratings, or measure ac wattage with a Kill-A-Watt meter and we go from there.

                    Comment


                    • #11
                      Originally posted by drcii View Post
                      PNjunction,

                      I've been thinking about what you said and I obviously don't understand something...

                      I'm confused about the following comment. I'm not arguing with you about it, I simply don't understand it and I need clarification so I can get the right battery.

                      Your comment of:

                      "AND, if you are going with the FLA, the *minimum* charge rate is C/12, (C/8 is typically the max for fla) so 105/12 = 8.75A, and your Ecoworthy panel is only capable of 6.6A under absolutely best conditions. What will happen now, is the battery in a stationary environment will stratify, ie the electrolyte gravity is uneven, and the bottom of the cells get eaten up by the heavier level of acid down there. So your panel is insufficient.".

                      ok, I take that to mean that the charger from the panels cannot charge this battery because the panels can only produce 6.6amps. Ok, I got that, but I'm confused in that the Optimate 6 that i purchased is a 12volt charger and can only produce 5amps and it can charge the battery. I'm misunderstanding something somewhere...

                      Once I get the issue above resolved I'm actually interested in understanding if both my Optimate 6 as well as my panel setup can handle the U.S. Battery 105ah AGM...

                      I really appreciate your help on this. I'm almost there, but I need to understand this before I go spend $200 on a battery.

                      thanks again,
                      david
                      The problem is that we tend to make absolute statements where qualified (hedged) statements are more accurate.

                      1. A grid fed charger can take a virtually unlimited time to get to 100% SOC, while a PV charge system has to get all (or as much as possible) of the work done within one solar day (max of 8 hours or so if you include the low current but still useful tails.)
                      2. The C/12 to C/8 rate is idea for Bulk stage charging as fast as it can be done safely. Gets it done in the shortest amount of PV working hours.
                      3. That rate is high enough to be capable of causing gassing near the end of the charging process. That will stir the electrolyte and prevent stratification. Stratification can lead to an incomplete charge and to uneven distribution of the active material on the plates causing problems eventually. If you use a lower current for a longer time, as long as the voltage gets above the gassing voltage at some point and stays there long enough to mix the electrolyte, the current value is not important.
                      SunnyBoy 3000 US, 18 BP Solar 175B panels.

                      Comment


                      • #12
                        Originally posted by inetdog View Post
                        The problem is that we tend to make absolute statements where qualified (hedged) statements are more accurate.

                        1. A grid fed charger can take a virtually unlimited time to get to 100% SOC, while a PV charge system has to get all (or as much as possible) of the work done within one solar day (max of 8 hours or so if you include the low current but still useful tails.)
                        2. The C/12 to C/8 rate is idea for Bulk stage charging as fast as it can be done safely. Gets it done in the shortest amount of PV working hours.
                        3. That rate is high enough to be capable of causing gassing near the end of the charging process. That will stir the electrolyte and prevent stratification. Stratification can lead to an incomplete charge and to uneven distribution of the active material on the plates causing problems eventually. If you use a lower current for a longer time, as long as the voltage gets above the gassing voltage at some point and stays there long enough to mix the electrolyte, the current value is not important.
                        Do you think that this two-bank temperature compensated Deltran float charger (http://www.amazon.com/Battery-Tender...+++-controller) could keep two pairs of T-105s healthy?

                        I realize that after they are discharged, a higher amp charger would be needed to recharge them.

                        Comment


                        • #13
                          Originally posted by lkruper View Post
                          Do you think that this two-bank temperature compensated Deltran float charger (http://www.amazon.com/Battery-Tender...+++-controller) could keep two pairs of T-105s healthy?

                          I realize that after they are discharged, a higher amp charger would be needed to recharge them.
                          I do not know. It would be best if charging voltages were adjustable, since there are chemistry differences even among AGMs that could make a slightly different float voltage useful.
                          Possibly someone like PNJunction could provide some more specific information.
                          SunnyBoy 3000 US, 18 BP Solar 175B panels.

                          Comment


                          • #14
                            Personally, in your situation my preference would be the Samlex 24v charger.

                            Those BT's are really designed for agm, and as such run at about 14.6v absorb, and hold until about 125-250ma end-current before dropping to a 13.2v float with agm, which was hotly contested as being too low from some circles. And at only 1.25a, they might be too little with a T105, possibly just staying in absorb until it times out. I'm not sure how the BT would react on a flooded.

                            If you want to go this route with 24v, then *maybe* the Battery Minder 24041 4A model would better suit your purposes. Or maybe two, one for each pair. There is a BC2AY accessory that includes clamps and the "smart" y-connector (210AY connector). At this point, be sure to get the ABS-248, which is the "At Battery Sensor" for temp comp, rather than relying on the small outboard ambient dongle. My 12248 came with that abs sensor, but wise to check. Note that there are "aviation specific" models, so the generic 24041 would be what you'd want and not an aviation version designed for specific aviation battery brands.

                            You can get great docs online explaining all the voltages, current, and charge profile in the 24041 manual. See page 34 for a graphic representation and see if it fits your purpose. Keep any SAE quick-disconnects tight.

                            I've mentioned it before, but the whole desulfation thing is a turn off to some and there are other threads about that here. Just know that they are not using high-voltage pulses, but a frequency sweep. Even if you don't place any trust in that, the charger build, engineering, active temp-comp, precise voltages etc means you can safely ignore the desulfation feature as if it wasn't there if you like.

                            Comment


                            • #15
                              Originally posted by PNjunction View Post
                              Personally, in your situation my preference would be the Samlex 24v charger.

                              Those BT's are really designed for agm, and as such run at about 14.6v absorb, and hold until about 125-250ma end-current before dropping to a 13.2v float with agm, which was hotly contested as being too low from some circles. And at only 1.25a, they might be too little with a T105, possibly just staying in absorb until it times out. I'm not sure how the BT would react on a flooded.

                              If you want to go this route with 24v, then *maybe* the Battery Minder 24041 4A model would better suit your purposes. Or maybe two, one for each pair. There is a BC2AY accessory that includes clamps and the "smart" y-connector (210AY connector). At this point, be sure to get the ABS-248, which is the "At Battery Sensor" for temp comp, rather than relying on the small outboard ambient dongle. My 12248 came with that abs sensor, but wise to check. Note that there are "aviation specific" models, so the generic 24041 would be what you'd want and not an aviation version designed for specific aviation battery brands.

                              You can get great docs online explaining all the voltages, current, and charge profile in the 24041 manual. See page 34 for a graphic representation and see if it fits your purpose. Keep any SAE quick-disconnects tight.

                              I've mentioned it before, but the whole desulfation thing is a turn off to some and there are other threads about that here. Just know that they are not using high-voltage pulses, but a frequency sweep. Even if you don't place any trust in that, the charger build, engineering, active temp-comp, precise voltages etc means you can safely ignore the desulfation feature as if it wasn't there if you like.
                              Yes, Samlex has been my first choice ... I am just looking at all possible options before I start. Thanks.

                              Comment

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