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  • smart charger recommendation requested

    Hi. Do you have a recommendation for a smart charger for a deep cycle battery. I am interested in having a 12v sealed battery that is portable. I will be using the battery for very small loads while at a cabin. I would like to charge it using house hold current before going. I am not interested in connecting it to my small solar system and would prefer to be able to charge the portable 12v battery when needed. Thanks in advance for any help. Currently the only battery charger I have is a basic car battery one.

    Fred

  • #2
    Originally posted by Fred Jones View Post
    Hi. Do you have a recommendation for a smart charger for a deep cycle battery. I am interested in having a 12v sealed battery that is portable. I will be using the battery for very small loads while at a cabin. I would like to charge it using house hold current before going. I am not interested in connecting it to my small solar system and would prefer to be able to charge the portable 12v battery when needed. Thanks in advance for any help. Currently the only battery charger I have is a basic car battery one.

    Fred
    Hi Fred,

    There are some very good threads by member PNJunction on AC-fed battery chargers. How large (in AmpHours, AH) is your portable battery?
    You are correct that a car battery charger is not ideal, especially if you have an AGM (sealed) battery.
    SunnyBoy 3000 US, 18 BP Solar 175B panels.

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    • #3
      100-125 Ah

      It should be in the range of 100-125 Ah.

      Comment


      • #4
        You do not need or want a Smart Charger with a VRLA battery. It would be a waste of your money. 3-stage chargers are fast but, but do damage by gassing the batteries, and you never want to gas a VRLA battery. The best, kindest, and gentlest chargers are what industry and commercial users use. A FLOAT CHARGER of the appropriate voltage and current. Plug them in and forget it until ready to use the battery. They are very simple and CHEAP. Most good float chargers can double as a 2-mode charger of Float and Equalize. To have that ability all that is required is a charger with a simple user adjustable output voltage. The main difference between a Float and 3-Stage charger is time. A 3-stage charger can take as little as 8 hours or up to 12 hours if fully discharged assuming it has a C/10 charge current. A C/10 Float charger can take up to 14 to 16 hours. If you want speed, you have to sacrifice money and battery. cycle life. Which one do you want? It is that simple.

        All you need is a simple Marine or RV grade 12 volt Float battery charger with an adjustable output available at any Marine/RV shop and even Sears, Lowes, Walmart, and the hardware stores. You can even use a 12 volt DC power supply ham radio operators use to power their equipment and charge their batteries. options are cheap and endless. All you got to figure out is what size in current. If you really have a Sealed VRLA of 60 AH or less, will cost you no more than $40 to $60 for a 4 to 5 amp model. Additional resources are by using any Fire/Burglar Alarm Panel wallwort charger. Connect it to the battery, plug it in, and walk away. Here is an example of a good Marine charger.

        Be aware consumer grade Float chargers have fancy gimmick marketing names like Maintainer. Catch is you have to look closely at the current a smost that use the gimmick Maintainer are usually pretty small of 1 amp of less. Assuming you have a 12 volt Sealed VRLA battery is likely fairly small of less than 60 AH. Taht said most likely need a 3 to 5 amp Float charger.
        MSEE, PE

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        • #5
          Originally posted by Fred Jones View Post
          It should be in the range of 100-125 Ah.
          If VRLA then 5 to 10 amps is more than enough.
          MSEE, PE

          Comment


          • #6
            Perfect but another question if you have time...

            The NOCO Genius 12v 4 Amp Marine On-Board Battery Charger GENM1 is exactly what I am looking for.... I am more interested in taking good care of the battery than speed so this looks good. Assuming I have a 100ah battery, once it is completely charged, do you have any idea how much energy it requires to maintain it daily?

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            • #7
              Lets back up a bit.

              You are using a sealed "100ah" battery as portable power ?

              You use it, and when it's low, you want to recharge it ?

              It is not for float standby, but just for charging after each use ?

              I would think you need about 15 or 20 amps of charging current from a charger, to rebulk the battery in a couple hours, a 5A
              trickle charger would need 10+ hours to replace 50ah of usage. But you don't want such a large charger you overheat the battery and damage it.

              Are these the conditions you need met ?
              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


              • #8
                Originally posted by Fred Jones View Post
                The NOCO Genius 12v 4 Amp Marine On-Board Battery Charger GENM1 is exactly what I am looking for.... I am more interested in taking good care of the battery than speed so this looks good. Assuming I have a 100ah battery, once it is completely charged, do you have any idea how much energy it requires to maintain it daily?
                As Mike and I said the 4 to 5 amp model is a good fit providing you do not daily cycle the battery. If that is your use pattern then it is a great fit. Otherwise just look for a higher power charger. If you are going to cycle daily, then a Flooded Lead Acid battery is a better fit with a 3-stage charger. Charger and battery must fit the application. So define your needs.

                Any 3-stage charger has a Float MODE as the 3rd and last stage. It is a Constant Voltage profile. Once the battery reaches FLOAT voltage all charging stops as that is just the nature of the battery. Th eonly current that flows is that of the battery Self Discharge current. Float maintains the battery at 100% state of charge until ready to use.

                Telecom and all utilities use Float Charging with a twist. Theie charger are sized not only to charge the batteries but also run the load for a specified period of time like 4 to 24 hours. The load equipment uses commercial Ac power via the Rectifier (that is what a charger is). If commercial power fails, the batteries are already on line and take over until commercial power is restored, generator starts up and takes place of commercial power, or until the batteries are discharged. When power is restored the Rectifiers charge the batteries back up and powers the load equipment. They use VRLA and FLA batteries made to be charged very fast. They are not deep cycle batteries and close cousin to Starter batteries or car batteries. That is how all critical mission communications is powered.

                All batteries can be Float charged, only real difference is how fast you want them to charge. If your battery can be charged at 1C or higher can be float charged in a few hours. Otherwise slower is better, and if you do not need daily cycle then Float is for you. AGM's or VRLA can be charged in 1 of 2 ways. Single Stage Float, and 2-Stage Absorb and then Float.

                Both Absorb and Float are the exact same algorithm of Constant Voltage. Only difference is the voltage. Absorb voltage is higher than Float to force the rectifier go into Constant Current limit until the battery voltage rises to match the rectifier voltage, and then current tapers off to around 2 or 3 percent of C. When that happens, the voltage is lowered to Float and remains in Float until you turn it off, or in the case of Solar when the sun goes away and then you are discharging if there is any load. 2 and 3-stage is just faster, not better. Avoid 2 and 3-stage if not needed.
                MSEE, PE

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                • #9
                  For your non-mars-mission critical needs, I recommend (and use myself) a Samlex / Cotek BP-1210a. ... among others...

                  14.4v absorb, 13.6v float, 10A. Built well, despite just looking like a small brick. Samlex quality, which test to specs. If my Fluke's don't jive with the specs, out they go!

                  Unless you are thinking of running an Enersys/Odyssey that mandates "seeing" 14.7v, the Cotek BP-1210a will do just FINE. No user interaction, and amazingly, an on/off switch!

                  Does a fine job on Optima, East-Penn/Deka, and Exide Edge agm's.

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                  • #10
                    Infrequent use

                    This would not be for cyling. The 100ah AGM battery would be charged and taken to the cabin infrequently. Once there I would use it for a small load and stop around 12.4 volts (charging up cells phones etc.) After returning home, I would then want to charge it to be ready for the next trip...which is infrequent. This will be an expensive way to charge a cell phone... but since I also have a AGM battery in my small solar setup, I was thinking I would use this charger as well in case the voltage on that battery was low and we were experiencing a lot of cloudy days. I really appreciate your comments. I enjoy the technical discussion and am still trying to wrap my head around this stuff. Thanks again.

                    Comment


                    • #11
                      Originally posted by Fred Jones View Post
                      This would not be for cyling. The 100ah AGM battery would be charged and taken to the cabin infrequently. Once there I would use it for a small load and stop around 12.4 volts (charging up cells phones etc.) After returning home, I would then want to charge it to be ready for the next trip...which is infrequent. This will be an expensive way to charge a cell phone... but since I also have a AGM battery in my small solar setup, I was thinking I would use this charger as well in case the voltage on that battery was low and we were experiencing a lot of cloudy days. I really appreciate your comments. I enjoy the technical discussion and am still trying to wrap my head around this stuff. Thanks again.
                      OK any basic charger will work including the one PN recommended (Two Stage). Really comes down to how much you want to spend on Bells and Whistles.

                      FWIW the three batteries PN mentioned are high end Pure Lead batteries. As such they have a unique voltage requirement at odds with Lead Anatomy deep cycle alloys.
                      MSEE, PE

                      Comment


                      • #12
                        OPTION 2:

                        Tecmate-Optimate 6.

                        It is only 5A, but one of the smartest on the planet. Given the nature of his application which is light discharge, and not cyclic, even at only 5A, this isn't a problem - the battery will die of old age first before any degradation of "walking it down" with a lower amperage charger will be seen. Less than 5A, not recommended.

                        The other good thing is that the Optimate's float is only a 50% duty cycle. 30 mins on, 30 mins off, AFTER the initial 12 hour test has passed, and every 12 hours thereafter.

                        The Optimate is about the only charger I'd feel comfortable with leaving on an agm, especially in high-heat storage conditions. For that matter, flooded too.

                        While the Cotek is fine, my money *in this application* would go to the Optimate. Either one is a plug-n-play with no user interaction, which actually gets the job done well. The Optimate is a bit more informative IF you want to interpret the led lighting - or walk away - your choice.

                        Comment


                        • #13
                          Originally posted by PNjunction View Post
                          For your non-mars-mission critical needs, I recommend (and use myself) a Samlex / Cotek BP-1210a. ... among others...

                          ......... Cotek BP-1210a will do just FINE. No user interaction, and amazingly, an on/off switch!

                          Does a fine job on Optima, East-Penn/Deka, and Exide Edge agm's.
                          How does it determine flooded or AGM ? Or does it charge by sensing the IV curve as the charge starts to flatten out ?

                          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


                          • #14
                            For standard lead-calcium agm's, the usual manufacturer's absorb is 14.4v, which the Cotek does in bulk. Once it reaches that, it switches to CV at 14.4, and when the absorb current is down to 1.5A, then it switches to 13.6v float.

                            This would even be ok for Optimas, that *aren't* doing daily cycling. If they are, or if you are using Odysseys that also do daily cycling, then 14.7v would be a better bet with a different charger.

                            The Optimates do it differently. They bulk to 14.3v, and then oscillate from about 13.6v and back up to 14.3v. A charge confirmation is performed by taking a small break, and doing a very tiny charge at 13.6v. If it detects that more than 200ma is needed to maintain that voltage, it will switch back to the full power oscillating absorb. Repeat as necessary. When the charge retention test is finished (no higher than 200ma at the temporary 13.6v charge), it waits 30 minutes to do a voltage retention. If the voltage falls too fast, it will repeat this whole process. If it passes the 30 minute voltage retention, then it will then proceed to a longer term 12 hour voltage retention test. If that passes, it proceeds to a 13.6v float, which is a 50% duty cycle every 30 minutes. Every 12 hours another voltage retention test is taken.

                            The oscillating absorb helps to balance cells. It does so mainly by utilizing the rise-time of the fully charged batteries to get more charge into lower cells to catch up. By not holding at a steady state fully absorbing, many many rise-times and subsequent charges to the cells that need it are brought up. I did this to a pack of Cyclons which I unbalanced just to make sure.

                            In the meantime, it looks for high IR, and also aberrant voltage/ current ratios while charging to detect bad cells, or the need to go into a 16v desulfate (VERY low current, and VERY fast pulse - not enough to harm a vehicle). If no external cables are detected, it will actually go to 22v - again with super fast short pulses. This is not like pumping 16/22v into vehicle wiring with large continuous currents, so it is safe. In fact, it WANTS to go to 22v if it deems necessary, but the impedance of the external wiring attached to the battery actually attenuates it to 16v.

                            Thus if you have a severely discharged batttery that needs this higher voltage kick to get back to a normal state for normal charging, you want to remove it from the vehicle. NOT to protect the vehicle, as the super fast / super low current is not enough to harm the vehicle, but so as not to attenuate the signal down to 16v, but allow it to run full blast to 22v to do a better job. It senses these things.

                            A lot of guys see this and falsely assume that this will harm vehicle electronics without knowing the duty cycle, super low currents, and impedance detection. They have a pretty good faq on it at the UK site.

                            Are these lab-quality - no, but pretty smart. Unlike some undocumented "speedchargers" which have a tendency to do this behind your back:

                            https://www.youtube.com/watch?v=5BF8FB__iR8

                            I've witnessed it myself on brand new good batteries, and watched them get fat and die.

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