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  • #16
    Originally posted by mapmaker View Post
    ... most full featured [B]inverter/chargers [/B]will cut back the charging current so as not to overload the generator.
    And there is the rub, as a simple charger-only unit will have no idea of your other loads.
    SunnyBoy 3000 US, 18 BP Solar 175B panels.

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    • #17
      Originally posted by mapmaker View Post
      For me the point is to make the fuel cost as little as possible. I usually advise folks to get a smaller generator, and have a [B]longer[/B] run time to charge the batteries.
      Then you are over looking something then. You want your charger to load the genny to about 75% capacity to get maximum efficiency from your fuel burn. Second thing is if you do not get at least a C/12 to C/10 charge rate EQ will either take forever, or never get there.
      MSEE, PE

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      • #18
        Originally posted by SDC View Post
        Correct me if I'm wrong Sunking you are talking about what Iota names a dual voltage jack. Right? According to their documentation, that allows the user to select output voltage of 13,6V or 14,2V. As other mentioned, 14,2 is nowhere near EQ voltage for FLA..
        Yest that is what I am talking about but that is a moot point because you are going to open the unit up and adjust to correct voltage and never use the jack to begin with. With the Iota you have a uni-tasker and can only do one thing either a quick charge or EQ charge. To get a multi-tasker will require mo money and for off-grid is unnecessary.
        MSEE, PE

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        • #19
          Originally posted by Sunking View Post
          Originally posted by mapmaker View Post
          For me the point is to make the fuel cost as little as possible. I usually advise folks to get a smaller generator, and have a [B]longer[/B] run time to charge the batteries.
          You want your charger to load the genny to about 75% capacity to get maximum efficiency from your fuel burn. Second thing is if you do not get at least a C/12 to C/10 charge rate EQ will either take forever, or never get there.
          Some generators are most efficient at closer to 100% of their continuous ratings. In my preceding post, just define "fully loaded" to mean "loaded to peak efficiency". It will be different for every generator.

          As for needing a C/12 rate of recharge... you are correct that at least one battery manufacturer recommends a C/10 rate, but most do not. It's quite possible to charge many FLA batteries with a C/20 rate. I agree that it might take a long time.

          My point is that there is at least a 100% range in acceptable charging currents. In some systems (where charging is the major generator load) that means there is a 100% range in acceptable generator sizes. In many circumstances (but not all) I recommend that folks avoid the high end of the generator size range. A smaller generator means less investment in generator, and may mean lower fuel costs.

          --mapmaker
          ob 3524, FM60, ePanel, 4 L16, 4 x 235 watt panels

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          • #20
            Originally posted by Sunking View Post
            Yest that is what I am talking about but that is a moot point because you are going to open the unit up and adjust to correct voltage and never use the jack to begin with. With the Iota you have a uni-tasker and can only do one thing either a quick charge or EQ charge. To get a multi-tasker will require mo money and for off-grid is unnecessary.
            Sunking, I think I have missed some lessons here and I hope you will help me catch up. With the IOTA, everything I read says it is a four stage charger. When they say it is a 30 amp converter / battery charger am I getting the full 30 amps to my battery. If not, the IOTA is useless to me except a way to convert my AC generator power to DC power.

            I looked at the Samlex chargers and their lititure states they have to charge with no load on the batteries. I am confused here and obviously missed something.

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            • #21
              Originally posted by mschulz View Post
              Sunking, I think I have missed some lessons here and I hope you will help me catch up. With the IOTA, everything I read says it is a four stage charger. When they say it is a 30 amp converter / battery charger am I getting the full 30 amps to my battery. If not, the IOTA is useless to me except a way to convert my AC generator power to DC power.
              First what model are you talking about?

              The Iota DLS i snot what I would call a battery charger, its a regulated DC power supply which can be used as a battery charger. There is a very fine line between a battery charger and DC power supply. The difference lies in output filter capacitors to clean up the rectifiers. A DC supply will have good filtering giving you a nice clean steady state DC voltage that you can use to power Gizmos directly from and charge a battery if you want.

              For Iota its been a while but I have experience with the DLS series. The DLS is really a DC power supply that you can set the output voltage and have two options to convert to a charger. One is a plug and all it does is raise the voltage up from a Float Voltage of 13.6 volts to 14.something or Two Stages. They have a IQ-4 option that plugs into the same port as the other 2-stage plug, but gives you 3 or 4 stages. Perhaps they have changed the design to make it a True 4-stage charger.

              As for current, that depends on two factors: How much current the charger is capable of supplying, and the state of charge the battery is in with respect to the battery internal resistance. So th eIota model you are talking about has a limit of 30 amps. If you connect it to a discharge battery say 12.4 volts, and the charger is set for 13.6 volts, it will supply 30 amps until the battery voltage approaches 13.6 volts. At that point the current will begin to taper off toward 0 amps. When the current tapers off to roughly 3% of C, the battery is charged up.
              MSEE, PE

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              • #22
                Originally posted by Sunking View Post
                First what model are you talking about?

                Two Stages. They have a IQ-4 option that plugs into the same port as the other 2-stage plug, but gives you 3 or 4 stages. Perhaps they have changed the design to make it a True 4-stage charger.


                As for current, that depends on two factors: How much current the charger is capable of supplying, and the state of charge the battery is in with respect to the battery internal resistance. So th eIota model you are talking about has a limit of 30 amps. If you connect it to a discharge battery say 12.4 volts, and the charger is set for 13.6 volts, it will supply 30 amps until the battery voltage approaches 13.6 volts. At that point the current will begin to taper off toward 0 amps. When the current tapers off to roughly 3% of C, the battery is charged up.
                Yes, I have the DLS-30 with built in IQ4 which they say makes it a true 4 stage charger (Bulk =2.466V per cell; Absorb= 2.366V per Cell; Float= 2.266V per cell). As for what the charger pushes to my battery, your explanation is what I thought was happening, thank you for the clarification.

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                • #23
                  Originally posted by mschulz View Post
                  Yes, I have the DLS-30 with built in IQ4 which they say makes it a true 4 stage charger (Bulk =2.466V per cell; Absorb= 2.366V per Cell; Float= 2.266V per cell). As for what the charger pushes to my battery, your explanation is what I thought was happening, thank you for the clarification.
                  NP you are welcome.
                  MSEE, PE

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                  • #24
                    The Iota I have, is a simple DC supply. No smarts in it other than a trimpot. The IQ plg they sell, just modulates the output voltage, but I don't see how they can call it 4 stages (or even 2 w/o the IQ).

                    A pair of computer PSU units geared to 12V, would be better, the new ones have PF correction.
                    600w : +3.3V@22A, +5V@18A, +12V1@23A, +12V2@20A, -12V@0.3A, +5VSB@2.5A Thermaltake TR2 TR-600 600W

                    = 40A @ 12.01V, if you can fool the other voltages into staying in regulation. $50 US.
                    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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                    • #25
                      Originally posted by mschulz View Post
                      I looked at the Samlex chargers and their lititure states they have to charge with no load on the batteries. I am confused here and obviously missed something.
                      The reason for that is that with a load active, and you have the absorb setpoint at 14.4v, if the load is small enough, the batteries will eventually reach absorb, but never come out, as the load prevents the charger from seeing a falling current and triggering the switch to float. - so one could end up in an endless-absorb state. And that is if your gear can handle 14.4v.

                      What they recommend if you do that, is to use the 13.6v setting, which of course means that the battery should no longer be used in a cyclic-service, but one of standby. In this setting, yes you could run with a load easily, but you give up cycle-service from the battery.

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                      • #26
                        Originally posted by Mike90250 View Post
                        The Iota I have, is a simple DC supply. No smarts in it other than a trimpot. The IQ plg they sell,
                        That's the RJ-46 Jack right? That is what I recall. Reading the manual, they are not claiming 4-stage exactly. With the simple wire jumper it goes up 1 volt from Float. Use the IQ plug and I assume it does a pseudo 3-stage from the description of a higher voltage Bulk Absorb stage. Not real clear. Me thinks it just jacks up the voltage to a EQ level. Only difference between a Float Charge and EQ Charge is the voltage.
                        MSEE, PE

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                        • #27
                          Well, I finally ordered a standard Iota DLS-55. The powermax was interesting (and nicely priced) but I just couldn't find one at reasonable shipping costs...

                          Thank you all

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                          • #28
                            Testing IOTA DLS-30

                            I did a little field-testing and research this weekend with the IOTA DLS-30 with IQ4 installed internally. This is a 12 v 30amp Power converter / battery charger (Taken from Iota’s instruction manual).

                            The battery I used was a car battery that was about 2 years old, who knows what condition it really is in, my guess it that it is on its last legs. I used this battery because it was a FLA and I did not want to start experimenting with my new Trojan -31 AGM battery.

                            I installed two Ammeter and voltmeters to measure input and draw and calibrated them with my multi meter. I hooked up a 45 watt 12v solar panel to the system with a cheap, and I mean cheap Solar Force PWM Charge controller that I had laying around. For running the IOTA I used my Honda EU2000I. For my draw, I ran my Dometic CF50 cooler that draws 3 amps at 12volt.

                            I charged the battery at home with a car style 12 amp charger and had it on the trickle charger for 2 days.

                            I ran the fridge all day Saturday hooked up to the solar panel as I had full sun. I moved the solar panel as the sun moved and was able to gain 3-3.5 amps from solar. The fridge ran all night with its on an offs (normal use). Sunday morning the battery was at 11.5 volts and the fridge was off due to the automatic battery protection.

                            I started the generator and warmed it up and switched it to Eco mode. I plugged in the IOTA and there was a quick draw but then the generator went back to a low RPM.

                            IOTA Charging at a constant 14.1 Volts
                            26 AMPs for 10 minutes - Bulk
                            15 AMPS for 15 minutes- Bulk
                            9 AMPS for 90 minutes - Bulk
                            6.1 AMPS for 1 hour before I turned off the generator – Absorption

                            I never hit float on the IOTA. When a load was turned off or on AMPS and Volts did not waiver.

                            If you have suggestions for better testing or question please post them up. I am no expert and would love to have feedback.

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                            • #29
                              Originally posted by mschulz View Post
                              IOTA Charging at a constant 14.1 Volts
                              26 AMPs for 10 minutes - Bulk
                              15 AMPS for 15 minutes- Bulk
                              9 AMPS for 90 minutes - Bulk
                              6.1 AMPS for 1 hour before I turned off the generator – Absorption
                              OK something is wrong with this picture.

                              Bulk is a constant Current Mode, not Constant Voltage as you describe. There is no specified voltage during Bulk charge other than a Set Point to terminate the the Bulk stage at which point switches to Absorb. For example if Bulk is set to 14.1 volts on a 30 amp charger with a discharged battery what you would expect to see is the full 30 amps. Initially the voltage will be well below 14.1 volts, down in the 12 to 13 volt range with a steady 30 amps. As the battery charges, the voltage begins to rise but still 30 amps. Once the battery voltage reaches set point of say 14.1 volts, the charger switches to Absorb which is a Constant Voltage, current Taper.
                              MSEE, PE

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                              • #30
                                Originally posted by Sunking View Post
                                OK something is wrong with this picture.

                                Bulk is a constant Current Mode, not Constant Voltage as you describe. There is no specified voltage during Bulk charge other than a Set Point to terminate the the Bulk stage at which point switches to Absorb.....
                                It's easy to understand how 'mshultz' might be a bit unclear... look at this table from the Iota IQ4 manual:
                                iotaiq4.jpg
                                --mapmaker
                                ob 3524, FM60, ePanel, 4 L16, 4 x 235 watt panels

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