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  • Help with batttery system

    Greetings. I have been trying to gain a little knowledge and set up a battery system, without panels, at least for now. I'm on the grid and use this system during power outages. I understand that using four 225 amp in series for a 24v system would be better, although way more spendy, than a 12v system. I have a 2.9 KW gen head powered by a 4&1/4 HP Lister SL1 and a 5KW ST head powered by a 8.5 HP Lister SL2. Only one gen set at a time can be run, Not allot of power. I'm aware that I need a good 120v three stage 24v, charger but I don't want to put allot of strain on the gen set if I need to charge the bank before grid power is back up. I'll need to run the them for the well pump, shop tools etc when needed, every tow or three days+-...I am considering a 24v 1000 watt Go Power inverter to send the power to the six circuit transfer switch in the house. My needs in the house dont amount to 700 watts with all the lights TVs, DVRs computers and both small reefers all running, checked everything with my "watts up" meter. So considering the small gen sets and the fact that "run time" really isn't an issue, what 24v charger would be a good choice. I dont quite understand figuring out amps and time required for charging and how that relates to battery health. I am grateful for the help I've already gotten, as was told to me "ask questions first"

  • #2
    Are you able to afford a GOOD charger, or do you have to just get by ?
    The larger inverters can also be used as chargers from the generator, I know the XW series does this (that's what I use) and I think outback can do it too.

    Stand along chargers, Iota has solid ones, but they have poor power factor.
    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


    • #3
      Let's get some simple math out of the way and help you understand. It is 5th grade math and super easy

      Starting with Amp Hours = Amps x Hours. Told you it was hard.

      From that equation then you know:

      Amps = Amp Hours / Hours
      Hours = Amp Hours / Amps

      Using simple numbers let's say you have a 100 AH battery. You want to discharge it at 10 amps. How many hours does it take to discharge it. 100 AH / 10 A = 10 Hours.

      Want to charge that battery from completely discharged with a 10 amp charger. How many hours will it take. 100 AH / 10 A = 10 Hours.

      How many Amps can that same battery last with a 5 Hours discharge rate? 100 AH / 5 H = 20 Amps

      Unfortunately life is not that simple. Batteries are not 100% efficient and Mr Peukert Law gets in the way. Not to worry what is above gets you the idea.

      Next problem you run into is batteries have minimum and maximum charge rates. A FLA battery minimum is C/12 and maximum is C/8 generically. C = the battery AH capacity at the 20 Hour discharge rate. So those 225 AH batteries need at least a 225 AH / 12 H = 18.75 amps. Just call it 15 is close enough. The maximum is 225 AH / 8 H = 28.125 amps. Just call it 30 amps is close enough. So you now know you need something in the 15 to 30 amps. But there is a Gotcha. It you go with 15 and want to use power while charging, you are robbing the battery of charge current. If your load is 30 amps and you have a 15 amp charger, you are still discharging your battery at 15 amps. Gotcha!

      On the Flip Side Batteries have a Maximum Discharge current they can provide otherwise their voltage will sag to far and cause unnecessary Low Voltage Disconnect built into all Inverters. For standard FLA battery that is about C/8 or 30 amps on a 225 AH battery. So if your limit is 30 amps limits how large of an Inverter you can run. So you want to run 24 volts x 30 amps = 720 watts. Not a good match for a 1000 watt Inverter.

      Don't cuss there is a work around. Use a hybrid FLA or a more expensive AGM battery. Buy Golf Cart FLA batteries, as they are Hybrids. A Golf Cart battery can handle C/4 Discharge currents so a 225 AH battery can supply up to 225 / 4 = 56.25 amps, just call it 60 amps. At 24 volts x 60 amps can handle a 1500 watt Inverter so a 1000 watt 24 volt Inverter is no problem.

      This brings us back to a battery charger issue again. You do not need a 3-Stage Battery Charger for Emergency Back Up. You do not even want one for that application. You want a FLOAT CHARGER of the appropriate Amperage Capacity. You will leave it plugged into commercial AC keeping the batteries fully charged waiting to be used. You want it to be as large as a standard 120 VAC wall socket can supply and your generator. a 120 VAC circuit in your home can supply 1500 watts continuously. So for a 24 volt battery charger you are looking at a 60 Amp 24 volt charger.

      Now just go over what we just did and look at how the pieces fit together in harmony.

      You are looking at needing a:

      1800 watt genny. check
      24 volt 60 amps FLOAT CHARGER. Check
      4- 6 volt 225 AH Golf Cart Batteries wired in series. Check
      1000 Watt TSW Inverter. Check

      Fits like a custom tailored shirt made with Warm Fuzzy.
      MSEE, PE

      Comment


      • #4
        A goggle search turned up this at Amazon, MorningStar TriStar TS-60 Amp Solar Battery Charge Controllerits, $572 Yikes, This project is spiraling outa control but I think I'll carry on because panels may be added later. If I had to bring the batteries back to full charge with my "big" 5KW, generator that might be a problem?

        edit, Oh, I see your 1800 watt for the gen set. Do these chargers put out max amps at first then drop off easing the load on the jenny? and if I did get a few panels they would be hooked up to this charger, max 3KW? I'm trying to justify the $ Thanks again for the help.

        Comment


        • #5
          Originally posted by stevo View Post
          A goggle search turned up this at Amazon, MorningStar TriStar TS-60 Amp Solar Battery Charge Controllerits, $572 Yikes,
          Lot cheaper than PWM. With PWM you are forced to use very expensive battery panels costing $2 to $6 per watt. With MPPT you can use higher voltage Grid Tied panels costing $1 per watt. It takes a 300 watt PWM system to equal a 200 watt MPPT system. A 300 watt PWM system is going to cost you roughly $600 to $700. A 200 watt MPT System roughly $400 to $450.

          $572 is too much for a 60 amp controler. Top of the line is Midnite Solar Classic 150 is a 90 to 96 amp controller for $600.

          Originally posted by stevo View Post
          If I had to bring the batteries back to full charge with my "big" 5KW, generator that might be a problem?
          How did you come to that conclusion? A 60 amp 24 volt charger would need a 1.8 to 2 Kw generator. To get the most out of your fuel you want to run your genny up around 70 to 80% fully loaded. Running 30% is going to burn up a lot of fuel.
          MSEE, PE

          Comment


          • #6
            Originally posted by Sunking View Post
            Lot cheaper than PWM. With PWM you are forced to use very expensive battery panels costing $2 to $6 per watt. With MPPT you can use higher voltage Grid Tied panels costing $1 per watt. It takes a 300 watt PWM system to equal a 200 watt MPPT system. A 300 watt PWM system is going to cost you roughly $600 to $700. A 200 watt MPT System roughly $400 to $450.

            That same Morning Star 60 amp controler is $516 at Ebay. So just to clarify..I can charge batteries with grid power or jenny with this type of device and it will also handle power coming in from panels? Would you recommend anything besides the Midnite Solar Classic, which was more like $800 where I looked. As to the jenny question overload question, I hadn't seen your 1800 watt comment, no problem

            $572 is too much for a 60 amp controler. Top of the line is Midnite Solar Classic 150 is a 90 to 96 amp controller for $600.

            How did you come to that conclusion? A 60 amp 24 volt charger would need a 1.8 to 2 Kw generator. To get the most out of your fuel you want to run your genny up around 70 to 80% fully loaded. Running 30% is going to burn up a lot of fuel.
            Most of the time when I'm running my 2.9 KW jenny, I only need 5or 600 watts, I could be running off batteries then when I need water or shop tools, I light off the bigger jenny and charge batteries along with the other bigger loads even if I cant run everything at once.

            Comment


            • #7
              Originally posted by stevo View Post
              Most of the time when I'm running my 2.9 KW jenny, I only need 5or 600 watts, I could be running off batteries then when I need water or shop tools, I light off the bigger jenny and charge batteries along with the other bigger loads even if I cant run everything at once.
              No problem Steve, i twill work. I just want to make sure you understand what you are doing and giving up.
              MSEE, PE

              Comment


              • #8
                Found this at Amazon... "Progressive Dynamics (PD9260CV) 60 Amp Power Converter with Charge Wizard.... Its $200, seems too cheap to be true. Could this possibly be any good??

                Comment


                • #9
                  Originally posted by stevo View Post
                  Found this at Amazon... "Progressive Dynamics (PD9260CV) 60 Amp Power Converter with Charge Wizard.... Its $200, seems too cheap to be true. Could this possibly be any good??
                  Do you see UL Listing in the specs? If not, look no further, move on.
                  SunnyBoy 3000 US, 18 BP Solar 175B panels.

                  Comment


                  • #10
                    Originally posted by stevo View Post
                    Found this at Amazon... "Progressive Dynamics (PD9260CV) 60 Amp Power Converter with Charge Wizard.... Its $200, seems too cheap to be true.
                    It would work. I know the name Progressive Dynamics. They make electrical power systems for the RV market in Canada and USA. They are UL listed and tested.

                    Is this it?

                    If so you do know that is 12 volts right? I thought were were discussing 24 volts?

                    Here are some for Marine apps
                    Another one
                    MSEE, PE

                    Comment


                    • #11
                      Originally posted by Sunking View Post
                      Let's get some simple math out of the way and help you understand. It is 5th grade math and super easy

                      Starting with Amp Hours = Amps x Hours. Told you it was hard.

                      From that equation then you know:

                      Amps = Amp Hours / Hours
                      Hours = Amp Hours / Amps

                      Using simple numbers let's say you have a 100 AH battery. You want to discharge it at 10 amps. How many hours does it take to discharge it. 100 AH / 10 A = 10 Hours.

                      Want to charge that battery from completely discharged with a 10 amp charger. How many hours will it take. 100 AH / 10 A = 10 Hours.

                      How many Amps can that same battery last with a 5 Hours discharge rate? 100 AH / 5 H = 20 Amps

                      Unfortunately life is not that simple. Batteries are not 100% efficient and Mr Peukert Law gets in the way. Not to worry what is above gets you the idea.

                      Next problem you run into is batteries have minimum and maximum charge rates. A FLA battery minimum is C/12 and maximum is C/8 generically. C = the battery AH capacity at the 20 Hour discharge rate. So those 225 AH batteries need at least a 225 AH / 12 H = 18.75 amps. Just call it 15 is close enough. The maximum is 225 AH / 8 H = 28.125 amps. Just call it 30 amps is close enough. So you now know you need something in the 15 to 30 amps. But there is a Gotcha. It you go with 15 and want to use power while charging, you are robbing the battery of charge current. If your load is 30 amps and you have a 15 amp charger, you are still discharging your battery at 15 amps. Gotcha!

                      On the Flip Side Batteries have a Maximum Discharge current they can provide otherwise their voltage will sag to far and cause unnecessary Low Voltage Disconnect built into all Inverters. For standard FLA battery that is about C/8 or 30 amps on a 225 AH battery. So if your limit is 30 amps limits how large of an Inverter you can run. So you want to run 24 volts x 30 amps = 720 watts. Not a good match for a 1000 watt Inverter.

                      Don't cuss there is a work around. Use a hybrid FLA or a more expensive AGM battery. Buy Golf Cart FLA batteries, as they are Hybrids. A Golf Cart battery can handle C/4 Discharge currents so a 225 AH battery can supply up to 225 / 4 = 56.25 amps, just call it 60 amps. At 24 volts x 60 amps can handle a 1500 watt Inverter so a 1000 watt 24 volt Inverter is no problem.

                      This brings us back to a battery charger issue again. You do not need a 3-Stage Battery Charger for Emergency Back Up. You do not even want one for that application. You want a FLOAT CHARGER of the appropriate Amperage Capacity. You will leave it plugged into commercial AC keeping the batteries fully charged waiting to be used. You want it to be as large as a standard 120 VAC wall socket can supply and your generator. a 120 VAC circuit in your home can supply 1500 watts continuously. So for a 24 volt battery charger you are looking at a 60 Amp 24 volt charger.

                      Now just go over what we just did and look at how the pieces fit together in harmony.

                      You are looking at needing a:

                      1800 watt genny. check
                      24 volt 60 amps FLOAT CHARGER. Check
                      4- 6 volt 225 AH Golf Cart Batteries wired in series. Check
                      1000 Watt TSW Inverter. Check

                      Fits like a custom tailored shirt made with Warm Fuzzy.
                      Thanks for the clear tutorial! If I might ask a question. How does the float-only charger give a maximum charge to the battery after it has been discharged? Would'nt a three stage charger be better for that?

                      Comment


                      • #12
                        Nope, don't see any UL Listing, the search continues I guess.

                        Comment


                        • #13
                          Originally posted by lkruper View Post
                          Thanks for the clear tutorial! If I might ask a question. How does the float-only charger give a maximum charge to the battery after it has been discharged? Would'nt a three stage charger be better for that?
                          Looking at the prices of 24v 60 amp three stage chargers and 1000 watt 24v inverters, maybe I need to back up the power train and go with two golf cart batteries a 500 watt 12v inverter and battery charger, that system would provide enough for lights & TV for a couple days then it would be time to pump water with the jenny, at which time the batteries could be charged with an affordable 12v charger. I also don't understand how the batteries would be recharged with a float charger if they were flat and the grid was still down.

                          Comment


                          • #14
                            Originally posted by stevo View Post
                            Looking at the prices of 24v 60 amp three stage chargers and 1000 watt 24v inverters, maybe I need to back up the power train and go with two golf cart batteries a 500 watt 12v inverter and battery charger, that system would provide enough for lights & TV for a couple days then it would be time to pump water with the jenny, at which time the batteries could be charged with an affordable 12v charger. I also don't understand how the batteries would be recharged with a float charger if they were flat and the grid was still down.
                            I'd get a IOTA DSL-30, charger / power supply, 12 v and the separate IQ4 plug in module and it'd have 3 stage and charge up two GC-2's pretty quick, I think the DLS-45 amp would be a little on the big side, but would also work. it's all you need for a system like yours.

                            Comment


                            • #15
                              Originally posted by stevo View Post
                              Looking at the prices of 24v 60 amp three stage chargers and 1000 watt 24v inverters, maybe I need to back up the power train and go with two golf cart batteries a 500 watt 12v inverter and battery charger, that system would provide enough for lights & TV for a couple days then it would be time to pump water with the jenny, at which time the batteries could be charged with an affordable 12v charger. I also don't understand how the batteries would be recharged with a float charger if they were flat and the grid was still down.
                              I have been going over this exercise for my grid-connected cabin just in case there is a power outage. I got a kill-o-watt meter to measure what I am using and starting looking at my devices to see what they pull. I discovered that my very nice 32" Sony HDTV pulls 142 watts (still need to measure actual). I found a 32" Samsung commonly sold at Target/Walmart, etc that is said to pull 28w and also works on both AC and DC. The difference is huge.

                              I have been going over all the options for batteries, chargers, solar, etc and think my first move will be to utilize a 2KW inverter generator that I already own and also consider getting a manual transfer switch. I just put in an APC UPS to handle my DSL modem. I am considering the APC 1500 with extra battery pack for a combined total for the entertainment from Amazon which looks like for about $300 I can get about 4 hrs.

                              This will take the vast majority of power outages (I have fireplace, oil lamps, camping stoves, etc ) while I plan for El Nino this summer and potential floods which could affect power.

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