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  • Monitering the Batteries

    I have eight 6 volt GC batteries, two 24v banks, a Cotek 1500 watt inverter for emergency power and Im wondering what would be the best way to monitor the batteries, The house is 240 feet from the engine room so I would think I'll be hoofing it back and forth keeping a eye on things Any tips on what to get?

  • #2
    Both of my charge controllers, and my inverter report battery voltage, and I feed them into a wi-fi router and use my laptop to check up on things.
    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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    • #3
      Thanks for the reply, I wonder if your the same Mike (Mmmm BBQ) that helped me out over on the Lister forum. If so I took your advice and got a 3 kva balancing transformer, works like a charm. I figured if I need to run a Lister during an outage, might as well be charging some batteries and here I am involved in another project. I see by some of your links you have a pretty squared away off the grid system.

      As to monitoring batteries, I got a TriMetric 2030RV a with 500 amp shunt and 300 feet of Cat 5 DB cable.

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      • #4
        Originally posted by stevo View Post
        As to monitoring batteries, I got a TriMetric 2030RV a with 500 amp shunt and 300 feet of Cat 5 DB cable.
        You could have done it for less than $25. Fifteen dollars of that would have been cable.
        MSEE, PE

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        • #5
          Originally posted by Sunking View Post
          You could have done it for less than $25. Fifteen dollars of that would have been cable.
          I'll go for that, How?? In language a real newbe can digest and implement?

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          • #6
            Originally posted by stevo View Post
            I'll go for that, How?? In language a real newbe can digest and implement?
            A cheap 12 volt battery meter used in autos like this one.

            MSEE, PE

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            • #7
              Your saying that a $8.50 volt gauge would take the place of one of the Bogart devices? Why would anyone ever buy the Bogart device?

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              • #8
                Originally posted by stevo View Post
                Your saying that a $8.50 volt gauge would take the place of one of the Bogart devices?
                No not exactly. The Bogart or any other battery monitor has some processing power mostly in the form of a Coulomb Counter (Amp Hours) which is about worthless with Lead Acid Batteries due to Peukert Law, charge/discharge rates, temps, and aging. Some Monitors even have some Control circuitry that can be programmed by the user. But any cheap voltmeter can read voltage and be used to determine SOC just as well as any monitor. Difference is the monitor translates voltage to SOC percentage electronically. A voltmeter requires the user to use a protein computer to translate voltage to SOC using a chart or memory. Question is How Much Are You Willing To Pay?


                Originally posted by stevo View Post
                Why would anyone ever by the Bogart device?
                Why did people vote for Obama? Because they will believe anything despite facts. This goes back to my original statement you want an Idiot Light. There are many ways to achieve that. One is the very expensive way buying a battery monitor. It works. But so does a simple volt meter.

                Look battery monitors have some usefulness. They can tell you accurately how many Amp Hours you use in a specified times. They can also tell you how many Amp Hours are pumped into a battery. But at the end of the day, the info is far from accurate and requires weekly calibration. The only true real time battery SOC meter is a cheap Temperature Compensating Battery Hydrometer.

                Where battery monitors do come in handy and fairly accurate is with a battery that has a 100% or near 100% Charge Efficiency. Just off the top of my head the Lithium family of batteries are the only batteries near enough 100% charge efficient assuming less than or equal to 1C rates. This is particularly useful with EV's or other critical systems where you must know the remaining charge left. No voltage meter can tell you that. Lead Acid, NiCd, NiFe etc are all chemical reaction batteries and efficiency is fair to poor and unpredictable. Lithium is an Ion Exchange and comes as close to 100% charge efficient as you can get. Warning here Charge Efficiency does not EQUAL Power Efficiency. Charge Efficiency is a measure of Amp Hours In vs Amp Hours Out. Amp Hours goes in at higher voltage than coming out. All batteries are less than 100% Power Efficient, including Lithium.

                Only time voltage is anywhere near close to the true SOC is on a well rested battery. But even then tells you nothing about capacity. All you want to know is Go or No Go, an Idiot Light. All you are looking for is a voltage under load that tells you things are OK or Shut Down right? Assuming you are operating a 12 volt lead acid battery that magic number under load is 11.90 volts under full load, or 12.10 volts at rest. for 24 volts double the numbers.

                I am not saying the Bogart will not work for you and do what you want because it will do that. Al I am saying there is another way to get what you want at a fraction of the cost. It is a DUMB METER, you have to provide the SMARTS and CONTROL. The Bogart is the same thing plus some Smarts and Controls someone else decided.

                You biggest worry is over discharging your battery. That is why Inverters have Low Voltage Shut Down. Unfortunately low end Inverters are factory set at 10.5 to 11 volts which is a bit too low. The higher end Inverters allow the operator to set LVD, and 11 to 12.1 volts is the range one is looking for to fully protect their batteries.
                MSEE, PE

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                • #9
                  Thank you for the clarification, that makes sense. Simple is better. I did follow your suggestion of going with a 24volt system instead 12v. Would you happen too know what size wire I would need for a 240 foot run for that volt meter? I'm thinking maybe I could use the Cat 5 wire, two pairs on each conductor (2) of that volt meter.

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                  • #10
                    Originally posted by stevo View Post
                    Would you happen too know what size wire I would need for a 240 foot run for that volt meter? I'm thinking maybe I could use the Cat 5 wire, two pairs on each conductor (2) of that volt meter.
                    That is the beauty of it as almost no current is required, so a single pair of CAT X (Any Number) is over kill. CAT 5 or higher is a good choice as the winding will help eliminate and control noise errors. Personally I would use a shielded cable, and bond the shield at the battery end only. I would also use a good ole fashion salvaged Carbon Telephone Block protector or even gas tubes. Or if you can find and buy cheap MOV's for a 25-cents each would also work great and you would need 3 of them. T-R, T-G, and R-G modes using a plain ole RJ-11 telephone wire jack.

                    MSEE, PE

                    Comment


                    • #11
                      Originally posted by Sunking View Post
                      That is the beauty of it as almost no current is required, so a single pair of CAT X (Any Number) is over kill. CAT 5 or higher is a good choice as the winding will help eliminate and control noise errors. Personally I would use a shielded cable, and bond the shield at the battery end only. I would also use a good ole fashion salvaged Carbon Telephone Block protector or even gas tubes. Or if you can find and buy cheap MOV's for a 25-cents each would also work great and you would need 3 of them. T-R, T-G, and R-G modes using a plain ole RJ-11 telephone wire jack.

                      Outstanding, thanks, I can run the CAT 5 wire and use it for either device should I decide to keep the Bogart. You haven't solved my problem of still having to get out there and dig a ditch tho

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                      • #12
                        Originally posted by stevo View Post
                        You haven't solved my problem of still having to get out there and dig a ditch tho
                        That is what Slaves are for. Excuse me I meant your kids or grand kids.
                        MSEE, PE

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                        • #13
                          Originally posted by stevo View Post
                          Thanks for the reply, I wonder if your the same Mike (Mmmm BBQ) that helped me out over on the Lister forum. .......
                          Yep. guilty as charged.
                          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
                            I cant imagine putting these systems together without the help of the kind folks of these forums, Thanks you-all

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                            • #15
                              A good battery condition meter will allow you to program in the basic Coulombic efficiency of the type of battery you use. Then at least you are in the right ball park.
                              Unfortunately, as Sunking implies, Peukert's Law tells us that for Lead Acid the Coulombic efficiency also varies with charge and discharge rate, and I am not aware of any battery monitor that gets that sophisticated.
                              SunnyBoy 3000 US, 18 BP Solar 175B panels.

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