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  • I am keen to know what I am doing wrong ?

    Hi - I would like some advice as to what I have done wrong

    I have 2 of 200 watt panels on the roof running to a 50 amp PWM controller - joined in parallel at the panels and 2 of 2.5 mm2 running from there to the controller

    the controller feeds 2 of 120AH AGM batteries that are in parallel connected to gether with 2 of 2.5 mm2 wiring

    this feeds a 2000 watt 220VAC inverter





    Solar setup IMG_20180109_162839.jpg

    into one of the 220 VAC plugs I run a lead to a electro/mechanical timer switch for a 10 watt and 12 watt LED spotlight set to run for about 10 hours of darkness

    it has never run the whole time and I end up with a low battery alarm from the inverter

    I recently - 3 days ago - changed the controller charge off to 14.8 volts after looking at the batteries - this is after 6 months of the system running at I think 13.5 volts charge off which was the default setting but this does not seem to have helped.

    when the sun goes down and no more amps are charging the battery settles at about 12.8 volts and then under the LED spotlight load in will come down to 12.5 - 6 and then down to 11.2 volts over night until the alarm comes from the inverter and I switch off the inverter . - between 02h30 and 03h30

    now with the setting of the voltage off to 14.8 volts it actually seems to only last until 1h30 or 2h00 in the morning

    with good sun I am getting 10 amps charging and the batter is getting close to 14.8 volts whereupon the charging light flickers and the current reading in varies

    Solar setup IMG_20180109_162924_BURST1.jpg

    solar setup IMG_20180110_103249.jpg

    solar setup IMG_20180109_162901.jpg

    I am thinking I might change the cable to maybe 2 of 4mm2 for each lead and leg , but I wonder if I have damaged my batteries by running them for 6 months at less than 14.8 volts for charge off ?

    the other issue to maybe consider is that after the cyclone ( Ava - east coast Madagascar ) came through last Friday , I have been without mains power so have been using the inverter during the day to charge laptop , phones and battery lights

    but at the end of the day the battery is showing 14.5 volts

    yesterday the charge totalizer on the controller showed only 16 AH charge for the day ( it was a little overcast during the day and the max I saw was 6 amps charging ) , but so far today after 6 hours I have 10 AH

    any advice is appreciated
    thanks

  • #2
    First thing I notice is you mention you are running 2-200 watt panels into a PWM controller. What is the Vmp of these panels? Unless they are 12 volt nominal panels, approx. 18 volts at Vmp. you are losing a lot of potential power. You would need a real MPPT controller to get this power. Don't buy the cheapest MPPT controller you see as it will likely be fake. You should see in the stats a Voc. limit of either 100 or 150 Voc. Get back to us with your panels ratings for further recommendations.
    Next, your batteries may be damaged. Your tiny wires connecting them has to change and while parallel wiring batteries isn't the best way to set up a battery bank you should at the very least diagonally connect your CC and inverter. Connect the positive cables to one of the batteries and connect the negative cables to the OTHER battery. The charging stats are right on the batteries. At this point you should use the highest recommended voltage to charge your bank. If in fact your batteries are shot you should get two 6 volt deep cycle batteries and series wire them for 12 volts.
    2.2kw Suntech mono, Classic 200, NEW Trace SW4024

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    • #3
      Originally posted by smeee222 View Post
      Hi - I would like some advice as to what I have done wrong

      I have 2 of 200 watt panels on the roof running to a 50 amp PWM controller - joined in parallel at the panels and 2 of 2.5 mm2 running from there to the controller

      the controller feeds 2 of 120AH AGM batteries that are in parallel connected to gether with 2 of 2.5 mm2 wiring

      when the sun goes down and no more amps are charging the battery settles at about 12.8 volts and then under the LED spotlight load in will come down to 12.5 - 6 and then down to 11.2 volts over night until the alarm comes from the inverter and I switch off the inverter . - between 02h30 and 03h30
      I know exactly what is wrong and you are not going to like it.

      As of now your batteries are Boat Anchors. Real easy to determine by your own description. You get very low charge amps during the day, but yet the battery voltage goes up to 14 volts. Then when charging stops, and you apply a very light load completely drains the batteries in a few hours. Classic description of a sulfated battery. They are not taking a charge or giving a charge. Your batteries are toast.

      However before you run out an buy batteries you have a lot more problems to fix. First up is throw the charge controller you have away. Buy a good MPPT Charge Controller. Your PWM controller is not compatible with your panels. It turns 400 watts into 100 watts and is why you only see 10 amps thankfully. Get at least a 40 amp MPPT controller and wire your panels in series.

      Lastly your wiring skills need a lot of work. Case in point I direct the Jury's attention to your batteries. Note the wiring between the batteries looks like telephone wire. Way undersized and SLOPPY

      Next item up is absolutely no fuses or breakers. At least your wires are way undersized and will act like a fuse if you have a short or any real load. With 200 amps on a way over sized 2000 watt Invereter, if you ever put a 2000 watt load, your wiring will melt and act like a fuse.

      Wiring from panels to controller, and Controller to Battery should be 3 mm (5.5 mm2). Battery to Inverter and the Battery Interconnect should be 10 mm (54 mm2).

      You got yourself a fire trap. Be glad your batteries are dead, and your panels cannot produce full power. Otherwise you would burn the wiring up.
      Last edited by Sunking; 01-10-2018, 10:50 PM.
      MSEE, PE

      Comment


      • #4
        What is the wattage of your spotlight ? I doubt you need a 2Kw inverter to power it. I suspect your internal inverter losses are several times over what the spotlight consumes.
        Is your timer electronic with LCD display, or mechanical with a rotary dial ? If mechanical, you need to have a pure sine inverter. or the motor is going to eventually overheat and fail prematurely.

        I'd suggest along with the previous suggestions, to look at an efficient pure sine inverter, something like the Morningstar SureSine 300w inverter (avaib in 220V model) At least compare the power specs of the Suresine to other inverters to locate a low self-comsumption, efficient inverter
        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


        • #5
          thanks for the comments

          unfortunately my location - madagascar - does not give me access to parts like the first world , nor tradesman who understand wiring codes

          I will look to see if there are any MPPT controllers available , fix the wiring to a larger cross sectional area , and try and source some new batteries which I can be sure are in good condition when I buy them - is there anyway to recondition batteries that have sulphated ?

          thanks

          Comment


          • #6
            Originally posted by smeee222 View Post
            ..... is there anyway to recondition batteries that have sulphated ?thanks
            Exchange them for the recycle payment (core charge) when you purchase new ones. (about $5-10 us, each battery)
            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

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