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  • Installing a solar charging system in parallel to grid

    I have loads running on 230V, 50Hz AC at my residence. In case of power failure from the utility, i have a back up with a 135 Ah Lead Acid battery along with a 800VA UPS which switches on almost instantly. On resumption of supply from the utility, the battery gets charged. Now i am planning to install a solar panel and connect the output from the solar panels (DC) to the battery for battery charging. This charging will be in parallel to the normal charging available from the UPS (utility AC supply). The preference of charging will be of the solar supply. Another question is that is there any method available that i can charge my battery along with the supply of the loads.
    I am trying for this alternative because here we have 2 hours of supply from the utility followed by 4 hours of power cuts in desperate summers.
    Last edited by abishekmittal; 08-18-2009, 01:44 PM. Reason: clear email address

  • #2
    1) please don't post your email in a message, keep it in your profile, where it is 2 steps away from spambot harvesting

    2) You need to manage your loads. Keep only critical loads on the UPS

    3) determine the battery capacity of the UPS, and it's internal charger - how fast does the interna charger, recharge. You dont want to hook another charger in parallel and smoke the battery with too much current.

    3b) Is the battery AGM or GEL - BIG difference in recharge profile.

    4) can your UPS support longer run times, some have no provision for cooling, and are designed to not overheat by the time the batterys expire. If you extend the run time, you could burn the inverter.

    When you know the voltage and current you can safely supply into the batteries, post it, and we'll help more.

    Do you knw what 1,000W of PV panels will cost you in your area, and do you have a safe/secure place to mount them ? Can you afford them ?
    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
      Originally posted by Mike90250 View Post
      1) please don't post your email in a message, keep it in your profile, where it is 2 steps away from spambot harvesting

      2) You need to manage your loads. Keep only critical loads on the UPS

      3) determine the battery capacity of the UPS, and it's internal charger - how fast does the interna charger, recharge. You dont want to hook another charger in parallel and smoke the battery with too much current.

      3b) Is the battery AGM or GEL - BIG difference in recharge profile.

      4) can your UPS support longer run times, some have no provision for cooling, and are designed to not overheat by the time the batterys expire. If you extend the run time, you could burn the inverter.

      When you know the voltage and current you can safely supply into the batteries, post it, and we'll help more.

      Do you knw what 1,000W of PV panels will cost you in your area, and do you have a safe/secure place to mount them ? Can you afford them ?
      Thanks for your prompt reply.
      1. First of all my battery is flooded tubular type lead acid battery (12V), 150 Ah.

      2. I already have only critical loads on my UPS as there is a separate circuitry for the UPS loads in the residence.

      3. As far as my UPS is concerned, i am using a Microtek 800VA UPS which is 24x7 connected to the battery and AC supply. So, i don't feel there is concept of overcharging/overheating as the cutoff function is inbuilt in the unit.

      Battery : 1 Battery System
      Input DC Range : 10.5 ~ 14.2
      Efficiency (on battery mode) : >84%
      Charger Current : 9.0 A
      UPS Transfer Time : ≤ 15 msec.
      Switching from Mains to UPS and from UPS to Mains : Automatic
      Last edited by abishekmittal; 08-18-2009, 02:12 PM.

      Comment


      • #4
        "Flooded tubular" That's a new one. I'll assume it has battery caps you periodically remove to add distilled water to. (flooded)

        I'll also assume that the system cuts off at about 70% discharged, as UPS is not supposed to see a lot of activity, and will have few cycles over it's lifetime.

        150AH flooded can accept a C/8 ( capacity / 8 ) so your case, max current would be
        http://www.windsun.com/Batteries/Battery_FAQ.htm
        150/8 = 19A. Subtract the 9A internal charger, you can safely add a 10A charger, without
        damaging your battery. (If you battery is sealed, and you cannot add water, you likely have a Gel. Sealed batteries should charge at C/20 or 5% of their capacity: 7.5A)

        So 2 hours will not see a full charge into a deeply discharged battery.

        You could look into a replacement battery, that can take a very high recharge current:
        Concorde AGM. They maybe tough to find, but they can take a very hi recharge for the
        major part of the recharge cycle.
        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
          Ya, you got the right info. I have to add water in it periodically (after every 3 months). I am not sure whether the system cuts off at 70% but the UPS sees a of activity as the battery always gets discharged as there are frequent power outages for long durations. I am not worried for the charge time of 2 hours. My main requirement is the paralleling of the solar system along with the normal running system.

          Comment


          • #6
            Welcome abishekmittal, thanks for joining Solar Panel Talk to ask your question.

            I'm moving your thread to the technical sub-forum for others to see. This welcome forum doesn't get as many views

            Comment


            • #7
              System grounding is also necessary.
              Many grid-connected solar arrays produce over 400 volts, so any electrical short to frame could actually electrocute someone, or the electrical short could arc and cause an electrical fire. Smaller 12-volt DC solar systems like this and designed for boat, RV, or camping applications do not usually include this added safety device due to the much lower voltage, and I cannot recommend leaving it out of your solar array wiring. However, if you decide your small solar array has very limited safety risk, it is still important to provide a good array ground to reduce the risk of lightning damage since you are bolting large metal objects high up on a roof in an open area.

              Comment


              • #8
                Mike I found this about Concorde. http://www.solar4power.com/solar-power-concorde.html

                Comment


                • #9
                  Hello Mr. Abhishek,

                  Let me know ur location. And do u have charge controller and SPV panels?

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