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solar novice off grid.... perpetual battery problems

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  • solar novice off grid.... perpetual battery problems

    Hi everyone, I'm new to this forum and a relative novice with solar. I live off grid. Not a great demand on electricity... 120w fridge freezer, 2 40w fans, phone charging and lights.
    Im in west Africa and system electricians are not particularly good. I'm on my third battery bank in 5 years... And it's going to bankrupt me at this rate.
    Currently have 2x 260w Riter batteries, 6 weeks old.6 x250 panels, 3kw victron Inverter and an optisolar 60 charge controller. This hasreplaced 6x180w batteries (which went into meltdown at 18months) 12 250w panels, 2 charge controllers and victron inverter.
    I will replace the larger system if I ever get it right.
    Problems I Have right now is I'm not getting above35 Amps from the 6 panels. Cloudy or sunny makes no difference. As soon as controller goes from fast to boost charge batteries are getting very warm. I have a fan on them to keep temperature around or below 28degrees.
    On a sunny day, even one cloud will cause a substantial drop in shown voltage when on boost. Rarely gets into float.
    Any advice greatly appreciated. X

  • #2
    You are describing gear with local brands (the batteries) Can you tell us
    system voltage - 12, 24 or 48V
    Type (flooded, AGM)?
    Amp Hour rating @ 20 hr
    wired how, 8 in series to get 48V 3 strings of the 8 batteries

    (these numbers are on stickers on backside of panel and on spec sheet)

    But I can see from your panels, being only 1600W (just like the car with a 35mpg sticker gets 22mpg in real life) and a 3kw inverter (which will suck a lot of power just sitting doing nothing)

    Is there ANY shade or debris on the panels. Even the shade from a twig or a pencil is enough to severely restrict the panel output. If the panels are not well matched electrically, they will have reduced power.

    at 12V , you could expect 130A, needing 3 charge controllers, 24V needs 70a of controller, and 48V needs 33a of controller

    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



    • #3
      OK thanks. I will try and answer the best I can.
      This temporary system is 2 260amp at 10 hour. 12v wired to 24v . They are sealed lead acid.

      Panels are 250w 24v.
      I have no idea if they are wired in series or parallel. I really am a novice... But need and want to learn. I will find out from solar electrician.
      There is a little bit of shade in a morning but after 10 am it's absolutely clear till about 6pm.

      I will Just make a phone call and try and find out some more... And check the labels on the stored panels

      Best wishes


      • #4
        Originally posted by kadi View Post
        I'm on my third battery bank in 5 years...
        Not sure that is a problem and would be expected using AGM batteries of unknown quality

        Originally posted by kadi View Post
        .6 x250 panels .... Problems I Have right now is I'm not getting above35 Amps from the 6 panels.
        That may or may not be a problem and would depend on the battery voltage you are running. If designed properly would be 48 volts and with 35 amps of current is close to 1500 watts. If operating at 24 volts is half power or 750 watts which tells you exactly what the problem is. It is SCREAMING AT YOU.
        MSEE, PE


        • #5
          I am trying to understand this. It seems he has 2 x 12V 260Ah (AGM?) batteries in series for 24V, probably a PWM 60A (Optisolar SC 60) controller and 6 x 24V, 250W panels which would therefore have to be wired in parallel. Guess he is hoping to get about 10A from each panel for about 60A but is only getting 35A max. Wouldn't 35A be giving him close to a C7 charge rate?


          • #6
            SunKing....thanks for the reply. We have a few problems getting good equipment here. I have just heard there are good 6v batteries around but at almost ....sorry my post has vanished. Let me start again.
            Last edited by kadi; 10-01-2018, 11:34 AM.