not getting enough watts from solar panel

solarpowernovice
solarpowernovice Solar Expert Posts: 134 ✭✭
I have one solarworld 270 watt solar panel hooked up with 40 feet of #10 awg cable and I am only seeing 190 watts on the midnite classic display. The solar panels specs are 39.2V Voc 9.44A Isc, it is in full sunlight laying flat and it is noon... is my wire run too long or is it something else?

these are the cables i bought http://www.solar-electric.com/30fomc4so2ex.html but the wire is a silver color not copper...

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: not getting enough watts from solar panel

    There are two main factors that affect a solar panel's output: insolation and load. People tend to ignore that second one. It will not put out full power (do not expect 270 Watts; more like 207 on average) unless it is fully illuminated and fully loaded. The closer the battery is to charged the less power you get (unless you turn on all the loads). So how low is the battery?
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: not getting enough watts from solar panel

    BTW Isc and Voc are irrelevant to power output.
    Watts = Imp * Vmp. In this case I would hazard 8.7 & 31.
    Nor does that mean you will see that on the controller's display, as it will pick its own best power point which is not necessarily the panel specs.
  • solarpowernovice
    solarpowernovice Solar Expert Posts: 134 ✭✭
    Re: not getting enough watts from solar panel

    the batteries were at 12.5v when i started charging them ( around 10 am )and this is 75% state of charge according to the manufacturers website. I have four 232 amp hour 6v batteries in 12v configuration. the inverter has been turned off the whole time and now its saying 200 watts on classic display.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: not getting enough watts from solar panel

    A single 270 Watt panel isn't enough for 232 Amp hours @ 12 Volts. You knew that already.

    But you ought to be able to max out the panel easy enough by turning the inverter on and adding some loads. It doesn't take much to reach 200 Watts.
  • solarpowernovice
    solarpowernovice Solar Expert Posts: 134 ✭✭
    Re: not getting enough watts from solar panel

    yes i knew it wasn't enough panel to get them to 100% today (i hope this isn't harmful to the batteries) I just wanted to make sure I wasn't getting some kind of crazy voltage drop that i shouldnt be. I will turn a load on and see what happens... I am trying to mount my panels to the trailer but am having problems so for now i only have 1 panel hooked up becaus im too lazy to move the others. thanks.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: not getting enough watts from solar panel

    40 feet of 10 AWG at 30 Volts & 9 Amps ... about 1 Volt drop at most.

    BTW the silver colour is because it is pre-tinned. If you look really carefully at a cut end you can see the copper colour underneath. You may need a magnifying glass.
  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    Re: not getting enough watts from solar panel
    ... I am only seeing 190 watts on the midnite classic display. The solar panels specs are 39.2V Voc 9.44A Isc, it is in full sunlight laying flat and it is noon...

    Sounds about right! Panels have a Normal Operating Cell Temperature (NOCT) value, for this panel it's Right at 195 watts;
    Attachment not found.

    Here's a spec sheet.

    I would think your 270 watt panel is marginal for 235 Ah 12 volt battery bank, I lived for quite a while on 200 watt array and a 12v 215ah bank, but you have 470ah, 2 strings of 235 ah batteries.
    Cap.JPG 30.6K
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • solarpowernovice
    solarpowernovice Solar Expert Posts: 134 ✭✭
    Re: not getting enough watts from solar panel

    yes I have 2 more of the 270 watt solar panels, I just haven't permanently mounted them to my trailer yet. They are too big and heavy for me to carry around every time i want to charge my batteries, this will be solved as soon as i have them mounted then i can shorten my wire run too. Thanks for the clafication guys... I thought the solar panels were supposed to actually say close to 270 watts a piece on the charge controller.
  • solarpowernovice
    solarpowernovice Solar Expert Posts: 134 ✭✭
    Re: not getting enough watts from solar panel

    If thieves didn't breaking into my building on my land and steal all my stuff I wouldnt have to worry about making this system portable. My original plan when I bought all the components for my system was to put the solar panels on the buildings roof and all the components inside, but I cant be there all the time to guard my stuff :cry: too bad its illegal to set up boobie traps lol that would've been much easier and cheaper...
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: not getting enough watts from solar panel
    .....I thought the solar panels were supposed to actually say close to 270 watts a piece on the charge controller.
    Only in the sales literature, right next to the 46MPG sticker on your car.
    Powerfab top of pole PV mount | 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

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