5.3KW Off-Grid working fine, but a question

deacon
deacon Solar Expert Posts: 33 ✭
in General Solar Power Topics #1
My upgrade to 5.3 KW Off grid was complete June 19th. Working splendid so far.
24 SUN 190 watt panels into 3 Xantrex MPPT 60-150 controllers and 10 80 watt Sharp panels into an Outback FM60. They all dump into a 1075 watt 24 volt Surette battery bank. Inverter is a Xantrex 4024 inverter.
On a clear day I have harvested 31.5 KW but average more like 25KW with partly cloudy.
I have been using all the power I generate running (2) 14,000 BTU portable heat pumps and (1) 8000 BTU portable A/C unit, plus the normal living items.
My question is this.
If I want to go on vacation, would it harm the panels to sit in the sun with no load?
My plan would be to turn off 3 of the 4 SCC's and just run one SCC to power the fridge, freezer, and a few other low watt pieces.
In full sun with no load attached does that hurt the solar panels?
Is there a preferred way to leave the system?
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Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: 5.3KW Off-Grid working fine, but a question

    It will not harm the panels to sit in the sun and do nothing. Leave the panels and charge controllers connected to the batteries; all will be fine. Shut off the loads, and turn off the inverter if you like. No problem.
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  • stephendv
    stephendv Solar Expert Posts: 1,571 ✭✭
    #3
    Re: 5.3KW Off-Grid working fine, but a question

    I'm not sure how the Xantrex MPPT control the absorb cycle, but my morningstar will always enter absorb in the morning, even if the battery is at 98% State of charge.
    So if you have absolutely no loads, I would check that you're not needlessly putting the batteries through a 2+ hours absorb cycle every day. If the CC forces an absorb, then you could shorten the time to 30 mins or 1 hour to reduce overcharging.
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  • petertearai
    petertearai Solar Expert Posts: 471 ✭✭✭✭
    #4
    Re: 5.3KW Off-Grid working fine, but a question

    The fm80 has 2 settings for absorb. Time and end amps.If you have the end amps set corectly then the absorb will stop before the absorb time if the end amps value is reached.
    The trick is sorting out your end amp setting.
    My situation is a holiday home used every 2 to 3 weeks.While away the absorb times on the log are very short as the end amps is quickly reached. But while in residence the time will go out toward the time setting.
    2225 wattts pv . Outback 2kw  fxr pure sine inverter . fm80 charge controller . Mate 3. victron battery monitor . 24 volts  in 2 volt Shoto lead carbon extreme batterys. off grid  holiday home 
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  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #5
    Re: 5.3KW Off-Grid working fine, but a question

    deacon, as Cariboo said, leave your charge controllers on.

    If you haven't seen the discussions on mini-split heat pumps, you should do a quick search here. Doesn't get much better than 26 SEER, I doubt your portable units are rated anywhere near that high.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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  • deacon
    deacon Solar Expert Posts: 33 ✭
    #6
    Re: 5.3KW Off-Grid working fine, but a question

    Thanks for help Guys.
    I plan on leaving my refer, freezer and a few small loads on.

    Just curious. When a solar panel sits in the sun without being connected to anything at all, is there any damage possible?
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #7
    Re: 5.3KW Off-Grid working fine, but a question
    deacon wrote: »
    ..

    Just curious. When a solar panel sits in the sun without being connected to anything at all, is there any damage possible?

    Sure, a seagull could come by, and drop a clam on it, and break the panel trying to open a clam.

    But sitting in the sun, won't hurt a PV panel.
    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

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #8
    Re: 5.3KW Off-Grid working fine, but a question

    now if you meant literally sitting in the sun then yup, it'll be damaged as it would most likely melt and vaporize before you can say aw crap.:cry::p:p:p
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  • deacon
    deacon Solar Expert Posts: 33 ✭
    #9
    Re: 5.3KW Off-Grid working fine, but a question

    Funny.
    The reason I asked that I read on the "internet forum" that leaving a new solar panel in the sun not connected to anything could damage it.
    A case of Internet Knowledge once again.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #10
    Re: 5.3KW Off-Grid working fine, but a question
    deacon wrote: »
    Funny.
    The reason I asked that I read on the "internet forum" that leaving a new solar panel in the sun not connected to anything could damage it.
    A case of Internet Knowledge once again.

    A, the Misinformation Super Highway! :p
    I'd love to hear the genii explain how that could be. :roll:
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