ADDING PANELS

zozomike
zozomike Solar Expert Posts: 134 ✭✭✭
in Off Grid Solar & Battery Systems #1
Our 2nd array is 6 each, S/W 265 panels with a FM 60 CC, What problems am I going to create if I add 4 more S/W 265, and change the CC to the FM80 ?

Off grid, all solar, passive and active (winter wood heat supplements) PV DHW.

Array 1-- 12 Sunpower 250, Outback FM 100 3kw

Array 2-- 12 Sunpower 250, Outback FM 100 3kw

Well array 780w, 6 Kyocera 130 w with Grundfos sqflex 11 and cu200 to elevated storage, ( 2- 330 g tanks,) no battery storage at well

10 24 volt Battle Born Lithiums

Outback Flexpower Two, VFXR 3524A 7kw


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  • Desert Rat
    Desert Rat Solar Expert Posts: 147 ✭✭✭
    #2
    Ten 265 watt panels makes an array of 2650 watts, which is too much for a single FM80 on a 24 volt battery bank. You could add an FM80 and retain the FM60 and split the ten panels into two arrays, one array of six panels and another array of four, each on their own CC.
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  • softdown
    softdown Solar Expert Posts: 3,896 ✭✭✭✭
    #3
    The more I learn, the less I seem to know. You are going to have a lot of solar. So many advantages in the efficiencies of 48 volts. Usually makes sense when a user breaks the ~2000 watt barrier. Have you considered going 48 volts?

    We have a user that really wants to switch to 48 volts with his ~4000 watt set up...as I recall. But his $5000 24 volt forklift battery keeps him locked into 24 volts. Edit: I believe his name is Photowit....who recently posted. So lots of 24 volt experience.

    Just a thought....

    I am currently rejuvenating a 24 volt forklift battery, it takes a long time. For that reason, my next bank may be 24 volts. I'm going to put up some easterly and westerly panels. Maybe some roof panels too. Great time to panel up.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • zozomike
    zozomike Solar Expert Posts: 134 ✭✭✭
    #4
    Thanks for the replys,
    Yes I have thought of a 3rd controller, but my panels are 75' from the CC and balance of system. which would mean a 75' trench trying to avoid the 2 lines I have already run, my backhoe is down for new hydraulics and my back is 67 Y/O.
    We are building an off grid totally solar place here and it seems to go on forever... I thought the system as described would be adequate, ( was when I was alone, but romance got in the way of power frugality) Problem is, though we are in a very sunny state, we are at a spot that receives persistent afternoon cloud cover. We can be getting 4 kw at 11 am, and half that through the rest of the solar day. This issue is from Aug-.Sept through Mar.
    Yes I got locked in to the 24 volt system due to ignorance, going 48 would mean a new battery, a new inverter.
    My thought was if the FM 80 ( up to 2500 watts at 24 VDC) actually saw more incoming it would just clip that to it's comfort zone??

    Off grid, all solar, passive and active (winter wood heat supplements) PV DHW.

    Array 1-- 12 Sunpower 250, Outback FM 100 3kw

    Array 2-- 12 Sunpower 250, Outback FM 100 3kw

    Well array 780w, 6 Kyocera 130 w with Grundfos sqflex 11 and cu200 to elevated storage, ( 2- 330 g tanks,) no battery storage at well

    10 24 volt Battle Born Lithiums

    Outback Flexpower Two, VFXR 3524A 7kw


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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #5
    zozomike wrote: »
    My thought was if the FM 80 ( up to 2500 watts at 24 VDC) actually saw more incoming it would just clip that to it's comfort zone??

    That is true of most MPPT CCs, but check the manufacturer's data for the maximum recommended input power. Some put no limits. Others limit at values like 150% or 200%.
    With a PWM CC none that I know of will accept more than about a 10% panel overage.

    SMA SB 3000, old BP panels.
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  • softdown
    softdown Solar Expert Posts: 3,896 ✭✭✭✭
    #6
    What part of NM? I'm getting my big trencher up....I hope. Ordered new fuel pump. I'm not far from Taos.

    Edit: Actually an 8' trencher. I think it goes 6' deep.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #7
    zozomike wrote: »
    but my panels are 75' from the CC and balance of system.
    I think I have the same battery, and have been reading the forum, that the battery is misrepresented as a 804 ah battery and should be more like 660Ah, so you are approaching or surpassing the max array needed. Many have suggested using arrays at different angles to maximize the balance of charging capabilities. You might be able to place the third array closer to the home facing perhaps more westernly to catch evening sun, since it would appear you have less charging in the evening. This might give you a boost going into the evening hours.
    zozomike wrote: »
    My thought was if the FM 80 ( up to 2500 watts at 24 VDC) actually saw more incoming it would just clip that to it's comfort zone??
    I believe the FM80 has no problem limiting over current and can be set for maximum through current. 2500 watts should be no problem are rarely limiting the maximum charging of 2500 watts. which should be just less than 80 amps on a typical day.

    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.
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  • softdown
    softdown Solar Expert Posts: 3,896 ✭✭✭✭
    #8
    According to this line of reasoning, I could use my existing FM80 for the east and west panels that I am planning on. There is an accepted name for doing this but I forget the term.

    Many believe in it, others vehemently deny its viability. Sort of like battery de-sulfation....lots of disciples and lots of non-believers. When I talked to a forklift battery rejuvenation service, I got the opinion that battery de-sulfation was probably the key part of the process.
    Photowhit wrote: »
    I think I have the same battery, and have been reading the forum, that the battery is misrepresented as a 804 ah battery and should be more like 660Ah, so you are approaching or surpassing the max array needed. Many have suggested using arrays at different angles to maximize the balance of charging capabilities. You might be able to place the third array closer to the home facing perhaps more westernly to catch evening sun, since it would appear you have less charging in the evening. This might give you a boost going into the evening hours.

    I believe the FM80 has no problem limiting over current and can be set for maximum through current. 2500 watts should be no problem are rarely limiting the maximum charging of 2500 watts. which should be just less than 80 amps on a typical day.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Desert Rat
    Desert Rat Solar Expert Posts: 147 ✭✭✭
    #9
    Unless I'm missing something, 10 panels is going to be problematic. You can't have more than 3 panels per string in order to stay under the maximum Voc of 150V for the FM80. Seems it would be best to go with 9 panels, 3 strings of 3 each.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #10
    Desert Rat wrote: »
    Unless I'm missing something, 10 panels is going to be problematic. You can't have more than 3 panels per string in order to stay under the maximum Voc of 150V for the FM80. Seems it would be best to go with 9 panels, 3 strings of 3 each.

    How about 5 strings with 2 panels per string? (It's a 24 volt system).

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • Desert Rat
    Desert Rat Solar Expert Posts: 147 ✭✭✭
    #11
    vtmaps wrote: »

    How about 5 strings with 2 panels per string? (It's a 24 volt system).

    --vtMaps

    Right you are. I told you I was missing something! I was thinking 48V.
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  • zozomike
    zozomike Solar Expert Posts: 134 ✭✭✭
    #12
    Yes I was thinking 5 strings, thanks vtmaps. softdown we are in the southern mountains, a long drive on a trencher.

    Off grid, all solar, passive and active (winter wood heat supplements) PV DHW.

    Array 1-- 12 Sunpower 250, Outback FM 100 3kw

    Array 2-- 12 Sunpower 250, Outback FM 100 3kw

    Well array 780w, 6 Kyocera 130 w with Grundfos sqflex 11 and cu200 to elevated storage, ( 2- 330 g tanks,) no battery storage at well

    10 24 volt Battle Born Lithiums

    Outback Flexpower Two, VFXR 3524A 7kw


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