Bringing my new system online

MichaelKMichaelK Registered Users Posts: 25 ✭✭
I'm in the final stages of bringing our second generation solar system online.  It consists of 15-300watt Renogy panels, Midnight Classic200, eight-Trojan L16-REb batteries at 48 volts (370ah), and a Schneider XM+6848 inverter.  The ultimate goal is supply power to our vacation/retirement cabin and power our 1.5hp 240VAC well pump.

I've wired the panels in a 3S5P configuration, with each 3 panel array producing ~700-750 watts in the real-world.  I think this system is over panelled and plan on reducing the overall wattage by facing some of the arrays either SE or SW so the amperage at noon doesn't exceed the capacity of the controller.

Right now though, electrical demand is limited to weekends only, with zero loads during the week.  The cabin does not yet have an AC refrigerator, so when we're not there, everything is shut off.  I'm concerned about all those kw heating my controller when it's essentially just sitting there.

Assuming my battery bank is fully charged when I go home Sunday afternoon, how many watts would be needed to keep a fully charged bank floating.  My idea is to keep just one array on-line during the week to keep floating the batteries, then switch on three on weekends when we visit.  I don't plan on switching on all 5 arrays until I install the refrigerator, and start trying to pump water.

Opinions?

Comments

  • Dave AngeliniDave Angelini Solar Expert Posts: 3,258 ✭✭✭✭
    I think you are over thinking this :) The CC will go to float very quickly if programmed correctly on a bank that is not cycling.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail offgridsolar@sti.net

  • EstragonEstragon Registered Users Posts: 1,430 ✭✭✭✭
    Also, the classic has a "skip days" setting you can use to prevent it from going through a bulk/absorb cycle every day. It will still float every day, and only bulk after 'X' such float only days, or if voltage drops below your "rebulk" setting.

    I wouldn't bother switching off parts of the array during the week. If the power isn't being used, the pv simply won't create it in the first place. I do shut off all the inverters though, and open main AC breakers.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • Raj174Raj174 Solar Expert Posts: 417 ✭✭✭✭
    MichaelK,
    You can limit the charging amps with a setting in the controller to 48 to 50 amps, that's about a 13 percent rate, and still have a south facing array. And as Dave indicated, the controller, in float, does not heat due to high wattage because the MPPT function will move the power point to a point of low wattage production to supply the needed power to float the battery. 
    Sounds like a good system, good luck with it.

    Rick 
    12 x 300W Renogy PV, MNE175DR-TR epanel modified, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 195AH HI Power LiFePO4 no BMS, 4000W gen.
  • MichaelKMichaelK Registered Users Posts: 25 ✭✭
    How hot is a classic that's charged up to the floating stage supposed to get?  At 1pm, the batteries are well past fully charged, and floating, but the controller is still very hot to the touch.  That's what I'm concerned about?  I'm now in the learning stages of working with MPPT, now that I've ditched my old 12V PWM system.  Electronics running hot makes me nervous!  I haven't switched the controller to a sealed marine mode, so I'm not expecting it to get so hot.
  • Raj174Raj174 Solar Expert Posts: 417 ✭✭✭✭
    Has the fan been running? My Classic 150 doesn't get too hot to touch, just very warm. Maybe 110˚.
    12 x 300W Renogy PV, MNE175DR-TR epanel modified, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 195AH HI Power LiFePO4 no BMS, 4000W gen.
  • MichaelKMichaelK Registered Users Posts: 25 ✭✭
    I believe so, but I'll have to focus my attention on that next weekend when I go up.

  • Raj174Raj174 Solar Expert Posts: 417 ✭✭✭✭
    Just in case you don't know, Midnite has local app software that uses a network connection to the Classic to monitor power production, PV and battery charging, also Classic temperature. Settings can also be adjusted with the app.
    12 x 300W Renogy PV, MNE175DR-TR epanel modified, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 195AH HI Power LiFePO4 no BMS, 4000W gen.
  • EstragonEstragon Registered Users Posts: 1,430 ✭✭✭✭
    In float, mine (150) currently at 40°c on the PCB and 34°c on the FET. Ambient is ~19°c. The 200 might run a bit warmer, but I don't know for sure. If yours is running more than a couple of degrees higher, you might want to check with MN.

    There's also a third party app for monitoring (only - no changing settings) classics that works better on tablets and phones than MN LocalApp.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • VicVic Solar Expert Posts: 2,811 ✭✭✭✭
    edited September 2 #10

    Speaking of heating of Classics,   of course  the PV input voltage into the Classic  and the output current that the Classic is delivering both have a reasonably large effect on the heating.

    For a given battery voltage,   higher Vin  and output current  have  a direct effect,   as does ambient temperature around the Classic,  or any other MPPT Charge Controller.

    Presently,  one Classic 150 in Float,  is outputting 53 A,   Vin is 98 V,   FETs are 51.8 C,  PCB is 50 C,  and the ambient temp is about 65 F,   and the internal fans run about 60% of the time.

    This system  runs a relatively high Vin for a Cl 150  --  106 V STC String voltage,   which causes the CC to run a bit harder than it would with a bit lower Vin.

    The LocalApp is a good tip raj Rick.   There is also MyMidnite,   a MidNite Web site where you can setup  a free Account,   which allows remote monitoring (but no control)  of your Classic/s,  workdwide,   with 5 - 10 minute resolution of recorded data.

    FWIW,   Vic


    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • EstragonEstragon Registered Users Posts: 1,430 ✭✭✭✭
    Current and voltage certainly makes a difference. My temps were just for floating - no other loads to speak of at the time. Vin ~65v into 12v bank. Float only temps with Vin ~100v into 48v bank about the same.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • mike95490mike95490 Solar Expert Posts: 7,249 ✭✭✭✭
    My 200 with a 2Kw array, has it's fans running much of the time.  About 190Voc
    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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