I'm back and moving.. now the last minute questions..

ywhic
ywhic Solar Expert Posts: 621 ✭✭
Ok. I am moving to SW Texas next week. :cool:

I have 8 of the 145w (12v-18.05VMP/8.05IMP) panels.. and on testing was getting 9.2amp and 115-116w per panel output..

I have the Midnite 150 classic and plan on 4 strings of 2 panels each (aka 24v per se) into a 12v battery bank.. The Midnite Calc figures 80.6amps into a bank at full going..

I plan on using for starters just 2 of the Trojan T105RE for $130 (and $26 core) picked up in El Paso from Continental Battery when I get their..

I thought I would have cash to get a 720ah+ battery bank but funds are not there... as plumbing/water is kinda important. :p

So if I go with 220ah battery bank then a week later, goto 440ah battery bank how many panels should/can I turn on at the breaker box?? I have 2 panels on each breaker and 4 breakers total for the 1160w total..

I know I can't turn them all on or I will surely blow the batteries with too much power..

The Midnite calc says for 2 by 2 its 40.3 amps into the bank.. which would fit a C10 for 440ah bank.. and 20.1 amps for just 2 panels.. again C10 it appears..

Plan on just running a fan and small EER $29/year rated mini-fridge for now.. everything else is independent solar lights..

I did also give in an buy a small 1K genny for instant use to drill holes and run a small circular saw (I tested it and it works)..

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: I'm back and moving.. now the last minute questions..

    Yes, you really don't need like 74 Amps of current potential for 220 Amp hours of system.

    Look at it this way: the Imp is 8 Amps per panel. How many do you need to achieve around 22 Amps? Looks like three should suffice.
  • NorthGuy
    NorthGuy Solar Expert Posts: 1,913 ✭✭
    Re: I'm back and moving.. now the last minute questions..

    I'm just curious. Why are you going with 12V system, not 24V?
  • ywhic
    ywhic Solar Expert Posts: 621 ✭✭
    Re: I'm back and moving.. now the last minute questions..
    NorthGuy wrote: »
    I'm just curious. Why are you going with 12V system, not 24V?

    Stuff bought a year ago.. and went with 12v Xantrex 2000 for $320.. all I can afford right now.. Other 2K inverters for 24v were/are $600+..
  • ywhic
    ywhic Solar Expert Posts: 621 ✭✭
    Re: I'm back and moving.. now the last minute questions..
    Yes, you really don't need like 74 Amps of current potential for 220 Amp hours of system.

    Look at it this way: the Imp is 8 Amps per panel. How many do you need to achieve around 22 Amps? Looks like three should suffice.

    Do you think 4 panels (say 32 Amps) [2 sets of 2 switched on) would be ok for peak usage times when the sun is beaming.. so I can run some extra fans??
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: I'm back and moving.. now the last minute questions..

    If you are "stuck" at 12 volts now--You might see if you can purchase batteries in sets that can be re-wired to 24 volts down the road when funds/needs permit the change...

    I.e., pairs of 12 volt batteries, sets of 4x 6 volt batteries, etc... At least your battery bank will not be "locked into" 12 volts.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: I'm back and moving.. now the last minute questions..
    ywhic wrote: »
    I know I can't turn them all on or I will surely blow the batteries with too much power..

    Welcome back... The Classic can be told to limit its output to the battery. Lots of folks are "over-paneling" their systems so that they can get high output on a cloudy day. On a sunny day, the Classic can protect your batteries by limiting its output.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • ywhic
    ywhic Solar Expert Posts: 621 ✭✭
    Re: I'm back and moving.. now the last minute questions..
    BB. wrote: »
    If you are "stuck" at 12 volts now--You might see if you can purchase batteries in sets that can be re-wired to 24 volts down the road when funds/needs permit the change...

    I.e., pairs of 12 volt batteries, sets of 4x 6 volt batteries, etc... At least your battery bank will not be "locked into" 12 volts.

    -Bill

    The 1st week out will be 2 batteries @ 6v.. then a week later when I get a check I will be buying 2 more.. so I will have four 6v batteries at that point..

    Waiting on a call back from NAWS on the Crown GC 220 batteries.. their on sale for $120/each.. so I asked for quote on 4 shipped to me.. figured if they can ship to me I can save a trip 120 miles (on-way) to ELP, it may be worth saving the gas..

    The other option is 3 of WMart/Johnson Controls 115ah Marine batteries for starters.. that would a 345ah 12v battery bank for like $300..

    Opinions on that option would be good as well, though I prefer to do this once..
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: I'm back and moving.. now the last minute questions..
    ywhic wrote: »
    Do you think 4 panels (say 32 Amps) [2 sets of 2 switched on) would be ok for peak usage times when the sun is beaming.. so I can run some extra fans??

    I knew you were going to ask that. :D (Only because I remembered a discussion about compensating for A/C at one point.)

    As such, programming a current limit in the Classic as vtMaps suggested won't help; you need to manually connect/disconnect additional panels to meet the load requirements. Giant pain-in-the-anatomy.

    Best compromise would be connect five of the panels, limit the MidNite to 44 Amps, and hope the load demands don't exceed this when the batteries are fully charged (starts discharging again). That way the max rate to the batteries would be 20%, and probably would not happen as they are Somewhat self-limiting, and you would have up to about 500 Watts available "direct from panels" when all is working right. I seem to recall that an A/C unit draws around 500 Watts.

    Is this about what you want to do?

    With some more complex wiring the Classic's "waste not" feature could probably be utilized to do this more automatically.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: I'm back and moving.. now the last minute questions..

    If you are going to cycle the batteries deeply/often--Stay away from the Marine batteries unless you are getting them for near free.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • NorthGuy
    NorthGuy Solar Expert Posts: 1,913 ✭✭
    Re: I'm back and moving.. now the last minute questions..
    you need to manually connect/disconnect additional panels to meet the load requirements. Giant pain-in-the-anatomy.

    If it is only for a week, it isn't that hard to flip a breaker to increase the number of panels when there are more loads.
    ywhic wrote: »
    The 1st week out will be 2 batteries @ 6v.. then a week later when I get a check I will be buying 2 more.. so I will have four 6v batteries at that point.

    How about these famous $80 GC batteries that are available at Sam's Club?
  • ywhic
    ywhic Solar Expert Posts: 621 ✭✭
    Re: I'm back and moving.. now the last minute questions..
    As such, programming a current limit in the Classic as vtMaps suggested won't help; you need to manually connect/disconnect additional panels to meet the load requirements. Giant pain-in-the-anatomy.

    Is this about what you want to do?

    Switching 2, 4, 6, or all 8 on is a simple breaker throw for me..

    I will stick with 2 panels for 220ah and then do 4 panels for 440ah.. no A/C is planned as of this point. I wouldn't want to attempt with less than a 660ah bank and 6 panels..

    Thanks BB.. no not free.. Though the Sams Club has 220ah 6V GC2's for $101 out the door after taxes and core charge (since I don't have a core)..
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    Re: I'm back and moving.. now the last minute questions..

    Hi Al,

    Had been wondering just where you had gone. Welcome back here.

    Great advice so far. I do not have such a dim view of 12 V Marine Trolling batteries. They do appear to be real Deep-Cycle batteries. Have never torn one apart yet, however, and specs are quite lacking in general, other than AH Capacity, or Reserve Mins. Have used them before with very good results. Think that the GCs are real Deep Charge batts, no question, and are the real value deal.

    Glad that the A/C part of the conversation came up. In the past, I have said that my Samsung 6,000 BTU window A/C consumed about 500 Watts, which is generally true. But in the last heat-wave here, noted that it could consume as much as 650 watts in the afternoon, at peak heat. This may have somewhat to do with pressures that the compressor is working with or similar. It amazes me just how little that I know of all of the internal workings of an A/C, other evaporation and condensation at the hands of a compressor and fan/s.

    If I were looking for batts for a new system, in the range of what Al is, I would very, very seriously consider GCs. They are very inexpensive, tough - can take a real beating, and still smile about it all.

    Good Luck Al with the move. Have FUN setting up the new system and the new abode. 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.
  • ywhic
    ywhic Solar Expert Posts: 621 ✭✭
    Re: I'm back and moving.. now the last minute questions..

    The Sams GC2's are looking good.. $606 for 6 and 660ah.. I may go with 4 right off the bat.. then add the last 2 in say 2 weeks..

    The solar layout (as a refresher and for the new people).. (only shows 1 PV input set.. there will be 4 sets..)

    FinalSetupSmall.jpg

    ControlPanelSmall.jpg

    And the Classic 150 in testing with 2 panels in 99'F heat.. not in peak sun conditions.. (I got 9.2 amps per panel and 116w at one point..)

    Classic1025.jpg

    Heres my sun pattern for June 21st last year..

    PictureJune21st.JPG
  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    Re: I'm back and moving.. now the last minute questions..

    I'd setup your whole array and let MidNite CC limit, as others have said, that way if you ever have a cloudy day, you'll still have max charging.

    The Sam's club Here(Missouri) and Florida don't require a deep cycle battery for a core, I even had them except a big lawn mower battery! Check around, and keep your eyes open, ask your friends. I bet you can find 4 old car batteries!

    In a 24volt setup I have run an 5200btu A/C every summer except last year, on 4 golf cart batteries. I just purchased a Kenmore 5200btu EER of 11 air conditioner from Kmart(SearsLite) for @$155 w/tax, price was $159, 5% off at Kmart, and if you link through Fatwallet.com you can get another 5% cash back(in a couple months) buying on line. It's a Consumer reports 'Best Buy' in small A/C's and my previous one (EER of 10.7) is still running fine 6 years later. If you don't recall I only ran it when batteries were charged(I was in float) and for @3-5hours at night on energy saver.
    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.
  • ywhic
    ywhic Solar Expert Posts: 621 ✭✭
    Re: I'm back and moving.. now the last minute questions..

    After doing some numbers.. 440ah to start would be the best option.. then with 6 panels on would be 48 amps in (per Cariboo 8amp/panel).. and work to a C10.9..

    A little over 10% but thinking with loads running during peak hours I should be ok.. with 660ah I would loosely be at C9.7..

    My sister bought an ArticKing 6000 BTU that draw 4.9 amp and EER of over 11.. I checked with the Kilawatt and it sits at 4.6-4.9 amps..

    Thanks for all the input.. I will keep you all updated with pictures and such when 'we' get to the install..
  • Eric L
    Eric L Solar Expert Posts: 262 ✭✭
    Re: I'm back and moving.. now the last minute questions..

    One thing to think about with the AC unit is to use one of the two Aux ports on your Classic, so that the Classic signals a relay to disconnect the power to the AC when the battery voltage falls below a set-point. That way you won't hammer the batteries down just because it got cloudy or dark and you weren't there to shut off the AC. E.g., you run some Cat 5 signal wire (or similar) from the controller to an inexpensive relay like this one. You'll also need to make up a short extension cord for the air conditioner plug so you don't have to cut up the one on the unit. Set the Classic to "Vent Fan High" and you can pick a voltage to have the AC unit turn off automatically.
  • Surfpath
    Surfpath Solar Expert Posts: 463 ✭✭✭
    Re: I'm back and moving.. now the last minute questions..
    ywhic wrote: »
    Thanks for all the input.. I will keep you all updated with pictures and such when 'we' get to the install..
    Hi Al,
    Welcome back.. missed your bargain-seeking, system-maximizing posts. How's your cabin looking? Have you moved in or spent much time there yet. How is the heat treating you?
    Surfpath (back myself from a wee vacation)
    Outback Flexpower 1 (FM80, VFX3048E-230v, Mate, FlexNetDC) 2,730watts of "Grid-type" PV, 370 AmpHrs Trojan RE-B's, Honda 2000 watt genny, 100% off grid.