What equipment needed for solar panels on FX 24v inverter

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  • BB.BB. Super Moderators, Administrators Posts: 29,488 admin
    Re: What equipment needed for solar panels on FX 24v inverter

    Yep... And a couple of points:
    1. Check polarity of panel/controller connections. Should not cause damage--but you always want to be sure).
    2. You don't really need a circuit breaker for a single connection... However, when you put three or more strings of panels in parallel, each panel string should have its own series protection breaker/fuse (roughly 2x Isc if not listed elsewhere). This limits the current if one panel gets an internal short so the other panels cannot over heat the shorted panel/wiring.
    The panel voltage should be pretty stable at Voc with weak sunlight and a voltmeter as load (Voc peaks with minimal sunlight, and as the panels heat up, you may see a 10%-20%+ drop in Voc/Vmp voltage--that is normal). The panel output current is directly proportional to the amount of sunlight hitting the panel.

    The 55 volts vs 65 volts is a pretty wide range of Vmp/Voc voltage... It will not hurt anything to connect them all in parallel--but it may not give you optimum power output from the charge controller.

    When you get everything connected (all 16 panels--say 4 panels per string)... See what your total power output is in full sun with a discharged/loaded battery (so controller is in MPPT mode--maximum output current--Charged batteries will not accept full current).

    If you are over ~60%% of your panels ratings (full noontime sun, clear day, etc.)--then you are probably doing the best you can... If you have less than 50% of panel rating, you might have to look at the array to find bad panels and/or try another configuration (try 4 strings of Brand A, measure power; then try 4 strings of Brand P, measure power--see how much total power from two tests vs everything connected together).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • castillojcastilloj Solar Expert Posts: 208
    Re: What equipment needed for solar panels on FX 24v inverter

    Im currently using my generator charging my batteries. should i just stop charging so that i can hook up the charge controller first?
    Also do i just combine the astros and photowatt wires together so that they go to the MPPT?
  • BB.BB. Super Moderators, Administrators Posts: 29,488 admin
    Re: What equipment needed for solar panels on FX 24v inverter

    Each series string of 4 panels (assuming that is your configuration) should then be connected + to + and - to negative (parallel, current will add, voltage will remain the same).

    And, eventually, you should get some fuses or circuit breakers (your choice) to protect each series string (before you make the + parallel connection). Maybe around a 15 amp fuse/breaker for each series string.

    This will reduce the chance of fire if a solar panel or solar panel wiring gets shorted.

    You do not want the generator running while doing your Solar Charge Controller testing... You may see very little charging current from the solar charge controller because the AC battery charger is also supplying current to the battery bank (depending on battery voltage and each charge controller's voltage set-points).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • castillojcastilloj Solar Expert Posts: 208
    Re: What equipment needed for solar panels on FX 24v inverter

    Since i have a series of 4 astros and 4 photowatts. could i just combine them? i dont have a combiner but i can just wire nut them together.
  • BB.BB. Super Moderators, Administrators Posts: 29,488 admin
    Re: What equipment needed for solar panels on FX 24v inverter

    Yes, that would work and be "safe"... Two or one arrays do not need series protection fuses.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • castillojcastilloj Solar Expert Posts: 208
    Re: What equipment needed for solar panels on FX 24v inverter

    Hey BB, i have another question for you. i have 8 rolls 600 batteries, a outback fx2424 inverter using a SDMO Diesel 12kw generator. what should my settings be for charging batteries/float/EQ? Right now im just using default settings on My Outback Mate.
    Also on the MPPT charger, should i just be seeing the LED's Correspond on what charge the batteries are? I didnt purchase the MPPT 60 that has the led screen.
  • BB.BB. Super Moderators, Administrators Posts: 29,488 admin
    Re: What equipment needed for solar panels on FX 24v inverter

    Castilloj,

    I am not the Outback (or any) programming expert here--so others may be able to help you better...

    This Google Search "charge site:www.surrette.com" will give you the Rolls/Surrette recommended charging information.

    Another good read is the Trojan User Guide (PDF Download). They have their recommendations in there...

    If you are using the battery banks a lot--the Absorb Timer should probably set for a longer time and your system. And in the winter, you may never get into Float.

    Also watch your battery water usage... If you use a lot--too much charging and crank down on the voltages/time. If you are using hardly any water--You may need to crank up the voltage and check if you are drawing too much power for the charging current you have available.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • castillojcastilloj Solar Expert Posts: 208
    Re: What equipment needed for solar panels on FX 24v inverter

    Hey Bill, do these readings look ok from my MPPT60?
    Array voltage-45.91 V
    Imput power-238.95 A
    Battery Current-8.76 A
    Output Power-239.61 W
    Array Current-5.22 A
    Battery Temperature-37 C
    LED State-Green
    Target REgulation Voltage-30.07 V
    Battery Voltage 27.36 V
    Array VMP-(last sweep) 45.93 V
    Array Voc(last Sweep)-58.73 V
    Array Pmax(last sweep)-242.69 W
    Ah Charge Resetable-557.20 Ah
    Heatsink temperature-40 C
    Ah charge total -557.20 Ah
    RTs Temperature-37 C
  • BB.BB. Super Moderators, Administrators Posts: 29,488 admin
    Re: What equipment needed for solar panels on FX 24v inverter
    castilloj wrote: »
    Hey Bill, do these readings look ok from my MPPT60?

    My impressions (again, I do not know Outback product except for what I read here):

    Array voltage-45.91 V
    --A bit too low... I would expect it to be more in the 55+ volt range in good sun and properly operating MPPT.

    Input power-238.95 A
    Battery Current-8.76 A
    Output Power-239.61 W
    Array Current-5.22 A
    --Your arrays should each be around 6-7 amps maximum Imp in full sun/ideal conditions... You are getting less than 1/2 of that... I would try each array by itself and see what the Vpanel/Ipanel numbers are for each. You may have a dead panel or string.

    Battery Temperature-37 C
    --Very warm for a lead acid battery bank... Do you have a Remote Battery Temperature Sensor hooked up and configured? Or is this the Room/Charge controller temperature? (98.6F)? If the batteries are this warm--you should look at ventilation and other heat sources (sun through wall/window), etc.

    LED State-Green
    Target Regulation Voltage-30.07 V
    --I do not know the Outback Terms... 30 Volts is a bit high for normal Bulk/Absorb charging. I would tend towards 29.0 volts or so. For Equalization of a battery bank, that is fine. (Note below, you are not hitting that voltage yet, see below, so nothing "bad" is happening yet). Just watch your electrolyte levels (both water levels, and specific gravity to tell you what your battery thinks of your loads/charging).

    Battery Voltage 27.36 V
    --Ideally, you should hit your "Target" voltage at least a once or twice a week (and stay there for a couple hours) to insure the battery is getting >90% state of charge.
    Array VMP-(last sweep) 45.93 V
    Array Voc(last Sweep)-58.73 V
    --That Voc sounds a bit low... You should be hitting ~65-84 volts (depending on temperature and other loading issues)... I don't know "Outback", so I cannot tell you if this Voc is normal or not. In earlier posts you seem to have reported low Voc (Voltage open circuit)--Not usually a good sign for panel health. You may have one or two panels that are not performing well... If you can, with the system operating, measure the voltage across each panel--Ideally, each panel should match all the others within a volt or so. More than that, you have a bad panel/poor connection somewhere.

    Array Pmax(last sweep)-242.69 W
    --On a good sunny day, with battery bank "needed recharging" and/or heavy loads, I would expect a perfectly running system to be giving you at least 500 watts (great day, 700 watts or better)... (assuming you have 880 watts of solar panels, and the charge controller is in MPPT mode and trying to push as much current as possible in the battery bank--And the panels are pointing at the sun, no shade, no visible clouds/haze, clean panels, etc.). (Obviously, not being there and not having any way to know the amount of sun you are getting at any one time--This is all major guess work on my part).

    Ah Charge Resetable-557.20 Ah
    Heatsink temperature-40 C
    --That sounds like the 37C "battery temperature" is really the Charge Controller temperature

    Ah charge total -557.20 Ah
    RTs Temperature-37 C[/QUOTE]

    My two cents worth--I hope it was helpful.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • castillojcastilloj Solar Expert Posts: 208
    Re: What equipment needed for solar panels on FX 24v inverter

    i got those readings by just using 4 photowatts and 4 astros connected in series.
    i just tested a photowatt by itself and i got 38 v.
  • BB.BB. Super Moderators, Administrators Posts: 29,488 admin
    Re: What equipment needed for solar panels on FX 24v inverter

    One Photowatt panel or one string of 4 panels in series?

    Also, when you disconnect one string at a time, what does your array current become between the options (panel strings A, B, A+B in parallel).

    In a way--look at this panels as sort of "D Cell" flashlight batteries in series/parallel. The panels are reasonably closely matched--so you are looking for large differences (high/low voltage in the panels somewhere, one string that is not providing enough/any current, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • castillojcastilloj Solar Expert Posts: 208
    Re: What equipment needed for solar panels on FX 24v inverter

    4 panel in series.
  • BB.BB. Super Moderators, Administrators Posts: 29,488 admin
    Re: What equipment needed for solar panels on FX 24v inverter

    If this is the correct Photowatt panel(s) (PDF), then you should be seeing somewhere around 65-80+ volts with 4 panels in series, full sun, using a digital volt meter (no loads on panels). Each panel should read nearly 21.7 volts Voc (Voltage open circuit) with a DMM.

    If you are doing this measurement with the charge controller connected (MPPT?) then, you should be seeing something like 4x17.3volts=69.2 volts (or as low as 55 volts in hot weather).

    Assuming everything is working and I understand your setup...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • castillojcastilloj Solar Expert Posts: 208
    Re: What equipment needed for solar panels on FX 24v inverter

    Okay i just moved my panels so i get a better way to hook them up. and i connected 4 in series
    + - + - +- +- and im getting 137 volts and when i would remove one panel it dropped to 97 volts.

    And i got these readings with full noon sun , and no load.
  • castillojcastilloj Solar Expert Posts: 208
    Re: What equipment needed for solar panels on FX 24v inverter

    This is what im getting right now. i connected 6 Astro 3x3 in series and i connected 6 Phtowatts 3x3 in series.

    ARRAY
    Array Voltage-43.59 V
    Array Current-19 A
    Sweep VMP-43.56 V
    Sweep-VOC-61.10 V
    Sweep Pmax-521 W

    BATTERY
    Battery Voltage-27.47 V
    Target Voltage-31.10 V
    Charge Current-25.7 A
    Charge State-MPPT
    Output Power-806 W

    Resetable Counters
    Amp Hours-1607.5 Ah
    Kilowatt Hours-41 kWh
  • BB.BB. Super Moderators, Administrators Posts: 29,488 admin
    Re: What equipment needed for solar panels on FX 24v inverter

    The "Target Voltage" of 31 volts is high for normal charging (assuming that is the Bulk/Absorb charge voltage setting)--Should be closer to 28 volts unless you are trying to equalize a flooded cell battery bank.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • castillojcastilloj Solar Expert Posts: 208
    Re: What equipment needed for solar panels on FX 24v inverter

    Yeah i did press the equalize button on the MPPT. BUt what do you think of everything else?
  • BB.BB. Super Moderators, Administrators Posts: 29,488 admin
    Re: What equipment needed for solar panels on FX 24v inverter
    castilloj wrote: »
    This is what im getting right now. i connected 6 Astro 3x3 in series and i connected 6 Phtowatts 3x3 in series.

    I am confused here--Do you have 3 panels in series, and two panel strings in parallel (3x2=6 panels) for each type... Then place those strings in parallel to the charge controller (2x Astro and 2x Photowatts in parallel for four parallel strings total)?

    Also, I had asked you in an earlier post if I had the correct data sheets for the Astro and Photo watts--there may have been several models that where kind of close and I was not sure which ones you had.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • castillojcastilloj Solar Expert Posts: 208
    Re: What equipment needed for solar panels on FX 24v inverter

    I have 2 3xpanels in series for Astros and for Photowatts. and the sheets were correct for the panels i have.
  • BB.BB. Super Moderators, Administrators Posts: 29,488 admin
    Re: What equipment needed for solar panels on FX 24v inverter

    So you have three panels in series, two strings in parallel for a total of 6 panels for the Astro; and the same thing for the Photowatt (3 in series, two parallel strings for a total of 6 Photowatt). Then those strings in parallel for a total of 4 parallel strings with 12 panels attached to your MorningStar TS 60 amp MPPT controller?

    Sorry to keep asking the question--I just want to understand your exact setup before I make uninformed guesses (:roll:;)) about your system.

    -Bill :D
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • castillojcastilloj Solar Expert Posts: 208
    Re: What equipment needed for solar panels on FX 24v inverter

    Yes thats correct. and i really appreciate your help on this. Im a total newby with this stuff.
  • BB.BB. Super Moderators, Administrators Posts: 29,488 admin
    Re: What equipment needed for solar panels on FX 24v inverter

    From the data sheets:
    Astro Power:
    Pmp = 120 watts
    Voc = 21 volts
    Vmp = 16.9 volts
    Isc = 7.7 amps
    Imp = 7.1 amps
    Fuse = 15 amps

    Photowatt
    Pmp = 100 watts (105/110?)
    Voc = 43.2/21.6 volts
    Vmp = 34.4/17.2 volts ("24/12 volt jumper?)
    Imp = 2.9/5.8 amps
    Assuming the PhotoWatts are configured for "12 volts"--your array would look like:

    Vmp = 50.7 to 51.6 volts (3xVmp for each vendor)
    Imp = 25.8 amps
    Pmp = 1,260 Watts

    Now, the above assumes a perfect day, high noon, and very cold weather... In reality, depending on panel temperatures, the Vmp can be down to ~80% of STC (standard test conditions). That also derates the 660 watts too...
    Array Voltage-43.59 V
    Array Current-19 A
    Sweep VMP-43.56 V
    Sweep-VOC-61.10 V
    Sweep Pmax-521 W
    • 43.56 volts / ~51 volts STC = 0.85 Vmp depression (not bad for "hot panels)
    • 19 amps / 25.8 amps = 0.73 current ratio (not great, is controller in MPPT mode and batteries somewhat discharged?)
    • 521 watts / 1,260 watts = 0.41 (not very good--Does not match Imp*Vmp=828 watts)
    • 828 watts / 1,260 watts = 0.66 (low--but may be OK for conditions/old panels).
    The controller output numbers:
    BATTERY
    Battery Voltage-27.47 V
    Target Voltage-31.10 V
    Charge Current-25.7 A
    Charge State-MPPT
    Output Power-806 W
    Hmmm:
    • 25.7 amps * 27.47 volts = 709 watts [fixed equation]
    Output seems to match input (within accuracy of MPPT controller (within 10% is probably the best accuracy you can expect from a typical Solar Charge controller's current/voltage/power readings.

    MPPT mode says the controller is trying to take as much power as it can take from the solar panels (not limited by battery being nearly fully charged).

    I would try disconnecting one string of panels at a time, and see if one of the strings is not supplying 1/4 of the load...

    I think your controller is working fine (my guess)... You may have a panel (or string) that is under performing (age/damage). Check each string for current flow. If you can, check the voltage drop across each panel and see if you find one way low than the rest.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • castillojcastilloj Solar Expert Posts: 208
    Re: What equipment needed for solar panels on FX 24v inverter

    BB , do you think me using 12 awg wire from the panels to the charge controller may also be the problem? especially since the panels are about 75 ft from the charge controller?
    Also does anyone know if its possible to access the mppt 60 via the web?
    ived tried http//tsmppt+serialnumber and i get nothing.
    Thanks
  • KeithWHareKeithWHare Solar Expert Posts: 140 ✭✭✭
    Re: What equipment needed for solar panels on FX 24v inverter
    castilloj wrote: »
    BB , do you think me using 12 awg wire from the panels to the charge controller may also be the problem? especially since the panels are about 75 ft from the charge controller?

    You may want to take a look at the "Any Voltage Voltage Drop Calculator" at http://www.electrician2.com/calculators/vd_calculator.html

    For 50 volts, 25 Amps across 75 feet of #12 copper wire, you can expect about a 15% voltage drop. That is, if you start with 50 volts, you are going to end with about 42 volts.

    For 50 volts, 25 amps, #12 wire, about 10 feet gives you a 2% voltage drop.

    For 75 feet, to get that to a 2% voltage drop, you would need to use #3 copper wire.

    With 75 feet of #12, you are losing a lot in the wire.

    Keith Hare
  • BB.BB. Super Moderators, Administrators Posts: 29,488 admin
    Re: What equipment needed for solar panels on FX 24v inverter

    Och... As Keith said, 75' at 25.8 amps will give you around 7.4 volt drop on 12 AWG wire:
    • 7.4 volts * 25.8 amps = 191 watt losses from wiring run
    Those voltage drops may account for most of the low Vmp you are seeing at the charge controller.

    You have three choices now...
    1. Leave as is... You are loosing power--but everything is working.
    2. Go with 3 AWG or heavier wire for 2% or less voltage/power losses
    3. Look at wiring the arrays into a ~100 VDC Vmp array (put 6 panels in series, then parallel the Photowatt/Astropower panels together):
    Vmp~100 VDC, Imp = 12.9 amps. 75' run:
    • 10 AWG wire, 12.9 amps, 75' run, => 2.3 volt drop or ~2.3% losses
    • 12 AWG wire, 12.9 amps, 75' run, => 3.7 volt drop or ~3.7% losses
    10 AWG would be great--Keeping your 12 AWG wire is not the worst solution out there to get you up and running and saving the cost of a run of 10 AWG wire.

    #3 should work OK--Voc-cold at 14 degrees Fahrenheit will be around 145 volts... Not great, but probably better than you have right now. But--You are in Haiti--So what is your minimum temperature? 70F? ;) That drops Voc-cold to 128 volts--perfect for your system.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • castillojcastilloj Solar Expert Posts: 208
    Re: What equipment needed for solar panels on FX 24v inverter

    Hey BB, sorry to bring this back up, but ived messed around with my panels to the point that im only gonna use the photowatts instead of the astros. i noticed that the majority of the astros were badly rusted where the connections are made. So i connected 8 photowatts. 4 in series and 4 in series, and it gives me 156 v total.
    im not sure i connected the right.

    the first positive of the first series i connected with the first positive of the second series
    and then i ran it to breaker

    I then ran the Negative from the 4th panel in first series and connected with the 4 th panel on the second series and connected to breaker.

    when i would check voltage on the photowatts by themselves i would get 38v.
    so i was getting 152v on each set of 4 panels. and when i combined them it made them 156v.
  • BB.BB. Super Moderators, Administrators Posts: 29,488 admin
    Re: What equipment needed for solar panels on FX 24v inverter

    You cannot use the 4x photowatts in series... That gives you >152 volts (apparently) and will damage/void the warranty on most Solar Charge controllers (most have 150 VDC or less maximum input voltage).

    If, I am understanding you correctly.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • castillojcastilloj Solar Expert Posts: 208
    Re: What equipment needed for solar panels on FX 24v inverter

    so could i hook them 3x3x3= into the mppt60?
  • BB.BB. Super Moderators, Administrators Posts: 29,488 admin
    Re: What equipment needed for solar panels on FX 24v inverter

    The Photo Watts appear that they can be wired, internally in series or parallel output:
    Photowatt
    Pmp = 100 watts (105/110?)
    Voc = 43.2/21.6 volts
    Vmp = 34.4/17.2 volts ("24/12 volt jumper?)
    Imp = 2.9/5.8 amps

    So, you have several options on how to wire up your array (make best use of the total number of Photowatt's you wish to use).

    And I am not quite sure what 3x3x3 wiring is? 3x3 series/parallel for 9 panels total?

    How cold does it get where you are at? ~100 VDC Vmp is about as high as you should get if you have very cold weather.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • castillojcastilloj Solar Expert Posts: 208
    Re: What equipment needed for solar panels on FX 24v inverter

    I hooked each set of 3 in series and i combined each of the positives from the first panels and the negative from the last panel.
    also the coldest it gets here is about 70/75 degrees.



    MPPT60
    40Amp breaker
    Panel3----Panel3----Panel3
    ....................................................... +++++++++++Panel1----Panel1----Panel 1
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