parallel and series 10 solar panels

fvrdbauer
fvrdbauer Registered Users Posts: 8
I have 5 200 watt solar panels(all MC4 connectors) in a series now. I have a MPPT 60 charge controller,I would like to add 5 more panels in a parallel to get the amps. Do I just parallel them to together and run seperate positive and negative wires to my charge controller and batteries? I cant imagine you would series one set and parallel another and Y them together.Can anyone give me some advice on what to do.

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: parallel and series 10 solar panels

    I am not quite sure I understand your question...

    In theory, yes, you can just parallel the second string of 5x 200 watt panels to the first string and either connect them to the same charge controller, or to a new MPPT charge controller that runs its output cabling back to the battery bank (it is perfectly OK to have two or more charge controllers in parallel on one battery bank). If the charge controllers do not have a "syn" cable/setup--they may not change states (bulk, absorb, float) at the same time--but it will not hurt anything.

    Now the details... Really need to now the Vmp/Imp of the solar panels, the battery bank voltage, Brand/model of MPPT charge controller, and where you live/using the system (i.e., Death Valley or up in the Yukon--panel Vmp changes with ambient temperature).

    Fusing, Breakers, Wiring, battery bank voltage and Amp*Hour capacity, etc., all matter when trying to make for a safe and effective installation.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • fvrdbauer
    fvrdbauer Registered Users Posts: 8
    Re: parallel and series 10 solar panels

    vmp is 18.1 , imp 11.05 I live in the middle of ohio i have 5 panels already in a series and I just installed 5 more in a parallel but for some reason it didnt work when I put them in a y then run it to the charge controller. the charge controller is Xantrex MPPT 60 it can take up to 150 Volts. 5 in series is about 100volts the parallel would be around 20 volts . In theory I thought I was right but now Im not sure.
  • fvrdbauer
    fvrdbauer Registered Users Posts: 8
    Re: parallel and series 10 solar panels

    The whole system is xantrex the xw6048 hybrid inverter and charger and the mmpt 60 the battery bank is 48v
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: parallel and series 10 solar panels
    fvrdbauer wrote: »
    vmp is 18.1 , imp 11.05 I live in the middle of ohio i have 5 panels already in a series and I just installed 5 more in a parallel but for some reason it didnt work when I put them in a y then run it to the charge controller. the charge controller is Xantrex MPPT 60 it can take up to 150 Volts. 5 in series is about 100volts the parallel would be around 20 volts . In theory I thought I was right but now Im not sure.
    OK--Regarding the panels, you started with:
    [FONT=Fixedsys]
    [   charge   ] positive ----[p][/FONT][FONT=Fixedsys]----[p][/FONT][FONT=Fixedsys]----[p][/FONT][FONT=Fixedsys]----[p][/FONT][FONT=Fixedsys]----[p]-+
    [            ]                                              |
    [/FONT][FONT=Fixedsys][ controller ] negative ------------------------------------+[/FONT]
    
    
    Then the second string:

    [FONT=Fixedsys]
    [   charge   ] positive---+-[p][/FONT][FONT=Fixedsys]----[p][/FONT][FONT=Fixedsys]----[p][/FONT][FONT=Fixedsys]----[p][/FONT][FONT=Fixedsys]----[p]-+
    [            ]            |                                 |
    [/FONT][FONT=Fixedsys][ controller ] negative-+-----------------------------------+
                            | |
                            | |
    [/FONT][FONT=Fixedsys]                        | +-[p][/FONT][FONT=Fixedsys]----[p][/FONT][FONT=Fixedsys]----[p][/FONT][FONT=Fixedsys]----[p][/FONT][FONT=Fixedsys]----[p]-+
                            |                                   |
                            [/FONT][FONT=Fixedsys]+-----------------------------------+[/FONT]
    
    
    The above would be how you would connect two 5x series strings in parallel for Vmp~100 volts.

    If you have to Xantrex MPPT Charge controllers, the second string would connect to the Vpanel inputs of the second controller.

    Because of the way the Xantrex MPPT 60 amp controller is designed, no other connections shall be made between Vpanel+ and Vpanel- ). No ground connections, no sharing panel array connections between two different controllers).

    Given that this is a 60 amp controller on a 48 volt battery bank, you can connect around 3,600-4,500 watts or so worth of panels without any issue (assuming wiring, fusing, breakers, battery bank, etc. are all properly sized for the installation--as always, follow the manual).

    You don't want to operate the Vmp nominal voltage much above 100 VDC (rated Vmp)--On cold days, the Vmp/Voc rise and can exceed 150 VDC, voiding the warranty and possibly damaging the charge controller.

    You can use the Xantrex XW sizing website to ensure that your panels and local temperatures are safe for your configuration.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • fvrdbauer
    fvrdbauer Registered Users Posts: 8
    Re: parallel and series 10 solar panels

    Thank You so much for your help. For some reason Im not understanding the diagram you made, can you explain it to me?Heres what I have; a series of 5 panels pos neg and so on on 1 string. The second string I have 3 pos going into MC4 X connector coming out of the MC4X into another MC4 X and adding 2 more panel then coming out of that to the Y connector where the series panels are,same with the neg. side. Maybe I should of put all 5 pos together into one and all 5 neg together into one instead of using the MC4 X connectors ?The panels Im using are 200 watt evergreen.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: parallel and series 10 solar panels
    fvrdbauer wrote: »
    Thank You so much for your help. For some reason Im not understanding the diagram you made, can you explain it to me?Heres what I have; a series of 5 panels pos neg and so on on 1 string. The second string I have 3 pos going into MC4 X connector coming out of the MC4X into another MC4 X and adding 2 more panel then coming out of that to the Y connector where the series panels are,same with the neg. side. Maybe I should of put all 5 pos together into one and all 5 neg together into one instead of using the MC4 X connectors ?The panels Im using are 200 watt evergreen.

    There's your problem: you can't have one string where 5 panels are connected in series and another string where they're connected in parallel. You need two strings where 5 panels are connected in series, then connect the two strings in parallel.

    Bill: I'm thinking some basic wiring diagrams/schematics would be a good addition to the FAQ's. This sort of question comes up often.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: parallel and series 10 solar panels

    As Marc says, with series/parallel connections--The series connections add up voltage, so any additional panels have be connected in strings of 5 series too... The output voltage of each string needs to match all the rest of the strings for energy to flow properly.

    Otherwise, the highest voltage string will simply supply all of the current, and the other, lower voltage string, will simply not supply any power/current at all.

    Imagine you have a 5 cell flash light with 5x D batteries in series (5x1.5 volt = 7.5 volts). If you try to connect any other combination of 5 cells (3 in parallel, two in series--then connect all to the first string of 5x cells in series)--those batteries will be outputting less voltage, and they will not add any power/capacity to power the light.

    Try this link and see if it helps. Note that solar panels are a very different sort of battery and behave differently that if you put the wrong combination of series/parallel panels together.

    Real Batteries will actually try to charge the lower voltage string of batteries (and discharge the higher voltage set). Solar panels have blocking diodes and the lower voltage string will simply not supply/consume any current--just like the lower voltage strings are not there.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • fvrdbauer
    fvrdbauer Registered Users Posts: 8
    Re: parallel and series 10 solar panels

    Thank you so much for the info, I do understand it now 2 series then parallel together. It would be nice to see the wiring diagrams on the page for beginners like me;you guys are great. Can you tell me how these should be wired in a series of 5 each . I pretty much can understand 4 panels but not understanding the 5th panel. If I series one array(all 5 panels) and series the second array then parallel them together what would my max volage be. The mttp 60 is a maximum 150 volts. according to xantrex you can have a total of three arrays per mttp60. These panels are 18.1volts. If 5 panels wired in a series is producing between 18 to 22volts ranging about 100volts. And I wired the second array the same way having the same voltage and I parallel them together what would my voltage be? would it be still at 100 or would it double with the 2 series paralleled together? and after all this do I even need a combiner box sense everything just plugs in with the MC4 connectors
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: parallel and series 10 solar panels
    fvrdbauer wrote: »
    Thank you so much for the info, I do understand it now 2 series then parallel together. It would be nice to see the wiring diagrams on the page for beginners like me;you guys are great. Can you tell me how these should be wired in a series of 5 each . I pretty much can understand 4 panels but not understanding the 5th panel. If I series one array(all 5 panels) and series the second array then parallel them together what would my max voltage be.

    When you parallel your two solar panel strings, the array voltage does not change--but the array current into your controller will double.
    The mttp 60 is a maximum 150 volts. according to xantrex you can have a total of three arrays per mttp60. These panels are 18.1volts. If 5 panels wired in a series is producing between 18 to 22volts ranging about 100volts.

    That is correct--but we really need to know the brand name and model number of your panels--and then we can plug that information into the Xantrex/Scheider XW MPPT charge controller configuration website.

    The calculations are complex enough that it is usually easier (and less prone to errors) to use the website directly.

    There are minimum and maximum voltage limits, and inter-related current limits too.
    And I wired the second array the same way having the same voltage and I parallel them together what would my voltage be? would it be still at 100 or would it double with the 2 series paralleled together? and after all this do I even need a combiner box sense everything just plugs in with the MC4 connectors

    Again, the voltage (when paralleled) would remain the same, but the current will add and, in this case, be double that of a single string.

    You don't need a combiner box (with breakers or fuses) for 1 or 2 paralleled strings of solar panels. However, for safety requirements, when you have 3 or more strings in parallel, then you need a series protection fuse (or breaker) in series with each string to prevent a short somewhere causing a fire (in panel or wiring).

    Many people add a combiner box/breaker even with 1 or 2 strings so that they can have an on/off switch for the solar array to do maintenance and debugging (see that each string is producing an equal amount of current). Also, you do not want to plug/unplug MC4 while there is current flow. The arc may damage the connectors if they are opened/plugged under load.

    Vmp=100 volts is getting pretty close to a safe maximum for a 150 VDC controller in cold weather... The real problem is Voc (cold)--which is higher than the 18-22 volts of Vmp.

    Xantrex XW sizing website

    Again, with the panel brand and model numbers, we can use the website to confirm the configuration for your area.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • fvrdbauer
    fvrdbauer Registered Users Posts: 8
    Re: parallel and series 10 solar panels

    Thank You again the panels I have are evergreen 200 W 18.1 v 11.01 amp
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: parallel and series 10 solar panels

    Assuming they are Evergreen ES-200-fa3 panels (the other 200 watt is almost identical)--From the website, assuming 100F max and -20F minimum (you have some very low record low temperatures)--You can put either 4 or 5 panels in series to charge a 48 volt battery bank (properly).
    [FONT=Fixedsys]Max VOC at Min Temp     
    Min VMP at Max Temp
    (cell temperature 35°C)
                  Voc Cold      Vmp Hot
    4 Modules     106 Vdc       59 Vdc*
    5 Modules     132 Vdc       74 Vdc  
    * Indicates nearing min or max Vdc [/FONT]
    
    One string of 5 panels will give (PTC--realistic ratings) into a 48 volt battery bank:
    • 914 Wdc or 16 Adc
    Two strings of 5 panels each (10 panels total) will provide:
    • 1828 Wdc or 33 Adc

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset