parallel and series 10 solar panels

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

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

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

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