Connecting more panels to an existing array

[Oliver in Spain]

I wish to add 2 sets of two 455w panels to an existing array of 2 sets of six 455w panels. The inverter has spare capacity though I wish to orientate the 2 new sets (3&4 in the image) to take more advantage of morning and evening sun respectively.
Can I just wire the 2 new sets into the existing circuits or do they need diodes or something?
Thanks in advance.
Thanks in advance

 

[Bobert]

your picture shows 6 panels in series 2 and 2 sets of 2 panels in series all combined in parallel. There are several problems with this arrangement number one if you have more than two strings in parallel they must be fused in between each string. Also having different voltage between your strings will result in the lower voltage panels essentially producing nothing to the entire array possibly even draining The output of the entire array. Placing diodes in the correct places might possibly prevent draining the larger array to the smaller array but it will not make the smaller array produce power which it essentially will not do in the arrangement that you show. The smaller arrays will simply produce a little to nothing. Advising you on how to arrange your solar panels is virtually impossible without knowing the specs of your charge controller as well as all the specs of your solar panels.

 

[Oliver in Spain]

your picture shows 6 panels in series 2 and 2 sets of 2 panels in series all combined in parallel. There are several problems with this arrangement number one if you have more than two strings in parallel they must be fused in between each string. Also having different voltage between your strings will result in the lower voltage panels essentially producing nothing to the entire array possibly even draining The output of the entire array. Placing diodes in the correct places might possibly prevent draining the larger array to the smaller array but it will not make the smaller array produce power which it essentially will not do in the arrangement that you show. The smaller arrays will simply produce a little to nothing. Advising you on how to arrange your solar panels is virtually impossible without knowing the specs of your charge controller as well as all the specs of your solar panels.

Thank you Bobert. The idea was just to add the 2 new pairs of panels in parallel as an easy fix. The initial installation I fitted in March and is providing sufficient power - my fear was that as winter sets in there may not be enough production and thought this may be an easy fix. Obviously not. I will see how this winter shapes up before making a decision on whether more are needed - it was just an idea. Many thanks for your advice and help.

 

[TomC4306]

2 options.
Get 5 new panels and add as a 5s string oriented however you wish and paralleled to the existing arrays.
Or, get a separate charge controller for the 2s2p panels.
Do not connect dramatically different voltage series strings in parallel to the same charge controller.

Edit. Yor text says 6 panels in a string but the drawing shows 5.
If I was you I would add one more string identical to what you already have. In parallel.

 

[Bobert]

2 options.
Get 5 new panels and add as a 5s string oriented however you wish and paralleled to the existing arrays.
Or, get a separate charge controller for the 2s2p panels.
Do not connect dramatically different voltage series strings in parallel to the same charge controller.

Edit. Yor text says 6 panels in a string but the drawing shows 5.
If I was you I would add one more string identical to what you already have. In parallel.

Another possibility would be to divide up the panels and end up with 3 series strings in parallel. It depends on the specks of your charge controller and the practicality of the rewiring.

 

[Texas-Mark]

Another possibility would be to divide up the panels and end up with 3 series strings in parallel.

Can't he just get two more panels (for 6S) and add as a third parallel string (controller rating permitted)?