Add 4 panels in parallel to 1 panel in my solar array?

[SunEagle]

Just a wild guess based on his first post, it sounds like he has 72 cell panels that he's been told are "24V" panels, and he's wired ten of them in series for what he thinks is 240V, and has paralleled two such strings. Now he plans to put four more panels in parallel and put those across one of the panels, thinking that will increase the wattage of that string. If he'd answer the questions we could make sense of this, but his refusal leaves too many unknowns and nothing to go on to guide him toward a better solution.

I would say that the OP's attitude about not wanting to let the POCO know about the additional panels means they do not care about following the law or code.

I say **** him and let him do what he wants and if the system dies then let that be a lesson.

[TKB4]

To directly answer your question. It depends on the specs on your current inverter and if the inverter can handle it then the rating of the wiring currently in place.

All systems of solar panels produce a different number of watts per string at different times from things such as shading , clouds, snow etc. the difference is the mismatch would be augmented by what you suggest.

Remember since it is a grid tied system then most likely the panels are connected in series in each string so about 240v per string. It seems as though you may know that and are trying to get more wattage on one string but keep volts same and increase amperage. I still don't understand why you would want to add all 4 panels to just one string unless its just more convenient for locating panels or shorter wire runs etc.

SDOLD has a point and the information would help give a much more concrete answer.

Sorry saw where he posted while I was typing my post but will post anyway.

[sdold]

Remember since it is a grid tied system then most likely the panels are connected in series in each string so about 240v per string.

This is why it's important to answer questions when you are seeking help on a forum. When someone says a "24V" panel they usually mean a 72-cell panel that would operate at around 35V with an MPPT controller, not 24V. So if he series-strings ten of these "24V" panels together on a grid tie inverter the panels will operate at 35V each or 350V. However if the grid goes down or fails to satisfy the inverter and it goes offline, the panel voltage could go to its open-circuit value of maybe 45V, or 450V for the string. He could add his four panels to his two series strings for a total string voltage of 420V operating or 540V (or more) open-circuit, which is getting up there. In cold conditions it could go higher, and might exceed the inverter max voltage spec.

[jflorey2]

I have a solar array of 20 230w 24v panels for on grid use. There are 2 groups in series to make 240vdc. I also had 4 of the same panels powering my barn. But, due to various machines using more power, I can no longer power my barn with those 4 panels. I was wondering if I can splice these 4 panels into my 20 panel array. The only way I think I could do it would be to splice all 4 24v panels in parallel to one panel in the array. But, that would mean one of my 240v groups would be the same 240v, but would produce about 1000 watts more than the other. Can I do this?

No. If you just parallel 4 of the panels in your 10-panel string, you will get no more power out of it. You'd need to add 10 more panels to get another string. However at that point you'd likely exceed the string's current limit.

My suggestion would be to contact a solar installer or electrician, tell him you've got 4 extra panels and you want to install them to increase your output. Using four Enphase inverters is a good way to do this, and it's not hard to do.

[Ampster]

......... Using four Enphase inverters is a good way to do this, and it's not hard to do.

That is a good way to add incremental capacity especially if you don't want to complicate an existing system that is under warranty. I recently acquired some used panels that I put on a west facing patio cover and ran a circuit to a breaker and wired up the panels. The building permit was the hardest part.