Adding more solar panels to an existing SolarEdge system

[DaveC_Napa]

Hello,
I had a local Solar company install a 5.9kW system on my roof a year ago.
My inverter is a Solar Edge SE7600H-US.
It was my plan all along to add more panels. When I contacted them recently to add 4-5 more panels, they quoted me a price of $5k !! I spent about $1,200 on materials.
So I went out and bought the panels myself and have them installed on the roof. I am ready to connect them in series with an existing panels.

If I just connect the additional panels, will they work and my system create more power?
I recall reading how there is a system configuration button on the inverter that causes the inverter to go read the serial numbers of all inverters connected.
is this necessary?
Any knowledgeable help is appreciated.

Thanks, Dave

[Ampster]

Do you know if your system is currently configured as one or two strings? With that information you may want to go into the string sizing tool on the SolarEdge website and see if adding more panels would require a change in strings. Before disconnecting or reconnecting any panels, be sure and turn off the DC switch to avoid arcing the connectors.

In the end, you will want to run the configuration utility to configure the system for the new panels and Optimizers.

[DaveC_Napa]

My system is configured in 2 strings.
I learned something interesting on that subject. one string consists of 10 panels on the garage roof facing south.
the 2nd string is split between 4 panels facing south on the garage roof, and 5 panels on a the west facing roof.
Before the 2nd string starts producing power, all of the panels facing south and west need to have the sun on them. That makes the 4 facing south on the garage roof produce less power every day.
I am going to rewire the strings to have all of the south facing panels on one string, and all of the west facing panels on the 2nd string.

I know to turn off the DC switch before making any wiring changes.

thanks.

[Ampster]

...........
I am going to rewire the strings to have all of the south facing panels on one string, and all of the west facing panels on the 2nd string.
........

That sounds like a good plan. I think you can model that on PV Watts to some degree. One thing the west facing string will give you is more revenue at the higher rates during peak hours. What you were probably seeing with the old configuration was that the strings were not getting minimum voltages until the sun shined on all of them.

[hardwired]

Do yourself a favor and download the Solaredge Designer tool and put your current configuration in. Then add or modify strings. There's a minimum number of panels on a string and there's a maximum amount of wattage on each string.

https://www.solaredge.com/products/installer-tools/designer

It looks like on the 7600 mode your limited to 5250W per string so 10,500W total.
I believe you will need to know the bar codes on the new optimizers to add them in. Do you have the codes for the current installed ones? Not sure if they have to be listed in physical sequence but I'm guessing probably.

[RaulM99]

Dave,

Did you successfully add panels to your system yourself? I myself am interested in adding panels if possible. I have the same SE7600 with two strings of 9 panels currently and would like to add 2 panels per string. If you were successful, did you follow a guide that you can share. Thank you.

Raul

[Ampster]

............... I myself am interested in adding panels if possible. I have the same SE7600 with two strings of 9 panels currently and would like to add 2 panels per string. .......

I know your question was directed at Dave but I recently added 4 panels using micro inverters because I did not want to mess with the existing Solaredge system that was under warranty from the installer. All it took was a building permit, an addditional circuit breaker and some wire. I did not have to ask my power company because they allowed me to add 1kW without going back through a new NEM agreement. At least in California the 1kW exception is pretty common. You should verify how it applies in your situation.

[hardwired]

Dave,

Did you successfully add panels to your system yourself? I myself am interested in adding panels if possible. I have the same SE7600 with two strings of 9 panels currently and would like to add 2 panels per string. If you were successful, did you follow a guide that you can share. Thank you.

Raul

Hi Raul,

What panels are you using and what's the current total watts. How many max peak watts is your system producing on cool sunny days?

I would go with more than 4 Panels if you can fit it and there not impacted by shade or some utility limit. Maybe 8-10 depending on what your generating now.

[djme1l2e]

Dave, did you ever get your extra panels added? I'm trying to do the same. I have them hooked up and added the optimizer numbers but my inverter is still only showing the original but my layout shows all of them.

[warx]

I'm in the same position. I have 7600 StorEdge with two strings of 10 and 11. I have three more panels and optimizers to add. If I add them to the strings but do not commission the optimizers (I don't have installer access to the portal - just end user simple phone app) will they produce anything or do they just remain in SafeDC mode?

Likewise, I have a warranty concern but since I have the optimizers I would like to try to get them on the SolarEdge system so they'll work with the batteries too. If I leave as a separate system at 3x350W I suppose it makes sense to buy 3 x microinverters rather than any sort of small 1kW string inverter.

[warx]

Well, to answer my own question; I ordered three Enphase IQ7 instead and will sell the P370 optimizers. SolarEdge really does a good job of protecting their setup. Hoping to avoid the Envoy system with such a small setup. I can do basic monitoring via an Emporia at tie-in.

[Ampster]

That is the easiest way to add a few panels to an existing string inverter system. As I mentioned earlier in this thread I did the same thing a couple of years ago. I am now in a new home and have an all micro system facing SE.

I am going to add some west facing panels to supplement my SE facing system. I also have an Emporia and if your Solaredge system is on the Emporia you could just thread the lead from the new system through the Emporia CT.

[scrambler]

Ampster Glad you went for the Emporia, this is such a great monitoring system!!

[Ampster]

Ampster Glad you went for the Emporia, this is such a great monitoring system!!

Yes, I need more CTs but will start combining some small circuits because more CTs is not an option. I have my two sub panels fed through a big 6x6 wiring gutter so doing that is easy. I put circuit numbers on everything. I have gotten some weird results and am wondering if I need to pay attention to L1 and L2 when combining 120 V circuits through one CT. I understand about a factor of 2 when only putting CT on one leg of 240V circuit.

[warx]

Emporia has some limitations. My grid in is via two dual breakers (2x2x100A). i.e. each of L1 and L2 has two 1/0ga cables. Clamping a 200A CT on one of each has given me decent results assuming the same cable stock and each of the same phase is simply sharing the load. Sometimes it's way off. If the Vue had four 200A circuits it would work for me. This also messes up any SolarEdge CT option too - it can only do a single pair for grid in.
My panel gets more complicated as there's a 100A CB to the SolarEdge backup interface and a 100A connection back that goes to two sub panels for backed up loads. That leaves the EV, A/C, spa and my 6-50R welder socket on the main panel. The Vue can't handle 100A CTs but supposedly is ok to 63A or so.