9,300 watts - Two Solaredge inverters or one 7600 watt inverter?

[reader2580]

I am currently installing 6,300 watts of solar on the roof of my detached garage. I am planning to also install 3,000 watts of ground mount solar directly behind the garage in the next year or two. Am I better off with a 7,600 watt inverter today or a 6,000 watt inverter today and another 3,000 watt inverter when I add more solar down the road? (I don't have an issue with my panel being overloaded with two inverters.)

There is a chance the additional solar might never happen so I could be stuck with an oversized inverter for years to come. A 7,600 watt inverter with 9,300 watts of solar attached is almost certainly going to clip at some point, but I don't know how often that might be.

Upgrading from a 6,000 watt to 7,600 watt inverter would cost about $300 versus $1,000 for a 3,000 watt inverter in the future.

[sensij]

A single 7600 W inverter will be challenging if you install the ground mount later. 6300 W is more than you can put into a single string, even on the 7600H, which allows up to 6000 W (no more than 25 optimizers) max. The data sheet indicates only 1-2 strings are allowed, so if you use two strings for the roof, you'd have to figure out how to tie one of those strings in series with the ground mount later.

(I wouldn't be worried so much about the clipping, that alone isn't going to justify the $700 in additional cost for two inverters.)

[reader2580]

I didn't pay enough attention to the technical details on the inverters previously. You are only allowed 5700 DC watts per string for Solaredge inverters except the SE7600H which can be up to 6000 DC watts. I will need two strings for my 6,300 watts on the roof.

It looks like it makes sense to have two separate inverters.

[GRickard]

...or you could go with the SE10000. I believe it allows for three strings.

Greg

[reader2580]

The cost on the SE10000 is such that it would be about the same cost as two inverters. It would also be way overkill to start with for 6,300 watts.

[sensij]

Putting the ground mount in series with one of the rooftop strings might not be such a big deal if you plan for it. What are you using, 300 W panels? Make the roof a string of 8 and a string of 13. Size the home run for the short string to account for the extra length that will be in the circuit eventually.