optimizers and mismatched modules - take 2

[petect]

Hi I don't know what happened the first post - but here it is again.

I'm going to put up 10 identical modules this spring. The system will be able to draw from the grid, but not put (sell back) power into the grid. ( I'm not sure what to call this type of setup - Xantrex calls it "utility backup mode). As such it will have charge controller(s), an inverter, and a battery bank.

IF I can afford it, I might want to add 2 - 4 more modules at a later date. Occasionally I come across modules locally at a decent price, but they would most likely have specs that are fairly different from the original 10. Can optimizer(s) be used to make the new modules play nice with the originals? If so, how would I do that?
Thanks in advance
Pete

[Mike90250]

Welcome.
First, adding onto a GT system (backup or selling) will generally require a new permit, inspection and agreement EVERY time the system is changed, except for failed parts replacement.

Solar gear does not "scale" well, it's designed for one size. You could overbuild the first time, leaving room and empty conduit space for more expansion, but you have to add another 10 identical panels each time. (short answer. Yes, there are some ways to jigger the panels around and rewire from 10 to 14, to 18, to 22, but you have to plan deeply ahead, calculating string sizes for inverter and pre-installing combiner boxes.
That's more engineering than I'm willing to do for you over the internet.

[ButchDeal]

Is the point of the battery for backup? Or are you hoping it makes it more efficient ( it does not )

the simplest upgrade path is with solaredge, next would be with micros

[petect]

Mike Thank you for the advice.

Butch The purpose of the small battery bank ( 100 ah @ 24 V) is to help with startup loads - fridge, freezer, microwave, etc. The system will be (10) 320W max. modules.

Pete