I have a small roof that barely fits 12 panels, a row of 8 in portrait on top, and a row of 4 in landscape below. The 4 will get some shadow on the bottom for about 4 months of the year, so they would need to go on a separate string ideally, however 4 panels is too few for most inverters wit double MPTT's.
For this reason I have been looking at these micro inverters:
Another feature that I would like is readily available on many cheap (hybrid) string inverters. An EPS (Emergency Power Supply) back-up feature that is intended to power the refrigerator and some lights (no heavy load) when the grid goes down. For example the Growatt SPH series.
With micro-inverters I could compensate by running the refrigerator and freezer on a regular UPS (usually used for computers, giving them time to shut down), for example from APC. However this will only last a short time since the micro-inverters will not feed the UPS.
Enphase has an extremely expensive solution, that ties you in to using their products, and another thing that rules them out is that providing internet to their system is almost compulsory in order to get it up and running or to clear a fault detection. I'm not planning to give them access to my NAS or allow packet-sniffing on my internal network any time soon.
AP-systems just say they do not support any back-up system at this time in their FAQ.
APsystems’ microinverters are designed to be grid-tied only. APsystems does not support using microinverters in conjunction with a generator on a closed-loop system. The APsystems warranty policy clearly states that microinverters used with a generator are not covered.
NEP does not mention back-up at all.
If I shut off the grid and all breakers except for one, (in fact shut off the whole house except a few outlets on the attic). Could I use a Power Station (portable battery inverter), for example like this one, to trick the micro inverters into delivering power again? Yes I know I would have to come up with something safer than a suicide cable, and that it would void APsystems warranty, but when the dikes are broken and I'm confined to the top floor I would not mind.
The question is, would it work? Which one would work best (AP / NEP)? Has anyone tested it?
If not I'll probably look for a small hybrid string inverter for the top 8 panels and Microinverters for the bottom 4...