I'm in the final phase of my DIY project (off-grid AIO's but grid as backup if required) and the inspection will be in about 4 weeks. Now I wonder if about the max. allowed solar battery capacity and how accurate an inspector may look about the 20kWh per ESS unit limit.
The EG4-LL-S battery shows 5.12kWh in large letters in front of their cases. I have two battery racks with 4 batteries each which will result in 20.48kWh per rack (ESS) which would exceed the allowed 20kWh per ESS unit. But this will be the case for most LFP batteries which are using 16 cells (most of them do, I only know Pylontech which only uses 15 cells). The nominal LFP cell voltage is 3.2V which will result in 51.2V which will end up in 5.12kWh.
Have someone ever run into this possible problem with inspection? Just want to be prepared.
Not that you're trying to pull the wool over the inspector's eyes, as a knowledgeable individual would certainly know what the full voltage of an LFP battery is, but nominally it
is a 48-volt system, after all, and I would recommend speaking of it as such. When dealing with inspectors (building inspectors and electrical inspectors--but I've never had an experience with inspecting solar yet), I have observed that they are each individuals, and have individual peeves, preferences, and personalities. Some are strict, "by the book" types that will not allow an inch of leeway, and others are more "down to earth" practical. Most have one or two things where they are super strict as compared to other aspects. There's no way to easily predict how an unknown inspector might react, but I could give some general advice:
1) Do not act like you know more than the inspector; be humble, and teachable. A power-hungry inspector seems to derive pleasure from humbling others (especially the know-it-all types), but if they are already humble, there's no more fun in it.
2) Be sure your setup looks tidy. Attention to details and aesthetics, even when they may not be technically/electrically important, goes a long ways toward persuading the inspector that you have done a good job at satisfying the requirements.
3) Depending on the inspector, some seem to think that if they haven't found something to criticize, they haven't done their job. Be happy if the inspector finds some small thing that is easily fixed, rather than looking deep to find something more crucial. If they pull out a tape measure to check the wall fasteners for the wire . . . . well . . . .
An electrical inspector who examined my job of converting an old fuse box for a house into a modern breaker system was very surprised at the nice cover used to cover the old box (which became just a junction box for the wiring that was passed through it and extended to the new breaker box). Removal of the fuse panel had left a large opening in the old cover, if I recall, and it was simply not designed to have that fuse block removed. I had gone to a local shop that worked with sheet metal and the proprietor had manufactured a lid for that old fuse box tailored to the exact size needed to cover it and make it rain-resistant. Seeing that lid, along with my careful work in the breaker box, seemed to satisfy the inspector quickly, and the home was soon reconnected to power. The inspector asked where we were able to get that lid! Being attentive to detail is quite helpful sometimes.
Just my thoughts. Best wishes.
