Use of OFF-Grid-Only AC Coupling with MicroInverters? Good or Bad Idea?
Everybody wants to sell me Grid-Tied. The latest proposal is the subject of this post. The proposed system is for an "off-grid" system that involves ..... an approximately 4500W Array with GT500 Microinverters AC Coupled to a Magnum 4448PAE, a 14kw LifePo4 Battery System, autobacked up by a 3kw or 7kw Honda Generator that is retrofitted to be powered by propane, fed by a 1000+ Gallon Propane reservoir. Any excess power capacity would be fed to a Dump (an unused water heater most likely).
I know that tech has come a long way. I know that these sort of AC Coupled "off-grid" systems have come about largely because "Grid-Tied" system sellers have increasingly met resistance from customers that want to use the generated Solar for Emergency Backup power, and don't understand that when the grid goes down on a traditional grid tied system - so does your solar power. So this has emerged as an increasingly promoted solution..... for TEMPORARY emergency backup into an offgrid situation in the event of grid power outage.
I have done a LOT of reading and research on this, and this is generally what I have found to be concerns, concerns that might also be greatly exacerbated if I were to use this configuration for a 100% Fulltime PERMANENT Off-Grid system.....
- It's overly complex and therefore increases the odds of system failure (including battery damage to overcharge).
- Not only is it complex, it can involve very complicated variable settings, some which may require ongoing tweeking depending on how I am using the system at any given time. (I will have greatly variable use cases - sometimes as a weekender, sometimes full time, and quite possibly as a long term emergency situation if the grid goes down for a lengthy period due to bad actors)
- The added cost is not a justifiable ROI (I also have a full sun roof with no shade issues ever except stray clouds)
I think I know the answer to my own question here, but I am really getting worn down in this process, and want to throw this out to a hopefully impartial group of users for feedback. What are everyone's thoughts on combining AC Coupled Microinverters into a 100% OffGrid system???
PS... also, any separate issues with using it with the LifePo4 batteries?
FYI: my primary goal is to have a solid and reliable system in event of SHTF scenarios. There won't be any technicians coming to the rescue etc.
Thanks in advance.
- david h