Generators will be banned in California so i will switch to battery backup. i came across EG4 inverter has UL1741 rating. searched youtube but did not find any solid reviews on AC coupling with IQ8's. couple people have tried with solark which is very expensive to even give it a try.
worst case i will have EG4 inverters and batteries with out PV.
EG4 has only 1 grid-tied UL1741SA hybrid inverter. This inverter cannot AC couple in a micro grid! UL1741 SA means that the inverter can be grid-tied and that it is able to "follow" what the utility generator requires, but the inverse/mirror or ying for yang is not possible. In the micro-grid case, the inverter takes on the role as the main generator and must provide similar UL1741 SA functionality as the grid generator. The EG4 hybrid inverter cannot do this. The EG grid-tie hybrid inverter has a 48V backup battery, but requires a high voltage DC PV string to charge the batteries in off-grid mode. If you have room for a small additional PV array, it could be an option. Caution: you need to disconnect the PV feedback if operating in backup mode!
Depending on your needs, the lowest cost solution is an off-grid inverter with a battery bank, setup as a generator look-alike and feeding into a generator equivalent inlet. You need a generator breaker with a UL listed mechanical interlock on the main breaker panel, if allowed by your local jurisdiction. If you use an inlet and a generator plug, then the backup system does not need a building permit, but please check with your local authority. But once you drain your batteries you need power to recharge them and you cannot get it from all the IQ8's you have!
There is pressure building on Enphase to get IQ8 AC coupling to work! The more it gets publicized that it doesn't work and that prior working IQ7 AC coupling may not work anymore, the more pressure there is to get Enphase to fix it. My suggestion: wait for it and don't rush to buy an expensive Enphase backup solution!
If you cannot wait or postpone the implementation, then look at FranklinWH. Put IQ8 compatibility in writing and be ready to spend 10k and more.
Enphase will come out with a better ESS battery, 4kW inverter and 5kWh energy and hard-wired interconnection later this year, but all the other overhead like load panels will drive up cost. And the thermoplastic enclosures are not the best choice for a wild-fire prone area, they melt at 320 degree! If located outside, you are much better off with all-metal panels!
