Inverter choice question: Solar edge 7600A-US vs 7600A-USS

[dcchapman7]

Have recently signed with a company to install a grid tie PV system (8.8 kW Hanwa 340 watt panels) and have the option to choose either a standard Solar Edge 7600A-US inverter or the 7600-USS model for $400 more which is battery back up ready (at least for Tesla Powerwall and LG Chem RESU). I did find other another post discussing this somewhat and tried to learn as much as I could, but am still looking for advice on my particular situation on whether spending the extra money for the battery back up inverter is worth it. I would probably not consider purchasing a battery for at least 5 years...waiting for cost to come down/technology to evolve - my interest in battery storage would be for the following reasons: being able to use power generated and stored earlier in the day during peak times to save money considering if/when the utility company is allowed to keep decreasing the retail value of solar produced and increasing the cost of power consumed from the grid, also considering if grid demand continues to rise and infrastructure is insufficient and more outages occur, would be nice to have battery back up to keep appliance/ a few lights running. So based on this, any thoughts if the extra $400 would be worth spending now as far as additional hardware/connections gained for future battery addition?

[adoublee]

Using the upgraded version would result in a DC Coupled system. I think it is yet to be determined if most all commercially available systems will all end up AC coupled. Tesla has canceled their Powerwall 2 DC coupled version that would work with it in Australia, and who knows when or if they will ever have an available product here.

The other question is if the industry will stay with 48V battery/system or use higher DC voltages like would interface with this. If Tesla ends up out of the game, LG is the only (future in the US) battery left that interfaces with this and they also will have 48V versions. SMA has announced realease of a Sunny Island-like bidirectional inverter for high voltage batteries which is the only other residential power electronics working with high voltage DC (of large manufacturers at least). There are half a dozen or so other "pre-packaged" Li-ion batteries with integral protections that Schneider Conext power electronics should work well with soon, and they are all 48V systems.

I suppose it is a level of insurance, but at this point I think they have had it out and talked about to long without a commercially viable battery that can get connected to it, and the idea of a shared PV inverter might get abandoned for residential systems. Tesla walking away from their product (confirmed in Australia, TBD here when it is more than vaperware) is telling.

[peakbagger]

Sure sounds to me like its "bleeding edge" technology that most likely will be out of date by the time you get around to using it.

My guess is the future is higher voltage home battery packs and possibly inverters designed to tie directly into the battery packs of EVs. There are folks who currently are using Prius's as home power backups and it looks like they all hook up directly to the battery with high voltage DC UPSs from the computer industry. Sure doesn't make sense to have an expensive battery sitting on four wheels in the driveway most of the time and also need one bolted to the wall. Every time you need to convert voltages you inevitably take a efficiency hit and increase the complexity.

[ButchDeal]

The SE7600A-USS is the StorEdge inverter. You can upgrade the SE7600A-US to it. They both use the exact same inverter. If you are not going to even consider a battery for 5 years I would not get the StorEdge, just get the regular SE7600. By the time that you are ready to add a battery SolarEdge will definitely have a new version of the StorEdge.

[dcchapman7]

Thanks for the feedback guys, will hold off on getting the 7600A-USS and stick with the standard inverter.