Instead of AC coupling/Second inverter on microinverter pv, can this work with battery?

[ajoyce0830]

Is there away to splice into the panels wire before the microinverter and connect that to a battery or bms then battery? That way the dc would stay dc from sun to battery and the microinverter would only invert the dc to ac for the house circuitry. Then of course the battery would have to invert to ac before supplying power to the house, but it could be a separate input, so both sources (pv and battery) would only invert once from dc to ac?

 

[svetz]

Theoretically I think you could do something along those lines... but the cost of connectors, wires, fast disconnects, breakers, surge exposure from extra wire, and SCCs? Probably way more than the inverter loss, for example an Enphase microinverter > 96% efficient.

 

[Ampster]

That is what is known as DC coupling if you do it for the entire DC buss. SolarEdge StorEdge inverters do that in the aggregate. That buss runs at 300 volts and they have partnered with LG Chem and BYD. It is efficient and that is why the first iteration of the Tesla Powerwall did that.
However, as @svetz mentions, it may be ineffcient on a panel basis.