Good morning,

if I add a Solaredge battery (DC, directly connected to the Solaredge inverter) to my PV.Sol-project, the produced energy goes down from 8.1 kW to 7.6 kW. I traced that down to the DC/AC-conversion (german DC/AC-Wandlung), which has a loss of 266 kWh without battery and a loss of 665 kWh with the battery.

I do not understand this. The difference between loading the DC-battery and unloading it is just 88 kWh - this I can understand.

Why should there be much higher losses in the DC/AC-conversion, if a DC-battery is added?

Exact inverter and battery used: StoreEdge SExK-RWS + 1 x Home Batterie BAT-05K48 (4.6 kWh)

Hello klausj,
thank you for the request. A common cause of high conversion losses is low utilization of the inverter at night. If a low current is drawn from the battery at night, the inverter that performs the DC-AC conversion is often in the partial load range, which means that it only delivers a low level of efficiency. This can result in high conversion losses. In this case, a simulation with an AC-coupled battery system could be used to check whether the overall losses would be lower.
Kind regards
Mikio