The Victron BCD 402 2 with 40A DC-performance (MPN BCD000402000) is a diode battery combiner and is used to to supply important consumers with a stable DC-current. Thanks to these diodes this current can come from 2 sources, for example 2 battery circuits.
If one source is not sufficient the second one is used additionally.

Diode battery combiners are used to ensure a constant DC-current for important consumers, for example an electronical motor-control-system. With help of these combiners two or more DC-sources can be connected parallely. If one source is not sufficient or if there is a failure power supply is not interrupted.

Argo battery combiners produce only a very small voltage loss due to the use of Schottky-diodes: voltage loss (low current) at ~ 0.3V and nominal output ~ 0.45V.

Delivery scope:
1x Victron BCD000802000 Victron BCD 802 Diode Battery Combiner 80A DC