With the Duracell 5+ if working with an RAI inverter Ferrite loops are required to prevent this. This will be installed both on the DC power cables within the same Blue Loop (5xloop positive and 5 x loops Negative) as close to the inverter as possible.
Also required, are the 2x small black ferrite loops, place these on top of each other and wrap the Comms cable 5x through the loop, again as close to the inverter as possible.