Campbell Scientific DCDC18R Boost Regulator - Manual (Page 8)

DCDC18R Boost Regulator
measurement problems because the CR3000, CR5000, and CR23X have star
ground connection at the ground lug. However, unwanted ground loops that
induce single-ended measurement offsets will be generated if the terminals
and the return side of the charging input are tied together because the return
current to the DCDC18R will flow through the terminals.
4
FIGURE 4. Schematic of Charging and Grounding Circuitry
Datalogger LA Base or PS100 Datalogger