• Each unit’s negative battery connection needs to be connected to the other unit’s negative connections. • Only when the common negative is in place, the RJ45 VE.Bus cables can be connected to the units. • When one unit is taken out of the system all the RJ45 cables needed to be disconnected before removing this unit.
4.6 Shunt
A shunt is needed in a system to measure battery state of charge The shunt is wired in the negative cable. The shunt measures all the current going in and out of the battery bank. Therefore, the shunt needs to be the last item before the battery bank or battery bank bus bar. All DC loads and DC sources need to be connected after the shunt. See on the right how to wire the shunt into a system: The shunt needs to be big enough and should be rated to the maximum DC current that potentially can occur in the system. The battery monitor comes with a 500A, 50mV shunt, but in case the shunt is not big enough you need to add a bigger shunt. Shunts are available in the following sizes: 500, 1000, 2000 and 6000A
When using a bigger shunt make sure that you change the shunt parameters in the battery monitor.
Please be aware that misplacement of the shunt can potentially cause a problem in a system depending how it is wired in. This is especially the case in large systems where there is be a long path between the battery and the inverter/chargers. When inverting, the inverter/charger near the shunt will “see” a lower DC input voltage than the units far away from the shunt When charging, the batteries near the shunt will “see” a lower DC input voltage. Than the batteries further away from the shunt. See below image:
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