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9.1.2
Connecting and monitoring midpoint in a 48V battery bank
Due to the voltage drop over the positive and the negative cables the midpoint voltage are not identical.
In an unmonitored battery bank the midpoints should not be interconnected, one bad battery bank can go
unnoticed and could damage all other batteries.
Always use busbars when applying midpoint voltage monitoring. The cables to the busbars must all have the
same length.
Midpoints can only be connected if corrective action is taken in case of an alarm.
9.2 Midpoint deviation calculation
The SmartShunt measures the midpoint and then calculates the deviation in a percentage from what the midpoint
should be.
𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝑡𝑡𝐷𝐷𝐷𝐷𝑛𝑛
=
100 × (
𝑡𝑡𝐷𝐷𝐶𝐶
𝑠𝑠𝑡𝑡𝑠𝑠𝐷𝐷𝑛𝑛𝑠𝑠
𝐷𝐷𝐷𝐷𝑣𝑣𝑡𝑡𝐷𝐷𝑠𝑠𝐷𝐷
–
𝑏𝑏𝐷𝐷𝑡𝑡𝑡𝑡𝐷𝐷𝑏𝑏
𝑠𝑠𝑡𝑡𝑠𝑠𝐷𝐷𝑛𝑛𝑠𝑠
𝐷𝐷𝐷𝐷𝑣𝑣𝑡𝑡𝐷𝐷𝑠𝑠𝐷𝐷
)
𝑏𝑏𝐷𝐷𝑡𝑡𝑡𝑡𝐷𝐷𝑠𝑠𝑏𝑏
𝐷𝐷𝐷𝐷𝑣𝑣𝑡𝑡𝐷𝐷𝑠𝑠𝐷𝐷
𝑑𝑑
=
100 × (
𝑉𝑉𝑡𝑡
–
𝑉𝑉𝑏𝑏
)
𝑉𝑉
OK
WRONG
GOOD
Vbatt+
Aux
SHUNT
