Shunt resistor right application?

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SUMMARY

The discussion centers on the application of a current limiting resistor to manage current surges from a 400A (125VDC) charger when reconnecting a battery bank. The proposed solution involves placing a properly sized shunt resistor between the disconnect switch and the DC panels to mitigate voltage drops during the surge, which could reach approximately 350A. The resistor should be sized according to the ##I^2R## loss and removed from the circuit after the surge has passed. The use of an inductor for surge limiting was deemed ineffective due to the slow response time of the battery.

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whodatnation
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I have a 400A (125VDC) charger that feeds a battery bank and a few DC panels (critical). This poor design has the panels being fed from the high side of a 600A breaker that is between the charger and battery bank. I need to take the battery off line for a load test but the problem I'm going to have is when I reconnect the battery to the charger I will have a current surge coming from the 400A charger to the unenergized battery bank (approx. 350A). This will most probably cause a voltage drop in the DC panels which I CANNOT have (critical loads on panels). Will a proplerly sized shunt resistor between the disconnect switch and panels work for this situation?
 
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Yes. I would not call it a shunt, I would call it a current limiting resistor. It needs to be sized for the ##I^2R## loss. Then it should be shorted once the surge has passed to remove it from the circuit.

I was thinking about an inductor for surge limiting, but no that would not work because the battery would be too slow to respond, making the surge last for seconds.
 

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