CSL500 Instructions

Current Surge Limiter (CSL500) -INSTRUCTIONS
The CSL500 Current Surge Limiter is FET-based current limiting device that is to be used with Battle Born
Batteries or Dragonfly Energy LiFePO4 battery packs when they are used in conjunction with large
(greater than 4kW) inverter/chargers. The device is mounted permanently in series between the
negative pole of the battery bank and the negative DC input terminal of the inverter/charger. The device
protects the battery management system (BMS) from damage caused by the initial current spike that is
created when connecting directly to the large capacitors (> 5 milliFarads) that are typically on the DC
input side of the inverter/chargers. The device allows the batteries to slowly charge the capacitors
(within 1 ms). This soft start avoids the high-current shutoff inherent to the BMS of the batteries.
First, the negative battery terminal is connected to the brass bolt mounted on the thin
Aluminum plate that is in contact with the circuit board on the device.
Second, the DC input to the inverter/charger is connected to the brass bolt directly connected to
the large Aluminum heat sink on the opposite side of the device. Note that both of these
connections will pass the full current of the system, and therefore the cable and lug sizes must
be selected accordingly. The CSL500 is designed to accommodate a continuous current of 160A.
Finally, the third connection is made between the positive DC input of the inverter/charger to
the smaller stainless steel terminal located on the thin Aluminum plate. This connection is only
meant as a power source for the FETs on the circuit board and the connection cable can be
smaller (16 awg is fine).
48V Wiring diagram:
Note: Either the negative battery terminal OR the negative DC input to the inverter/charger should be
connected to an earth or chassis ground. NOT BOTH! Connecting both to ground will bypass the device.

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