Overview

The Victron Energy ASS070400100 is a pre-charge cable for bringing the DC input capacitors of an inverter, inverter/charger, or MPPT solar charge controller up to battery voltage before the main battery positive connection is made. On a boat, that matters when commissioning or servicing a high-current DC system, because connecting a charged battery bank straight into empty capacitors can create arcing at the terminal.

This cable is used as a temporary installation and service tool, not as a permanent battery lead. The battery negative is connected first, the main positive cable is left disconnected, and the pre-charge cable is connected between battery positive and the device positive input. The yellow LED stays on during pre-charge and turns off when the device has reached battery voltage. A red LED indicates reverse polarity, so the cable should be disconnected and reconnected correctly before continuing.

For a MultiPlus-II 48/5000, pre-charge can take less than a second, while larger inverter systems may take longer. In higher-capacitance systems the cable can draw up to 0.5 A while connected, so it should be removed after pre-charge and followed immediately by the main positive battery connection.

Key features

• Pre-charges the internal capacitors of Victron inverters, inverter/chargers, and MPPT solar charge controllers through the DC terminals before the battery is fully connected.
• Helps prevent arcing at the battery connection point during commissioning, battery replacement, or DC system service.
• Yellow LED shows that pre-charge is in progress and turns off when the connected device has reached battery voltage.
• Red LED indicates reverse polarity, giving a clear check before the main positive battery cable is connected.
• Useful for larger onboard Victron systems, including installations with MultiPlus, MultiPlus-II, Quattro, or Quattro-II units.
• Can be used for systems up to a 3-unit MultiPlus or Quattro installation; larger systems may require parallel pre-charge cables or one-unit-at-a-time pre-charging.

Installation and use

Use this cable during installation, recommissioning, or service work on the DC side of a Victron power system. It is especially relevant on vessels with sizeable battery banks, lithium battery upgrades, inverter/charger installations, or solar charging systems where the DC connection may be opened and reconnected during work in the electrical locker or technical space.

The normal sequence is to connect battery negative first, leave the main positive cable disconnected, then connect the pre-charge cable from battery positive to the positive input terminal of the inverter, inverter/charger, or MPPT. Once the yellow LED goes out, remove the pre-charge cable and complete the main positive connection without delay.

System fit

This is a practical tool for installers, boatyards, and owners working with Victron DC power equipment. It is not a substitute for correct fusing, isolation, cable sizing, torque settings, or battery manufacturer procedures, but it helps make the final battery connection cleaner and safer when capacitors inside the connected equipment need to be charged first.