Wiring

DC Cables

FIRE HAZARD

Undersized cables can become hot and may potentially catch fire.

Failure to follow these instructions may result in injury.

To create your own cables, use 2/0 AWG (70 mm²) or 1/0 AWG (55 mm²) cables. Attach appropriately sized ring terminals on one end and a HELIOS ESS Terminal Connector (950-0072) on the opposite end. Choose the cables and ring terminals to accommodate the maximum voltage of any circuits sharing the same wiring space. Ensure they are sized to local codes and meet the following requirements.

Copper-stranded cable. DC cables must be stranded, copper, and rated 90 °C minimum. Terminate the cables on one side with lugs that fit the DC terminals on the inverter, and use the quick connect on the other side of the cable for the positive or negative battery terminal.
Minimum and equal cable lengths. Select a location that minimizes the length of battery cables to reduce voltage drop from the impedance leading to reduced performance. If installing multiple batteries in parallel, the length of all the battery cables should be the same.
Appropriate cable gauge. The cables should be capable of carrying the normally expected current, plus a margin of safety.
Proper polarity. Positive (+) is connected to positive (+), and negative (-) is connected to negative (-). Verify the polarity of all connections before energizing batteries.

NOTE

For instructions on connecting terminal connectors to cables, refer to the HELIOS ESS Battery Cable Terminal Connector Set Manual (805-0099).
When selecting the cables for use between the battery and the inverter-charger, note that a single pair of 2/0 AWG (950-0070) cables is suitable for current up to 200 A, and a single pair of 1/0 AWG (950-0071) cables is suitable for current up to 170 A.
The selection between using two pairs or a single pair of cables between the load and the batteries, is based on safely matching the load of the charger (A) and the cable’s maximum current carrying capacity.

DC Protection

FIRE HAZARD

Undersized fuses and disconnects may become overloaded and potentially cause a fire.
Fuses and disconnects are required to open before the cable reaches its maximum current carrying capability.

Failure to follow these instructions may result in injury.

Each battery comes equipped with a 200 A integrated breaker. When multiple batteries are installed in parallel, additional DC overcurrent protection is recommended between the battery bank and load.

Appropriate size. Size the fuses and disconnects following local codes to protect the wiring in the system. The fuses and disconnects are required to open before the cable reaches its maximum current carrying capability.
Install protection. When installing battery protection, ensure the fuse and disconnect are located as close as possible to the battery. Local electrical codes may specify the maximum allowable distance.

This disconnect should be sized to accommodate the maximum expected electrical load of your system. Always consult with your local authority having jurisdiction (AHJ) to correctly size and select breakers that meet all applicable requirements for your specific application.

NOTE

AC circuit breakers and DC circuit breakers are not interchangeable. Check the label on the circuit breaker to ensure it is the correct type and rating. Use only DC circuit breakers.
For non UL installations, the local electrical code in your area may require disconnect switches either in the positive only, or both positive and negative. Refer to your applicable code and check with the authority having jurisdiction to confirm local requirements.

Terminal Connections and Hardware

Plug-and-pull quick connects are used to mate with the plug-and-pull terminals on the HELIOS ESS battery.

Plug-and-pull Quick Connect

Plug the connector into the plug-and-pull terminal.
Gently pull the connector to confirm it is snapped in place.
To disconnect, press the release button on the side of the connector.