Parallel Battery Installation

FIRE HAZARD

Use cables that meet specifications. Undersized cables can become hot and may potentially catch fire.

Failure to follow these instructions may result in injury.

Batteries used in a parallel system must meet the following requirements:

Same model. Batteries must be the same model.
Equal voltage. The battery has a Pre-Charge System that allows you to connect batteries at different SOC. The best practice is to confirm batteries are within 50 mV (0.05 V) of each other before installing them in parallel.

Cables interconnecting the batteries must meet the following requirements to optimize performance:

Minimum cable length. Select a location that minimizes the length of battery cables to reduce voltage drop from the impedance.
Equal cable gauge. The interconnection cables should be the same gauge.
Equal cable length. The interconnection cables should be of equal length.
Connectors. Battery terminal connections require specific connectors. Refer to the “HELIOS ESS Accessories For Parallel Installation” section.

Install equipment following the standards set by the local authority having jurisdiction. The following instructions assume the battery and inverter have been attached to the wall.

NOTICE

EQUIPMENT DAMAGE

Avoid short circuits. Short circuits will damage the battery and void the warranty.
Failure to securely lock the ends of battery cables to the receiving pins on the battery will increase resistance and lower voltage, leading to burnout of the terminals and voiding of the warranty.
Some inverter-chargers support temperature-compensated charging. Disable temperature compensated charging on the charger or inverter.
Do not use or install a battery temperature sensor.

Failure to follow these instructions may result in equipment damage.

NOTE
To connect HELIOS ESS batteries in parallel, use busbars, the HELIOS ESS Parallel Wire Kit (950-0068), or create your own appropriately-sized cables with the HELIOS ESS Terminal Connector Set (950-0072).