“Parallel configuration of Gen2 and Gen3 Lithium batteries”

“Parallel configuration Gen2 and Gen3 Lithium batteries”

Enerdrive-Dometic Compatibility Statement

Enerdrive-Dometic confirms that there are no issues connecting Gen2 and Gen3 Lithium batteries in a parallel configuration, provided that all steps outlined in the Best Practice Guidelines are followed before configuring and powering on the system.

Following these guidelines ensures safe operation, optimal performance, and long-term reliability of your battery bank.

Best Practice guide for Paralleling 12V Lithium Batteries 

Battery Compatibility
Same Chemistry & Voltage: All batteries must be of the same type (e.g., Life PO₄) and nominal voltage (e.g., 12.8V).

Reasons:
Same Chemistry & Voltage: Different chemistries (e.g., LiFePO₄ vs. NMC) have different charging profiles and voltage ranges. Mixing them can cause improper charging, damage, or safety hazards

Same Capacity & Age
Batteries must be of the same capacity to ensure balanced charging/discharging. Ideally of a similar age.
Reasons:
Same Capacity & Age: Batteries with different capacities or ages will charge and discharge unevenly. Older or smaller batteries may become overstressed, reducing lifespan or causing failure.

State of Charge (SOC) Matching
Batteries should be at the same voltage level before connecting in parallel. Mismatched voltages can cause large inrush currents, potentially damaging the batteries or wiring. The Optimal method to achieve this is to charge each battery separately to full capacity with the same charger prior to parallel connection.
Reasons:
If batteries have different voltages when connected, the higher-voltage battery will rapidly discharge into the lower-voltage one. This creates large inrush currents that can damage cells, wiring, or connectors.

Battery Management System (BMS)
Each battery should have a built-in BMS to manage charging, discharging, and cell balancing.
If using an external BMS or a centralized system, ensure it supports parallel configurations.
Reasons:
A BMS ensures safe operation by preventing overcharge, over-discharge, and balancing cells. Without proper BMS coordination, parallel setups can lead to uncontrolled current flow and cell imbalance.

Current Sharing
Please note that differences in internal resistance can cause uneven current distribution, leading to overloading one battery
Use matched cables (same length and gauge) for each battery to help balance current flow.
Reasons:
Internal resistance differences cause uneven current distribution. One battery may supply more current, overheating and degrading faster. Matching cable length and gauge helps equalize resistance and balance load.

Fusing and Protection
Install a fuse or circuit breaker on the battery's main positive output to protect against short circuits or other faults.
Reasons:
They protect against short circuits and isolate faults, reducing fire and damage risk.

Charging Considerations
Use a charger compatible with lithium batteries and capable of handling the total combined capacity. (ie 2x 200AH batteries combined for a 400AH Bank)
Ensure the charger does not exceed the voltage or current limits of the batteries or BMS.
Reasons:
Overvoltage or excessive current for prolonged periods can cause damage to batteries internal BMS or cells leading to shorter life span. Proper charger selection ensures safe and efficient charging.

Monitoring
Use a battery monitor or the internal Bluetooth to track voltage, current, and SOC across the entire bank.
Reasons:
Continuous monitoring of voltage, current, and SOC ensures early detection of any faults.