Quick Answer

When several LiFePO4 battery packs operate in parallel, the current shown for each pack may not always be identical.

If four packs supply 120A in total, 120A ÷ 4 = 30A per pack. 30A is useful as a reference average, but it does not mean every pack must always measure exactly 30A.

Instead of judging one reading, check whether the same pack repeatedly carries more or less current under comparable operating conditions.

Diagnostic path: Current → Voltage → SOC → BMS Status → Connection Path

The goal is to determine whether you are seeing temporary operating variation or a repeatable pack-level difference that needs further investigation.

1. First, Compare the Packs Under the Same Condition

Do not diagnose unequal pack current from a single screenshot. Compare the packs at the same time, under the same charge or discharge condition, with a comparable system load, and using the same monitoring method. Then repeat the observation.

Key question: Does the same pack repeatedly show different current from the others?

A one-time difference provides much less information than a repeatable pattern.

2. Do Not Treat Total Current ÷ Pack Count as a Pass/Fail Limit

Suppose four parallel packs supply 120A. The reference average is 120A ÷ 4 = 30A per pack.

This helps you compare the four packs, but it does not mean every pack must always show exactly 30A, or that a pack above or below 30A is automatically faulty.

There is no universal percentage difference that should automatically be treated as acceptable or unacceptable for every parallel battery system.

Total Current ÷ Number of Packs = Reference Average, not a universal acceptance limit.

3. If the Difference Repeats, Compare More Than Current

If the same pack repeatedly carries more or less current, do not diagnose the problem from current alone.

Check	What You Are Looking For
Current	Is the same pack repeatedly the outlier?
Voltage	Does that pack also show a different voltage pattern?
SOC	Does its SOC also behave differently over repeated observations?
BMS Status	Is it in a different charge, discharge or protection state?

SOC is useful here as a supporting signal. A different SOC reading does not by itself prove why the current is different.

4. Then Check the Pack and Its Connection Path

If other pack data is also different

Compare the affected pack's voltage, SOC, temperature where available, BMS operating status, and repeated current behavior. The purpose is to determine whether the current difference is part of a wider pack-level pattern.

Different current is an observation, not yet a diagnosis.

If the pack data looks similar but its current remains different

Check the complete parallel connection path. Compare cables, connectors, terminals, busbar connections, and connection condition.

Useful question: Does this pack have a comparable electrical path to the common connection point?

5. Decide: Monitor or Investigate?

What You See	What to Do
Current differs temporarily, while other pack data remains reasonably consistent	Monitor under comparable conditions
The same pack repeatedly carries more or less current	Compare voltage, SOC and BMS status
The current outlier also shows repeated voltage, SOC or status differences	Investigate the affected pack
Pack data looks comparable but one branch remains a current outlier	Check the parallel connection path
One pack repeatedly enters a different charge/discharge or protection state	Investigate the pack/BMS operating condition
The available data still cannot explain the pattern	Request project-specific verification

6. How DALY Multi-Pack Monitoring Helps

For supported DALY 4th Gen Home Energy Storage BMS multi-pack configurations, individual pack information can be viewed for comparison, including Pack Number, State, Voltage, Current, SOC, CHG-MOS and DSG-MOS. Supported configurations can include up to 16 battery packs.

You can compare individual packs and identify which pack repeatedly behaves differently.

This monitoring capability should not be interpreted as a guarantee that every parallel pack will always carry exactly the same current.

7. What Should You Send DALY for Verification?

If the same pack repeatedly shows different current and the available data does not explain why, prepare: battery chemistry and S count, Ah per pack, number of packs, exact BMS model, synchronized current/voltage/SOC/status data, cable and busbar arrangement, inverter brand/model, operating condition, and whether the same pack repeatedly becomes the outlier.

FAQ

Should parallel LiFePO4 battery packs always show exactly the same current?

No. Total current divided by the number of packs is useful as a reference average, not as a universal pass/fail requirement. Check whether the same pack repeatedly behaves differently under comparable operating conditions.

Can cables and connections affect current sharing between parallel packs?

They can influence current distribution. If one branch repeatedly shows different current, compare its cables, connectors, terminals and busbar connections with the other branches.

Does different pack current mean the BMS is faulty?

Not necessarily. Different current is an observation, not a diagnosis. Compare repeated current behavior with pack voltage, SOC, BMS status and the parallel connection path before identifying a cause.