The inverter says one SOC, the battery indicates another — or the number is stuck. Here is
why that happens and the Kent way to bring the two back together.
Check first
- Is the link closed-loop right now? The SOC on the display must be updating. A
frozen or missing SOC is a comm problem, not a calibration problem — go to
Cable Checks.
- Was there a recent comm fix, firmware event or long low-power spell? All three are
classic triggers for drift.
- Is the mismatch stable or growing? Note both readings and the time — Kent service
will ask.
Why SOC drifts
- Comms fell back to voltage estimation. With the BMS link down, the inverter estimates
from DC voltage — on lithium chemistry that estimate wanders badly in the flat middle of
the curve. Restore comms first; the mismatch itself is then just history.
- Long spells at low power. The source manual for the Kent G3 states it directly: when a
lithium battery stays at low power for a long time, the SOC measurement loses accuracy and
the pack needs a charge to 100 % to restore it.
Recalibrating — Kent G3
The Kent G3 has an official tool for exactly this: the Battery Healing switch
(professional Function Settings). With it ON, the system charges the pack up from low SOC —
grid assists from Force-charge SOC to Overdischarge SOC, then PV takes priority up to the set
Battery Healing SOC — and the battery does not discharge until that target is reached,
re-anchoring the SOC measurement.
Professional-menu access is partner-gated — see
Authorized-Only Actions.
Recalibrating — Kent M1
Pending Kent validation. [KNB-VAL-22]
The Kent M1 SOC-recalibration procedure is under confirmation with the Kent battery team.
Until published here: after restoring comms, bring the bank to 100 % through normal
operation (a charge window or high-PV day), verify the inverter SOC then tracks the
battery’s own indication, and record both readings. Do not force-cycle the bank to empty as
a “calibration”, and treat a mismatch that survives a full charge as an escalation.
After any BMS comm repair
Whatever platform: once the link is back, run the bank through a full charge and verify
the two SOC readings agree before closing the ticket — drift accumulated while the link
was down does not clear itself. Record the post-repair readings on the service sheet.
Common mistakes
- “Calibrating” by settings changes while the real fault is the comm cable.
- Reading the flat lithium voltage curve as proof the SOC number must be right.
- Closing a comm-repair ticket without the post-repair full-charge verification.
- Letting a backup-heavy site live permanently at low SOC and wondering why the gauge lies —
see Not Charging / Not Discharging for the settings
that prevent it.
When to escalate
Escalate when the mismatch survives a verified-good cable and a full charge — that is a
BMS-level case for Kent battery service, with your recorded readings attached.
Related pages
