> ## Documentation Index
> Fetch the complete documentation index at: https://learning.kent.co.in/llms.txt
> Use this file to discover all available pages before exploring further.

# Comm Fault: Battery, Meter, and Parallel Link Failures

> Battery BMS, meter RS485, and parallel bus communication failures — the cable-first triage flow and post-repair SOC verification for Kent hybrid sites.

Your goal is to identify which communication link has failed and restore it. Work one link at a time: the alarm string names the link — trust it.

**Symptom:** a comm alarm on the display, missing or frozen SOC, grid data not updating, or parallel units that have stopped sharing load.

## Check first

1. **Which link has failed?** Battery (SOC / BMS), meter (grid data), or parallel bus — the alarm string names it. Fix one link at a time and re-test before moving to the next.
2. **Kent battery link down? Crossover cable first.** A straight RJ45 patch cable between the Kent battery and the inverter is a guaranteed comm failure. Verify the labelled Kent F1 crossover cable is in place before any settings work.
3. **Connectors fully seated at both ends, in the correct port?** Click the RJ45s home at both ends and confirm you are in the port the platform page names — before deeper diagnosis.

## Causes

| Link                            | How it shows                                                                       | Fix                                                                                                                                                                                                                                                        |
| ------------------------------- | ---------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Battery — cable fault           | Kent G3: **CAN Fail** · Kent M1: **E400–E402**; SOC missing or 0%                  | [Cable Checks](/battery/cable-checks): verify the label, check continuity against the pin card, reseat both ends; re-terminate if needed                                                                                                                   |
| Battery — wrong selection       | Kent G3: **BatName-FAIL** · wrong model name on display                            | Select the Pylon-family entry per the platform commissioning page — only after the cable is proven                                                                                                                                                         |
| Battery — pack absent or asleep | Kent G3: **No-Battery**; pack LED dark                                             | Check breaker and switch states; wake per [Battery Not Charging](/troubleshooting/battery-not-charging); note that the "No Battery" menu option exists only to suppress the alarm when a battery is genuinely not installed — it does not fix a comm fault |
| Meter — RS485 link              | Kent G3: **MET-SLT-Fail** / meter-fault class; grid data frozen                    | Check A/B polarity per the platform pin map, meter type selection, and that the meter has a live supply — follow [Meter & Phase Matching](/ct-meter/meter-phase-matching)                                                                                  |
| Parallel bus                    | Kent M1: **E606** (parallel machine abnormal) · shared power erratic between units | Parallel cabling, DIP switch positions, and unit addresses per the platform page — DIP schemes differ between M1 and G3, see the [Mixed-Fleet Cheat Card](/mixed-fleet/cheat-card)                                                                         |
| Multi-pack bank internal        | One pack's data missing; aggregated SOC figures look wrong                         | Check pack addresses against the address map on the commissioning sheet; the master pack carries the full bank data                                                                                                                                        |

<Note>
  **Datalogger stick "offline" is not a display comm fault.** The datalogger is fitted physically per the installation pages and is activated with Kent Central Command — documentation to follow. Nothing in commissioning or troubleshooting depends on datalogger connectivity.
</Note>

<Note>
  After restoring a battery comm link, close out with the **full-charge SOC verification** from [SOC Mismatch](/battery/soc-mismatch). Drift accumulated while the BMS link was down does not self-correct.
</Note>

## Escalate when

* BMS stays silent after the cable is verified against the pin card and the battery selection is confirmed correct — this is a battery-level case for Kent service.
* A meter is confirmed dead with wiring, type selection, and supply all verified — replacement case.
* Parallel sync fails on a verified cabling, DIP, and address setup.

<Note>
  **Escalate to Kent New Energy service only** — through your registered Kent partner channel or the Kent service desk details on your work order. Do not contact any third-party or component-manufacturer support line for a Kent-branded system: tickets outside the Kent channel are not tracked, not covered, and can void warranty handling.
</Note>

## Related pages

* [Cable Checks](/battery/cable-checks)
* [BMS Comms Basics](/battery/bms-comms-basics)
* [Meter & Phase Matching](/ct-meter/meter-phase-matching)
* [Battery Not Charging](/troubleshooting/battery-not-charging)
* [When to Escalate](/troubleshooting/when-to-escalate)