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A Kent lithium installation without a live BMS communication link is running blind — the inverter is estimating charge state from voltage alone instead of reading it from the battery. This page explains what closed-loop means, how to confirm it on the display, and the pin facts you need to get the cable right.

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Closed loop is mandatory for lithium

There are two modes an inverter can use to manage a battery:
ModeHow it worksWhen to use
Closed loopInverter reads live SOC, limits, and temperature from the BMS over the comm cableRequired for all Kent Lithium Battery installations
Open loopInverter estimates everything from DC voltage aloneLead-acid banks only — not for lithium
On a closed-loop Kent lithium system, the inverter display must show the battery model name and a live SOC percentage that updates. If the SOC is missing, frozen, or reads 0 % while the voltage looks normal, the comm link is down — go to Cable Checks before touching a single setting.
  • CAN is the lithium link on both Kent platforms. The Kent Lithium Battery communicates over CAN to the inverter’s BMS port.
  • RS485 is the alternative battery interface on the same RJ45 port. It exists for battery types that use it — it is not the Kent Lithium Battery’s protocol.
  • Lead-acid banks use no data link at all. The inverter manages them by voltage, with a PT1000 temperature sensor on the Kent M1.

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The pin facts

Both Kent inverters define their BMS RJ45 port identically (EIA/TIA 568B):
RJ45 pinKent G3 & M1 inverter BMS portSignal
Pin 4CAN-HCAN high
Pin 5CAN-LCAN low
Pin 6ARS485 A (alternative)
Pin 3BRS485 B (alternative)
The Kent battery’s RJ45 is the mirror image — CAN-L on pin 4, CAN-H on pin 5. That is exactly why the labelled Kent crossover comm cable exists. The full pin card, the continuity check, and the field fallback for re-terminating a cable on site are all on Cable Checks.
Both Kent source manuals carry the same instruction when pin definitions differ between ends: check both ends before connecting, and if they differ, cut the RJ45 at one end and re-terminate to match. On a Kent lithium pairing that check always leads to the same conclusion — use the labelled Kent crossover cable.

Kent G3

The CAN cable enters through COM1 or COM2 and connects to the BMS RJ45 on the comm interface board. Routing and cable gland placement follow the Kent G3 Battery Wiring guide.

Kent M1

The BMS RJ45 sits on the comm interface panel. Routing follows the Kent M1 Comms & Datalogger guide.
Multi-pack banks: packs parallel among themselves. Only one master pack’s CAN port connects to the inverter — one cable for the whole bank, no matter how many packs it contains.

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Common mistakes

  • Chasing menu settings for a comm fault that is actually the cable. Check the cable first, always.
  • Reading “battery voltage visible on screen” as “comms are fine” — voltage is analog; comms is the live SOC reading.
  • Plugging the battery link into the wrong RJ45 on a multi-port comm strip. Label your cables and trace before you connect.
  • Accepting a one-time SOC reading as confirmation of a handshake — the SOC must update continuously.