Short answer: no, and this is the single most expensive misunderstanding in DIY off-grid solar.
CAN bus is a physical and signalling standard. It defines voltage levels, wiring, termination, and how bits get on the wire without collisions. It says nothing about what the messages mean.
Closed-loop operation needs a second agreement on top of that: both units using the same message format, the same identifiers for state of charge and charge current limit and cell temperature, and the same behaviour when a limit is hit. Two devices can both speak CAN perfectly and understand nothing the other says, exactly like two people reading aloud fluently from books in different languages.
Why this matters more than it sounds
Without closed loop, a lithium pack runs on voltage cutoffs alone. The inverter guesses state of charge from terminal voltage, which on a LiFePO4 curve is nearly flat across the middle of the range and therefore close to useless. Charging tapers at the wrong time. The BMS protects the cells by disconnecting rather than by asking the inverter to back off, and a hard BMS disconnect under load is not a graceful event.
People buy a comms-capable battery specifically to avoid that, wire it to an inverter that speaks CAN, and reasonably assume the safety layer they paid for is active. Sometimes it is not.
How to actually check
There is one reliable test and it is documentary rather than electrical. Find a manufacturer document, from either side, that names the other unit by model. Battery makers usually publish this as a supported inverter list. Inverter makers usually publish it as a protocol selection table, where you choose your battery brand in a settings menu.
If a document names your exact pairing, you have closed loop and you know which protocol setting to select. If no document names it, the honest status is unverified, no matter how confident a forum reply sounds. Protocol implementations get revised, and a pairing that worked for someone in 2023 can fail after a firmware update on either side.
The awkward part
Most pairings have no such document. Manufacturers test against the equipment they expect to be sold alongside, and the DIY market mixes brands far more freely than any manufacturer plans for. That gap is real, it is not a documentation oversight that will be tidied up, and pretending it does not exist is how people end up with an unprotected pack.
Two things follow. If the safety layer matters to you, buy a pairing that is documented, and treat the protocol setting as part of the purchase decision rather than a detail to sort out during installation. If you already own an undocumented pairing, set conservative voltage limits manually and do not assume the BMS will negotiate on your behalf.
Status: general explanation of the CAN standard and closed-loop requirements. No single manufacturer document is cited because this describes how the layers relate rather than any one product’s figures. Component-specific protocol support is tracked on the component pages, where each claim carries its own source.