· SH Energy editorial
When a lithium battery talks to an inverter, the physical link is only the beginning. The two devices have to agree on the messages they exchange, how limits are expressed, and what happens when the battery wants to stop the charge. Collect that evidence in writing before the commissioning visit rather than discovering the gap on site.
1. BMS-CAN is a bus, not an agreement
Public manufacturer documentation is explicit that a shared bus does not by itself create compatibility. Victron Energy's battery compatibility guidance states that, for lithium and other chemistries, it publishes documentation and guidelines for the case where communication is required between the power electronics and the battery management hardware, and that these are mostly connected via "BMS-Can" on a GX device.
The same page maintains a list of batteries known to have been tested, and notes that many further third-party batteries are also compatible and permitted under warranty, but that these "will require additional information and support from a local supplier". That sentence is the whole problem in one line: the cable fits, the messages may not.
2. The evidence pack to request in writing
Ask for the following before accepting a compatibility claim, and keep the answers attached to the project file. Vague assurances are not substitutions for any item on this list.
- Protocol identity: which protocol the battery exposes for this exact model and firmware version, and on which interface.
- Physical layer detail: pinout, baud rate and whether the port is a dedicated BMS port or shared with another function.
- Message or register list: the telemetry and command set the device sends and accepts for this configuration.
- Confirmed pairings: a written list of inverter models that have actually been tested with this battery, with firmware versions where available.
- Behaviour at the end of charge: how the device signals that the battery is full.
- Failure behaviour: what the battery does when it wants to stop charge or discharge, and whether it uses a hardware disconnect.
- Version control: a named contact and a revision reference, so a later firmware change is traceable.
One practical warning: manufacturers do not always publish this material openly. Victron states that it provides its battery protocol specification to battery manufacturers on request from a regional manager — an exchange between manufacturers. If a supplier cannot produce a register or message list at all, that is itself the answer, and the communication claim should be treated as unproven rather than assumed.
3. The limit-handling detail that causes most commissioning alarms
Victron documents a recurring pattern worth reading before any site visit. Its guidance explains that, as a battery becomes fully charged, Victron requires the battery management system to change the Charge Voltage Limit (CVL) to restrict the power flowing to the battery. If the system instead tries to restrict power using the Charge Current Limit without adjusting the Charge Voltage Limit, Victron reports that this can trigger Overcharge, Overvoltage or Overcurrent warnings.
The same page describes confusing cases where a battery management system blocks charge or discharge current, or sets the charge current limit to zero when full, producing inverter warnings that look like an overload on a lightly loaded system — leading to extensive troubleshooting and a perfectly healthy inverter on the test bench, with the true cause being the battery's own control behaviour. Every hour of that diagnosis is avoided by confirming limit handling in advance.
4. Safety overrides belong in hardware
Communication is a control layer, not a protection strategy. Victron's safety warning on the same page states plainly that a battery must be intrinsically safe and must include its own large disconnect mechanism, such as a contactor, and that relying only on digital signals telling the inverter or charger to stop charging is not sufficient.
When you review a proposed pairing, check what physically disconnects the battery if the bus fails, if a message is missed, or if the controller hangs. A design that depends entirely on a digital stop command has a single point of failure on the communication link.
5. Keep the sourcing boundary honest
Communication evidence sits in the middle of a sourcing decision, which makes it easy to blur. A supplier can help you obtain the model-level documents, coordinate with the China-side manufacturer and tell you which pairings have already been tested. A supplier cannot declare a pairing compatible on behalf of the inverter manufacturer, and should not present a potential sale as though it were already an approved integration.
If a pairing is new, say so, price the engineering honestly, and agree in advance how the first commissioning will be supported. That is a more durable commercial position than a compatibility claim that fails at the point of energisation.
Copy-ready enquiry to the battery and inverter suppliers
Frequently asked questions
Is a CAN cable enough to make a battery and inverter work together?
No. Victron's published battery compatibility documentation describes lithium batteries as mostly connected over BMS-Can on a GX device, and publishes a list of batteries known to have been tested. A physically correct cable proves the wiring, not that the two devices agree on the messages they exchange.
Why does a battery register map sometimes arrive blank or incomplete?
Victron states that it provides its battery protocol specification to battery manufacturers on request from a regional manager. In other words, protocol documentation is exchanged between manufacturers rather than published as an open installer document. If a supplier cannot provide a register or message list, treat the communication claim as unproven.
What causes overcharge or overvoltage warnings at the end of a charge cycle?
Victron describes a common problem where the battery management system restricts power using the Charge Current Limit without adjusting the Charge Voltage Limit. In that situation Victron reports that Overcharge, Overvoltage or Overcurrent warnings can appear. The remedy is protocol behaviour, not a bigger cable.
Is a digital stop-charge command enough for safety?
Victron's safety warning states that a battery must be intrinsically safe and include its own large disconnect mechanism such as a contactor, and that relying only on digital signals telling the inverter or charger to stop charging is not sufficient.
Discuss a documentation or sourcing enquiry
Send the exact battery and inverter models, their firmware versions, and whatever protocol documentation you already hold to jimmy@sunhongenergy.com, or contact Jimmy on WhatsApp. For the surrounding work, see the battery and inverter compatibility checklist, the inverter selection flowchart and our quality and documents page. Compatibility, warranty treatment and commissioning outcomes are decided by the battery and inverter manufacturers for the exact configuration, not by SH Energy.
Sources and scope
Reviewed 22 October 2026. Primary source: Victron Energy's public battery compatibility documentation at victronenergy.com/live/battery_compatibility:start, page last modified 23 September 2026 and retrieved 16 October 2026. The statements attributed to that page are: that lithium and other chemistries connect mostly via BMS-Can on a GX device; that it maintains a list of batteries known to have been tested; that additional third-party batteries are permitted under warranty but require information and support from a local supplier; that Victron provides its battery protocol specification to manufacturers on request from a regional manager; the CVL/CCL limit-handling behaviour and the resulting warnings; the described diagnostic pattern when a BMS blocks current or sets the current limit to zero; and the safety warning that a battery must include its own large disconnect mechanism. Victron Energy is referenced as a documentation example only; SH Energy is not affiliated with, authorized by or a service partner of Victron Energy, and this article does not claim that any SH Energy product has been tested with any specific inverter. The checklist and template are SH Energy editorial recommendations. Confirm protocol behaviour and safety design with the responsible manufacturers for your exact configuration. Search demand for this topic has not been quantified.