Sigenergy issued a product release notice dated 18 August 2026 introducing the SigenStack DC Combiner Box, model SigenStack BC CMB-4. The same notice records a change to the product codes of the SigenStack Battery Controllers, and the two changes are linked: the combiner box does not work with the controller models currently in the field.
In a standard SigenStack installation each SigenStack Battery Controller connects directly to a hybrid inverter, which fixes the system at a single controller-to-inverter pair. The manufacturer states that applications needing longer backup duration or more storage capacity require multiple SigenStack systems to be aggregated onto one inverter. The combiner box is the component that does this, combining the DC outputs of up to four battery controllers and presenting them to a single hybrid inverter.
The notice records the following.
| Product code | Product model | Dimensions (W / D / H) | Weight | Available |
|---|---|---|---|---|
| 11112000 | SigenStack BC CMB-4 | 730 / 217.5 / 650mm | 35kg | 30 September 2026 |
Sigenergy states that these dimensions and the weight are those of the product itself. The published ratings are a maximum operating current of 180A on the battery controller side across a maximum of four controller connections, a maximum operating current of 180A on the inverter side across a single inverter connection, and a system ingress protection rating of IP55. Each battery controller connects on a BAT+/BAT- DC cable interface, the inverter connects on its own BAT+/BAT- interface, and communication runs over an RJ45 network interface.
The compatibility constraint is the part that carries a cost
The combiner box is compatible only with the new battery controller models, product codes 11142000 and 11142001. Sigenergy states plainly that the existing battery controller models are not compatible with it, and that the corresponding new models must be selected when ordering a combiner box.
The distinguishing mark is the -BST suffix in the model name. The two compatible controllers are the SigenStack BC M2-0.5C-BST and the SigenStack BC M2-1C-BST. A controller without that suffix cannot be connected to the CMB-4.
The controllers transition to new codes on the following basis.
| Previous product code | Product model | New product code |
|---|---|---|
| 11140003 | SigenStack BC M2-0.5C-BST | 11142000 |
| 11140002 | SigenStack BC M2-1C-BST | 11142001 |
The notice states that battery controller models transition to the new product codes from 30 September 2026, the same date the combiner box becomes available.
This matters at the point of ordering rather than the point of installation. A commercial or industrial site specified now, with a single battery controller and an expectation of adding storage later, reaches the expansion stage with hardware that cannot be combined. The constraint attaches to the controller that was ordered, not to the combiner box that is added afterwards, so it is decided months before anyone notices it.
Mixed capacities are permitted across the connected systems
Sigenergy records one point of flexibility worth noting alongside the constraint. Where multiple SigenStack systems are connected to a single CMB-4, the individual systems may hold different battery capacities. The capacity of each connected system does not need to be identical.
For a site expanding in stages over several years, that removes the requirement to match a later addition to the size of the original installation.
The installation guide has not been published
Sigenergy states that the installation guide for the SigenStack BC CMB-4 is expected to be available in early September 2026, and that customers will be notified when it is. The manufacturer directs questions on installation or configuration of the CMB-4 to its sales and service contacts.
The applicable documents remain the controlling reference
This article is a dated record of a manufacturer notice. It is not an installation instruction and does not replace the current product documentation.
Installers and specifiers should confirm the exact product code, the current manual for the specific equipment on site, and any subsequent manufacturer notice before ordering or commencing work. Sigenergy states in the notice that the information reflects the current state of technology and is subject to change without notice, and that it excludes all representations and warranties relating to the file and its contents. Current package documents, manufacturer instructions, licensing requirements and controlled work procedures apply to the specific task, and any conflict should be resolved before the equipment is installed or returned to service.
