SMA Storage M BMS Unit STM-BMS-10
SMA STM-BMS-10: the Battery Management System unit of the SMA Storage M high-voltage storage system. You need one per tower: without the BMS, STM-BM-4.09-10 modules cannot be connected to the inverter.
It manages 3 to 12 modules (12.3-49.1 kWh usable), talks to the Sunny Tripower Hybrid X over CAN, and integrates the input-side disconnection point and reverse-polarity protection. IP66, 530 x 140 x 405 mm, 11.3 kg.
The SMA STM-BMS-10 is the battery management unit that turns a stack of SMA Storage M modules into a working storage system. It monitors the STM-BM-4.09-10 modules in the tower, manages charging and discharging, communicates with the hybrid inverter and provides the DC connection to the Sunny Tripower Hybrid X or Sunny Boy Smart Energy.
One per tower, always: the line missing from many orders
The BMS is neither an optional accessory nor part of the inverter: every Storage M configuration, from 3 to 12 modules, consists of one STM-BMS-10 unit plus the modules. Ordering only modules in the belief that battery management is built into the inverter leaves you with a storage system that will not start. Always budget for this item, one per battery tower.
It is also a future-proof choice: the same unit handles a 3-module tower today and a 12-module tower tomorrow, so a system that starts at 12.3 kWh can grow without replacing it, within the capacity allowed by the inverter (36.8 kWh on Hybrid X 5-15, 49.1 kWh on Hybrid X 20-30).
STM-BMS-10 technical specifications
| Function | Battery Management System for SMA Storage M |
| Modules managed | 3 to 12 STM-BM-4.09-10 modules per tower |
| Tower usable capacity | 12.28 kWh to 49.12 kWh |
| Tower operating voltage | From 151.2-191.7 V (3 modules) to 604-766.8 V (12 modules) |
| Charge and discharge current | 50 A with Sunny Tripower Hybrid X; 30 A with Sunny Boy Smart Energy (up to 28.7 kWh) |
| Protection | Input-side disconnection point, DC reverse-polarity protection |
| Overvoltage category | II on battery and inverter side |
| Connections | DC MC4 Evo 2; CAN communication via RJ45, SMA battery interface |
| Degree of protection | IP66, indoor and outdoor installation |
| Operating temperature | -20 °C to +50 °C, optimum 15-30 °C |
| Maximum altitude | 3,000 m |
| System certifications | CE, UN 38.3, IEC 62619, IEC 62477, VDE 2510-50 |
| Dimensions (W x H x D) | 530 x 140 x 405 mm |
| Weight | 11.3 kg |
| Warranty | 2 years standard, 10 years with registration within 30 days of commissioning |
Footprint of the complete tower
The tower always has the same footprint, 530 x 405 mm, and only grows in height: 605.5 mm and 120 kg with 3 modules, 871.5 mm and 191.6 kg with 5, 1,270.5 mm and 299 kg with 8, 1,802.5 mm and 442.2 kg with 12. These are concrete-floor loads: on light floors or mezzanines a tall tower must be checked before purchase, and handling the 36 kg modules takes two people.
Frequently asked questions
Is the BMS included with the modules or the inverter?
No. It is a separate component, ordered together with the modules: one STM-BMS-10 unit per Storage M tower. Sunny Tripower Hybrid X inverters communicate with the BMS but do not replace it.
Can I start with a few modules and add more later?
The same unit manages 3 to 12 modules, so the tower can grow without changing the BMS, up to the maximum allowed by the inverter. Plan the extension, though: adding new modules next to aged ones makes the system behave like its weakest module.
Does it work with SMA Home Storage batteries?
No. The STM-BMS-10 only manages Storage M STM-BM-4.09-10 modules. Home Storage uses 3.28 kWh modules and its own components, and the two systems cannot be mixed.
Which inverter do I need?
The system is designed for the Sunny Tripower Hybrid X, where it runs at 50 A, and is also compatible with the single-phase Sunny Boy Smart Energy, where current drops to 30 A and maximum capacity is 28.7 kWh. Compatibility with other brands' inverters is not provided by the manufacturer.
How much space does it need in a garage?
A footprint of 530 x 405 mm plus the front access space and clearances given in the installation manual. Height ranges from about 60 cm with 3 modules to 1.8 m with 12: a medium 6-module tower is around one metre tall.
