Installing the SERVTEC CAN-Bus Bridge with a Sunsynk 8k ECO Inverter
A Practical Case Study for one of our customers.
Home battery systems based on Pylontech US-series modules have become extremely popular thanks to their reliability and long cycle life. However, many users want more control over the maximum charge voltage, allowing them to run their LiFePO₄ batteries at slightly reduced top-of-charge to promote long-term health and lower cell stress.
This case study looks at how one of our customers, Jack Francis integrated the SERVTEC CAN-Bus Bridge into his Sunsynk 8k ECO inverter system to achieve exactly that. The installation follows the guidance from the official SERVTEC manual and demonstrates how simple the upgrade can be.
Why Use a CAN-Bus Bridge?
Pylontech batteries communicate with hybrid inverters over CAN-bus, providing information such as SOC, charge/discharge limits, temperature, and alarms. One of the values also transmitted is the recommended maximum charge voltage, typically around 53.2 V for a 48 V Pylontech stack.
The SERVTEC CAN-Bus Bridge sits transparently between the inverter and the battery, passing all original messages but substituting a lower Charge Voltage Limit (CVL). This enables users to cap the inverter’s charge voltage — for example at 51.8 V — without disabling CAN communications or switching to “user-defined” modes.
This approach keeps:
- SOC reporting accurate
- All protections active
- Charge/discharge limits dynamic
- Alarms still delivered correctly
while simply adjusting the top-charge behaviour.
System Components
The installation in this case involved:
- Sunsynk 8k ECO hybrid inverter
- Pylontech 3 x US5000 and 5 x US3000 battery modules
- SERVTEC CAN-Bus Bridge
- 1A USB 5V Charger
Installation Overview
The following summarises the installation process performed on Jack’s system.
1. Full Shutdown
All DC inputs, PV strings, the battery stack, and AC sources were powered down.
2. Battery-Side CAN Connection
The existing CAN cable between the Pylontech master battery and the inverter was removed from the inverter and connected into the battery-side CAN port on the SERVTEC Bridge.
3. Inverter-Side CAN Connection
The Bridge was connected to the Sunsynk 8k ECO’s BMS/CAN port.
4. Supplying Power to the Bridge
A Standard USB 5V charger was used to power the bridge,
5. Power-Up Sequence
The system was re-energised in the following order:
-
Battery bank
-
CAN-Bus Bridge
-
Sunsynk inverter
This ensures the inverter sees the modified CAN data as soon as it boots.
6. Configuring the Charge Voltage Limit
The Bridge broadcasts a temporary Wi-Fi network for setup. Through the browser-based interface, the adjustable CVL was set to 51.8 V, a common value used to limit cycling stress on LiFePO₄ cells.
The setting was saved, and the device immediately began injecting the adjusted voltage limit into the CAN stream.
7. Verification
On boot, the Sunsynk 8k ECO’s battery page showed the new maximum charge voltage being applied. SOC reporting, battery capacity, charge/discharge current limits, and alarms remained fully functional.
Benefits Observed
While the CAN-Bus Bridge is a small inline device, it delivers several notable advantages for users focused on long-term battery life:
✔ Reduced Cell Stress
By avoiding frequent charging to 100%, the battery operates in a more stable voltage region, reducing heating and mechanical expansion cycles.
✔ Improved Cycle Longevity
Lower CVL settings can significantly extend the usable lifespan of LiFePO₄ modules.
✔ No Need to Switch to “User Battery Mode”
All normal CAN communications remain active, unlike many alternative methods that require losing BMS integration.
✔ Completely Reversible
The system can be returned to factory configuration by simply restoring the original CAN cable.
Conclusion
The install demonstrated here shows how straightforward and effective the SERVTEC CAN-Bus Bridge can be when paired with a Sunsynk inverter and Pylontech battery stack.
For users who want to reduce cycling stress and optimise long-term battery health, this solution — when installed correctly and with full awareness of its limitations — provides a practical upgrade path.
Purchase your CAN-Bus bridge here: