The VCC 1212-50 CI B2B charging converter from Votronic (MPN: 3361) charges the onboard or service battery in a controlled manner while driving, using the starter battery and alternator. The device is designed for 12-V onboard electrical systems, provides up to 50 A of charging current, and supports lead-acid, gel, AGM, and LiFePO4 batteries. With nine selectable charging programs, adjustable current draw, temperature monitoring, and a CI bus interface, the charge converter is particularly well-suited for motorhomes, specialty vehicles, boats, and similar mobile applications.
Controlled 50-A battery charging while driving
12 V to 12 V B2B charging converter with a maximum charging current of 50 A
9 charging programs for lead-acid, gel, AGM, and LiFePO4 batteries
Adjustable charging current limit to 39 A or a maximum of 50 A
Input voltage range from 10.5 to 16.5 V, also designed for modern alternator systems
Three additional limit levels for maximum current draw: 49 A, 42 A, or 33 A instead of a maximum of 68 A
Automatic activation via D+, ignition, or voltage-controlled
Lead-acid temperature compensation and protection functions for LiFePO4 batteries
CI-Bus connection as well as connections for remote display and sensor wires
Trickle charging of the starter battery at 0 to 3 A
Temperature sensor 825 included in the scope of delivery
Version without galvanic isolation
Regulated charging independent of the alternator
The converter is installed between the starter battery and the service battery and ensures that the service battery is supplied with a defined charging voltage and a controlled charging current while driving. As a result, the service battery is not simply connected directly to the starter battery or alternator, but is charged according to the selected battery characteristic curve. This is particularly relevant for vehicles equipped with modern, voltage-regulated alternators. The charging converter can also compensate for significant voltage fluctuations from the alternator, thereby enabling a complete and controlled charge of the service battery. The automatic power control takes into account, among other things, the load on the starter battery and the alternator.
Charging Programs for Lead-Acid and LiFePO4 Batteries
A total of nine charging programs are available via the device settings. For lead-acid batteries, charging curves are provided for lead-acid, gel, and two AGM variants. In addition, there are five programs for LiFePO4 batteries with different charging voltages or requirements, including variants for heated batteries. For lead-acid batteries, the included temperature sensor can be used to adjust the charging voltage based on temperature. For LiFePO4 systems, temperature monitoring also serves to protect against critical battery temperatures. LiFePO4 batteries must have their own BMS and the necessary safety features.
Adjustable Load on the Alternator and Starter Circuit
Not every vehicle installation is designed for the charging converter’s maximum input current. Therefore, it can be set to different input current limits. In addition to the maximum value of 68 A, limits of 49 A, 42 A, and 33 A are available. The output charging current can also be limited. Instead of the maximum 50 A, a limit of 39 A can be set. This allows for adaptation to the existing installation and the connected onboard battery.
Automatic Activation and Modern Vehicle Electrical Systems
Several control options are available for activating the unit. Depending on the vehicle, activation can be triggered via a D+ signal, the ignition, or voltage control. This allows it to be integrated into both traditional and modern vehicle electrical systems. The documentation explicitly states that the unit is suitable for vehicles with Euro 6 alternators or their voltage-regulated operation. The input voltage range is 10.5 to 16.5 V.
Connections, Monitoring, and CI-Bus
In addition to the power connections, the unit features connections for sensor and control functions. Separate sensor leads can measure the voltage directly at the starter battery and the service battery. This allows voltage drops in the wiring to be accounted for during regulation. A CI-Bus interface is also available for integration into compatible systems. Connections for remote control or display are also provided. Votronic lists the LED Remote Control S and LCD displays, among other items, as suitable accessories. Another function is trickle charging of the starter battery. If, for example, the service battery is being charged via an external AC or solar charger, the converter can supply a trickle current of 0 to 3 A to the starter battery.
Installation and Electrical Design
The charge converter is designed for installation near the on-board battery to be charged. It should be mounted on a clean, level, and hard surface. To ensure adequate cooling, air circulation must be maintained; the ventilation openings must not be covered. There are various connection options, including standard installations as well as integrations into vehicles with EBL/EVS systems. Cable cross-section, cable length, and fuses must be selected to suit the specific installation.
Technical Data
Model: B, without galvanic isolation
Input system: 12 V
Input voltage range (starter battery/alternator): 10.5–16.5 V
Max. input current: 68 A
Adjustable input current limits: 49 A / 42 A / 33 A
Output system: 12 V
Max. charging current: 50 A
Adjustable charging current limit: 39 A
Recommended battery capacity: 75–320 Ah
Battery capacity up to: 440 Ah
Trickle charge for starter battery: 0–3 A
Automatic activation: D+, ignition, or voltage-controlled
Control terminal wire gauge: 0.5–2.5 mm²
Terminal cross-section for battery connections: 4–25 mm²
External temperature sensor: Temperature Sensor 825
Quiescent current: 3 mA
Device cooling: temperature-controlled fan
Ambient temperature range: -20 to +45 °C
Protection rating: IP21
Weight: 950 g
Dimensions (L × W × H): 164 × 139 × 74 mm
Package Contents
1x Votronic VCC 1212-50 CI B2B charging converter
1x Temperature Sensor 825
1x Installation and Operating Instructions
