Super B

SB BDB250 Zoom


Super B external under and overvoltage protector, to secure super B tractions batteries against under- and overvoltage with the lowest possible stand-by current.


Before the BDB-250 becomes operational, it has to determine if a 12V or a 24V system is connected. This means that after connecting the BDB-250, the first thing it does is wait a second before doing anything else. After this, if the input voltage is above 10.0V below and 15.4V, the relay will close. If these conditions are not met, the relay will open.

High voltage

If the input voltage rises above 15.0V, the LED will start blinking to indicate a detected overvoltage. This will continue for 90 seconds after which the relay will be opened and the LED will turn off.
When the voltage rises above 15.4V, the entire “warning” process will be skipped and the relay will switch off immediately.

Low voltage

If the input voltage drops below 10.0V, the LED will blink to indicate an under-voltage situation. This will continue for 90 seconds after which the relay will be opened and the LED will turn off.


When the BDB-250 is switched off and the voltage returns between 11.0V and 14.0V, there are two ways to re-activated it.

If the user has chosen the automatic reset function, the relay of the BDB-250 will be activated directly after a “correct” voltage has been measured. However, when the manual reset function has been programmed, the user has to reset the BDB-250 by hand. This is done by pressing the build-in switch. If an external switch is connected to the remote input, this can also be used to reset it manually. The manner in which the BDB-250 will be reset is programmable by the user. The manner in which this is done can be found under 'Programming'


The user can choose if the BDB-250 is reset manually or automatically. This is done by pressing the programming button and holding it down until the LED flashes. This indicates that the BDB-250 is in programming mode. At this point the button must be released.
When the button is pressed once now, the automatic reset function is selected. If the user presses the button twice, the manual reset is selected.

Approximately 4 seconds after the last time the button is pressed, the LED will blink to show the programmed reset function. (e.g.: If position 2 – manual reset – is selected, the LED will blink twice.)

Technical specifications

SKU 958610031040
Autodetect 12V 8V to 20V
Autodetect 24V 20V to 35V
Current consumption 2mA
Input surge current (100ms) 12V mode 2,6A
Input surge current (100ms) 24V mode 5,0A
Switch current Continues 250A
Switch current Peak 1,500A
Dimensions WxHxD 82x57x120 mm
Weight 370 g