Sterling Power Pro Con Voltage Sensitive Relay

Overview:

This solid state voltage sensitive relay (VSR) will connect two batteries together for charging when the voltage on one of them rises above a  preset level, which is programmable between 12.8 and 13.8 volts. Most VSRs are bi-directional, and will activate when either battery comes on charge, but this model can be set to be either bi-direction or uni-directional. This can be be useful if you want to charge from the chassis battery when the engine is running, but not the other way when a solar charger is connected to the house bank. There is an optional ignition connection, which only allows the relay to activate when the engine is running (or any switch activates it).

Since the relay is solid state, resting current is only 1mA, and only slightly more than that when activated.

There is also a current-limiting version of this device, used to protect circuits when the load might exceed the cabling or source battery's capabilities. Yet another model activates only when ignition feed is present (and does not detect battery voltage).

Unit directional activation:

• Function 1: Charging activated by starter battery voltage increase (engine on). This is the most common setting and the factory default setting. This setting also does not have an ignition feed requirement. This connects the primary and secondary banks based on a voltage in excess of 13.3V being sensed on the primary battery only (the engine starter battery). The 2nd battery bank, once connected would only disconnect when both battery banks drop below 13.0V on both sides. The 13V safety threshold is still activated to protect and seperate the batteries if, or when, the drain that invoked this function (voltage drops below 13V) once the unit has tripped, will not re-engage until the voltage on the primary battery bank (the engine start) has exceeded 13.3V again. No ignition feed required on this setting.
• Function 2: Charging either way (bi directional), based on a voltage rise on either side of the unit (default setting). This function will close the relay at 13.3V sensed on either side of the relay, a good example of this would be the use of a combi inverter charger on the domestic battery bank, because most combi’s only have a single output charging line (to the domestic battery bank) then with this function the unit will charge from the combi to the starter battery bank (in effect giving you 2 outputs from the battery charger) when the combi is on, but also charge from the alternator to the domestic battery bank when the combi is off. In either mode the unit still has the 13.3V on and 13V off mode and the current limit function. No ignition feed required on this setting.
• Function 3: Charging batteries one way only. This function allows a charge to flow from the alternator, or battery to battery charger, or any other charging source to a secondary battery bank, but only when the engine is running. In effect, this mode only allows current flow from the primary source to the secondary, and will continue to flow until either there is an overload threat or a low voltage threat to the primary battery or the engine is shut down. This function requires an extra wire to the unit, an ignition feed, that informs the unit if the engine is running or not.

Voltage parameter activation:
Voltage activation and deactivation parameters can be adjusted using the setup command. Auto 12/24V selection, the unit will auto select the system voltage using the following, if it senses 4 to 16V it will lock to 12V , if it sees 16-30V it will lock to 24V. If for some reason the input voltage is very low (in the case of an empty 24V system), then the product can be disconnected and allowed to re-engage, once locked the product will hold that setting until fully isolated again. Both the VSR and the CVSR unit are fitted with the latest active progressive disconnect algorithm to ensure that the batteries can charge even where large differential voltages exist. As such there will be various time delays between what the customer has preset as the turn ‘off’ voltage point and the product actually turning off. The time delay will reduce the lower the voltage is below the programmed disconnect voltage.