Sterling Power ProLatch-R Zero Volt Drop Latching Relay

The Sterling Power ProLatch-R is not a conventional relay. It has two primary features: low power draw and programmability. Please be aware that this unit requires careful attention to detail and a high degree of patience when programming custom settings; as with any high-current electrical device, professional installation is highly recommended.

Low Power Draw: Conventional relays can consume nearly half an amp when energized. This is insignificant when using a 70A alternator, but can take a big bite out of a solar panel's output, especially under off-peak conditions. The ProLatch-R is designed to lock into position and will not consume power by 'staying on.' The only current drawn is to run the internal software which amounts to about 0.5mA (900x more efficient).

Programmability: The ProLatch-R can be set to trigger 'on' and 'off' at certain voltages according to the user's needs. 'On' voltages can be set from 10.7V - 14.8V (x2 in a 24V nominal system) and the 'off' voltages from 10.4V - 14.5V (x2 in a 24V nominal system). There are also factory preset voltage trigger points which are suitable for 95% of applications. An optional remote control is available which displays input and output voltages along with a selection of alarms.

Features:

Charging mode - Uni / bidirectional - When the ProLatch-R is installed between 2 batteries (e.g. engine starter and auxiliary) it works as a bidirectional voltage sensitive relay (i.e. the trigger voltage on the input or output will activate the relay). The ProLatch-R will latch when the alternator is active allowing current to flow from the starter to the auxiliary via the ProLatch-R. In contrast, if there is a solar cell / wind gen / other charging source on the auxiliary battery bank it will also activate the relay and allow charge to flow to the starter battery. The unidirectional setting triggers the activation of the relay by the voltage on the input stud only.

Battery protection mode - The ProLatch-R can prevent the over charging or over discharging of batteries. In order to prevent over charging, the relay disengages at a preset voltage or a voltage you specify (e.g. 14.4V). Therefore the battery will disconnect from the charging source. Conversely, to prevent battery depletion beyond a certain voltage, the relay will prevent charge from being drawn by the draining source (appliance). The device alerts the user by switching the power 'off' for 10 seconds and then back 'on' for 1 minute.

Engine start protection mode - The ProLatch-R can also be used on vehicles where all appliances are run from one starter battery (due to warranty or footprint reasons) such as trucks, mobility vehicles and vans with inverters etc. This allows your appliances to run safely from an engine starter battery without its voltage dropping below the engine starting voltage. If the voltage drops below the starting voltage the appliance will be cut off.