REDARC SBI12-BLD BMS load disconnect isolator12V 100A load disconnect solenoid for REDARC Manager BMS

Overview

The SBI12-BLD is the load disconnect solenoid designed to be controlled by a REDARC Manager BMS such as the Manager30. Its black earth wire connects to the BMS load disconnect pin, so the BMS decides when non-essential loads are switched off, using the level set on the RedVision display. As a safeguard the isolator also applies its own thresholds of 10.2V on, 10.0V off and 9.0V instant off. It carries 100A continuously, 400A inrush, and fits a 75×70×80mm, 200g housing.

• 12V nominal, 100A continuous, 400A inrush
• SBI12-LLD: off at 10.5V, back on at 11.0V
• SBI12-BLD: switched by Manager30 load output
• Disconnects loads above 16.5V and on contact voltage drop
• Under 0.1A operating, under 5mA standby
• 75×70×80mm, 200g, 2-year warranty

How it works

Both units sit between the auxiliary battery and the loads it feeds. When the battery voltage stays at or below the turn-off level for the set delay, the solenoid opens and the loads are cut; when it recovers to the turn-on level for the on delay, they are reconnected. The delays stop the contacts chattering when a large load pulls the voltage down briefly.

The SBI12-LLD works on its own and is tuned for LiFePO4 batteries: it disconnects at 10.5V after 2 seconds and reconnects at 11.0V after 10 seconds, so the battery stays above the point where its internal protection would trip and block many chargers. The SBI12-BLD is driven by a REDARC Manager BMS: its black wire goes to the BMS load disconnect pin, the BMS decides when loads are on, and the isolator adds its own 10.2V on and 10.0V off thresholds plus an instant off at 9.0V.

Key features

Both models share the compact Smart Start housing of 75×70×80mm and 200g, with silver solenoid contacts rated 100A continuous and 400A inrush. Operating current is below 0.1A and standby current below 5mA. Spike-suppression components protect the unit and stop transients from the solenoid coil reaching vehicle electronics. A red LED shows when the loads are connected and flashes fault codes.

Installation and compatibility

Mount the isolator near the auxiliary battery and away from direct engine heat, with a fuse at the battery end of the positive cable sized slightly above the total load current. REDARC suggests its FK40 or FK60 MIDI fuse kits, and the FK100 kit for the SBI12-LLD. Main studs take 5–6.2Nm, and the control terminals on the front must not be connected.

In a Manager30 system the essential loads stay on the battery directly, while non-essential loads run through the SBI12-BLD; the cut-off level for those is set in the advanced settings of the RedVision display. The SBI12-LLD can follow any charger, for example a REDARC BCDC, and an optional push-button on the blue wire can keep loads connected below cut-off. Check that the turn-off voltage suits the battery manufacturer's specification.

Fault indication

Two LED flashes mean the battery has risen above 16.5V; the isolator opens so the over-voltage cannot reach the loads, and reassesses every 20 seconds. Three flashes mean more than 1V has been measured across the contacts for over 30 seconds, from excessive current or poor connections, and the loads are disconnected. Repeated switching usually points to an oversized load or a long cable run between battery and isolator.

Questions and answers