REDARC BCDC Dual Input Multi-Stage In-Vehicle Battery Charger

1.1 Display Panel

The front panel features 7 LEDs that display the Charge Profile and Charge Status. These LEDs indicate the selected charging profile and the current stage of the charging process.

1.2 Charge Profile LEDs

Four different charging profiles are available to suit various battery requirements. The selected profile LED remains solid when the unit is ON and charging. A flashing profile LED indicates standby mode.

1.3 Charge Status LEDs

The Charge Status LEDs indicate input availability and charging stage. The 'Solar' and 'Vehicle' LEDs are ON when the respective input is available and in use. If both are ON, both sources are active. The charger utilizes Green Power Priority technology, prioritizing solar input before supplementing with vehicle input.

1.4 Charging Process

The charging process involves several stages:

• Boost: Maintains constant current until battery voltage reaches Absorption Voltage. Current may vary for temperature or voltage difference management.
• Absorption: Maintains constant voltage for a set period or until charge current drops below 4 A for 30 seconds.
• Float: Maintains a topping-up voltage (13.3 V or 13.6 V for LiFePO4) to counteract self-discharge or loads. The charger returns to Boost if the battery loses charge.

Diagram Description: A graph shows Voltage rising through Boost and Absorption stages, then leveling in Float. Current is shown as constant during Boost, decreasing during Absorption, and minimal during Float.

The charger includes automatic timeouts to prevent overcharging. If a timeout occurs before full charge, the process may restart from Boost after a 'rest-period'.

1.5 Soft Start Charging Process

The BCDC1250D features a Soft-Start stage where current ramps from 0 A to full rated current over approximately 30 seconds before entering the Boost stage.

Diagram Description: A graph illustrates the Soft-Start stage where current gradually increases, followed by Boost, Absorption, and Float stages.

1.6 Turn On/Off Thresholds

The charger has specific voltage thresholds for turning ON and OFF based on input source (12V Vehicle, 24V Vehicle, Solar) and trigger settings (Standard, Low Voltage).

*1 Tested every 100 seconds | *2 Tested constantly. A maximum 20-second delay applies before output is produced.

1.7 Error Codes

In case of a fault, all LEDs flash to indicate the type of error.

*3 Specific source LED flashes 5 times if one source is undervoltage when both are active; ALL LEDs flash 5 times if both sources are undervoltage or if only one input is undervoltage.

1.8 Battery Test Mode

The unit performs a battery test every 100 seconds to verify input conditions and check for a battery on the output, protecting against over-discharge and connection damage. This test can take up to 60 seconds.

2.1 Install Location

Use REDARC BCDC Mounting Brackets for easy installation. The heatsink can reach up to 60°C / 140°F; install the unit away from users and flammable materials. Optimal operation is below 55°C / 130°F with good airflow. Higher temperatures cause de-rating up to 80°C / 175°F, at which point the unit turns OFF. Suitable locations include the cabin, chassis rail, or engine bay (away from high heat). Keep cable length to the auxiliary battery under 1 meter. Mount the charger in any orientation using the heatsink tabs.

Diagram Description: An illustration shows the BCDC unit with four mounting tabs on its heatsink.

2.2 Charge Profile Selection - Orange Wire

Connect the ORANGE wire to set the maximum output voltage according to your selected Charge Profile and installation environment (Cabin or Engine Bay).

CAUTION: Ensure the selected charging profile's maximum voltage does not exceed your battery manufacturer's recommendation. For LiFePO4 batteries, ensure they have an inbuilt battery management system.

Diagram Descriptions:

• Profile A: ORANGE wire disconnected and taped (14.6 V).
• Profile B: ORANGE wire connected to Common Ground (15.0 V).
• Profile C: ORANGE wire connected to RED wire (15.3 V).
• Li Profile: ORANGE wire connected to GREEN wire (Lithium mode).

2.3 Input Trigger Settings - Blue Wire

Connect the BLUE wire to select the vehicle input turn-ON trigger mode:

• Standard Trigger: For fixed voltage or temperature compensating alternators. Connect BLUE wire to Ground or leave disconnected.
• Low Voltage Trigger: For variable voltage alternators. Connect BLUE wire to D+ (Idle-stop) or IGN (continuous idle).

*1 Tested every 100 seconds.

2.4 Cable Sizing

Refer to the table for recommended cable thickness and length for Vehicle Input, Solar Input, Ground, and Battery Output. Always select a wire cross-sectional area equal to or greater than specified.

2.5 Wiring

The unit's heavy gauge wires carry peak currents up to 55 A. Ensure good, low-resistance electrical connections to prevent degradation, short circuits, or fire. Soldered butt splice crimp connections covered with heatshrink are recommended over standard blade connections.

Diagram Description: Illustrates crimping wires to a butt splice using single-indent crimpers, followed by soldering the connection and applying heatshrink.

2.6 Fusing

REDARC recommends MIDI style bolt-down fuses (FK40 and FK60 kits) for low-resistance connections. Blade type fuses and self-resetting circuit breakers are not recommended due to potential high resistance, excess heat, and premature tripping.

Diagram Description: Shows a MIDI style bolt-down fuse assembly.

2.7 Typical Setup

Installation should be performed by a qualified person. Refer to Cable Sizing (Table 2.4.1) for requirements.

2.8 Connecting Solar Panels - Yellow Wire

The YELLOW wire is for optional solar input. Do not connect regulated solar panels; the BCDC has an inbuilt regulator. Multiple solar panels should be connected in parallel to maintain voltage while increasing power. The BCDC limits power if panels exceed maximum needs.

Note: Most house panels have a 32 V open circuit voltage limit, making them unsuitable for this charger.

Diagram Description: Illustrates connecting multiple 12V solar panels in parallel using Y-connectors to the BCDC unit, showing positive (+) and negative (-) terminal connections.

No LEDs ON at all

Indicates no battery connected to output or battery is not at a suitable voltage, AND input is not connected. Check all wiring (especially Ground - BLACK wire) and fuses.

The Charge Profile LED is flashing

Indicates invalid output or input. Either the auxiliary battery is connected but has no valid charging source, or a valid source exists but the auxiliary battery voltage is too low or disconnected. Check Vehicle (RED) and Solar (YELLOW) connections, Ground (BLACK) connections to auxiliary battery and chassis earth, and fuses.

I have Solar connected but the Solar LED is OFF

Required turn ON conditions not met. Solar Open Circuit Voltage may be below 9 V, or insufficient power is available. Check sunlight levels, shading, voltage at YELLOW wire (must be > 9 V), wiring, and ensure an unregulated solar panel is used. Allow 2 minutes for recognition.

The BCDC is connected to the Vehicle but the Vehicle LED is OFF

Required turn ON conditions not met, or Solar input is meeting all power requirements. Check if the vehicle is running. Verify voltage on RED wire meets turn ON thresholds (refer to Table 1.6.1). Check all wiring to the vehicle battery, especially the Ground (BLACK) wire.

The BCDC Dual Input turns ON at 12.9 V (12 V) and OFF at 12.7 V (11.9 V), but you say it operates down to 9 V, please explain?

The charger briefly turns OFF every 100 seconds to measure unloaded battery voltage. If this measured voltage is below 12.7 V (11.9 V), it turns OFF. At any other time, if the voltage drops below 9 V, it turns OFF.

How does the BCDC Dual Input charge an Auxiliary battery at 14 V when it only gets 9 V in?

The BCDC Dual Input acts as a reducer and booster, operating from voltages above, equal to, or below the desired output. Its microprocessor-controlled REDARC proprietary charging algorithm allows it to charge specific battery types even with low input voltage.

Where should I mount the BCDC Dual Input Unit?

Mount as close as possible to the auxiliary battery. In engine bays, choose locations away from direct engine heat. In caravans/campers, near or in the battery compartment is ideal. Mounting to a metal surface can aid heat dissipation.

What does the charger do if the temperature around it rises above its operating temperature?

The output current capacity is gradually decreased to protect both the battery and the unit.

If I use the BCDC Dual Input to charge my auxiliary battery do I still need to install a battery isolator?

No, the BCDC Dual Input incorporates battery isolator functionality. It turns ON when the vehicle starts and OFF when the vehicle is turned OFF.

I've heard that you shouldn't charge 2 batteries of different chemistries from the same source, will I have any problems charging my AGM or Gel auxiliary battery from my Lead Acid start battery?

The BCDC is a DC-DC charger, not a battery isolator. Its output is tailored to the selected auxiliary battery type, allowing optimal charging regardless of the start battery's chemistry.

My BCDC Dual Input is setup for 12 V Alternator input but will not start when the vehicle is turned On, I've followed the trouble shooting guide and the setup is fine, what's the problem?

The issue may be that the unit is stuck in 24 V mode. Try removing and reconnecting the Vehicle (RED) wire. Alternatively, the input voltage might be too low; check it against the thresholds in '1.6 Turn On/Off Thresholds'.

Can the BCDC Dual Input charge from Solar and Vehicle power at the same time?

Yes, it prioritizes solar input and supplements with vehicle input when both are available.

Can the BCDC Dual Input operate with only a single power source input?

Yes, it can operate as a stand-alone solar regulator (Solar wire only) or a DC charger (Vehicle wire only).

Contact Information

Australia, New Zealand & Europe:
www.redarc.com.au/warranty
REDARC Electronics Pty Ltd
23 Brodie Road (North), Lonsdale SA 5160, Australia
Phone: +61 8 8322 4848 (Australia), +64-9-222-1024 (New Zealand), +44 (0)20 3930 8109 (UK & Europe)

North America:
www.redarcelectronics.com/warranty
REDARC Corporation
c/o Shallco, Inc.
308 Component Dr.
Smithfield, NC 27577 USA
Phone: +1 (704) 247-5150 (USA), +1 (604) 260-5512 (Canada), +52 (558) 526-2898 (Mexico)

Checking the Product Serial Number

The Product Serial Number is located on the Main Unit and on the product packaging.