REDARC BCDC1225D DC to DC Charger 25A 3-Stage - 9V-32V In, 12V Out, Dual Input MPPT Regulator

Keep your 12V auxiliary battery charged properly, wherever the track takes you. The REDARC BCDC1225D 25 Amp DC-DC charger delivers smart, multi-stage charging from your vehicle's alternator, engineered specifically for the demands of dual battery setups in 4WDs, camper trailers, and caravans.

Compatible with 12V and 24V vehicle systems - the BCDC1225D accepts input from either a 12V or 24V alternator and charges a 12V auxiliary battery, making it suited to both standard and heavy-vehicle electrical systems.

Why you need a DC-DC charger, not just a battery isolator

Modern vehicles with smart alternators don't output a consistent voltage, which means a basic isolator often can't fully charge your auxiliary battery. The BCDC1225D solves this by using DC-DC conversion to deliver a genuine multi-stage charge regardless of what your alternator is doing - so your second battery actually reaches full charge, not just "close enough."

Key features:

• 25A charge rate - ideal for a 12V lithium or AGM auxiliary battery, suited to battery banks in the 75-200Ah range
• 12V or 24V alternator input - charges a 12V auxiliary battery from either a 12V or 24V vehicle system
• Dual input - charges from the vehicle's alternator or an unregulated solar panel via built-in MPPT solar regulator
• Compatible with smart alternators - maintains full charging performance even with variable-voltage charging systems
• Multi-stage charging algorithm - bulk, absorption and float stages for maximum battery life
• Suits AGM, GEL, Calcium, and Lithium (LiFePO4) batteries - select the correct profile via the onboard switch
• Ignition-controlled - auto engages when the engine starts, no manual switching required
• IP67 rated, sealed housing - built to handle vibration, dust and moisture in tough off-road conditions

Typical applications:
Dual battery systems in utes, 4WDs, camper trailers and caravans (including 24V commercial and heavy vehicles) running fridges, lighting, and other 12V accessories off-grid.

In the box: BCDC1225D unit and wiring diagram (fuses and battery cabling sold separately based on your install length/run).

Note: this unit charges a 12V auxiliary battery only — it does not output 24V.