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Suncoast Batteries

12V 20A DC to DC Battery Charger Dual Battery System MPPT - Free Delivery

12V 20A DC to DC Battery Charger Dual Battery System MPPT - Free Delivery

Regular price $189.95 AUD
Regular price Sale price $189.95 AUD
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20A DC-DC Battery Charger (12V) with MPPT – AGM & Lithium (LiFePO₄)

🚚 FREE DELIVERY AUSTRALIA WIDE  
🔋 Alternator + Solar Dual Input  •  🧠 Smart-Alternator Compatible

Keep your aux battery topped up—anywhere. This compact DC-DC charger pulls power from your vehicle’s alternator and from solar via a built-in MPPT regulator, so you arrive with more charge and less engine load. It supports AGM, Gel, Calcium, VRLA, Flooded and Lithium (LiFePO₄) batteries, works with modern smart alternators, and uses multi-stage charging to maximise battery life. A pulse-recovery routine helps revive deeply discharged batteries, while comprehensive protections keep your system safe on the rough stuff.

Key Features

  • Dual Input: charges from the vehicle alternator or from solar panels (built-in MPPT).
  • Smart Alternator Compatible: ACC/ignition wire control for correct cut-in/cut-out on modern vehicles, caravans and trailers.
  • Built-in MPPT: optimises solar harvest to reduce engine load and shorten charge times.
  • Pulse Charging Algorithm: selects optimal modes and helps recover deeply discharged batteries.
  • Multi-Stage Charging: bulk → absorption → float for efficiency and longer battery life.
  • Multi-Chemistry Support: AGM, Gel, Calcium, VRLA, Flooded & Lithium (LiFePO₄).
  • Comprehensive Protection: over-charge, short-circuit, over-temp/thermal load, solar input overload, input/output reverse-polarity.
  • Internal Temp Monitoring: protects electronics and improves reliability.

Detailed Specifications

Type Multi-Stage 12V DC-to-DC
Features MPPT solar input, Smart-alternator compatible
Models 20A / 30A / 40A
Suitable Battery Types AGM, Gel, Lead Acid, Calcium, LiFePO₄
Recommended Battery Range 60–600Ah (20A) • 90–900Ah (30A) • 120–1200Ah (40A)
Inputs Alternator/DC: 13–16V  •  Solar (MPPT): 16–25V
Output / Charging Voltage 13.5–15.4V (stops charging when alternator/vehicle battery < 12.4V)
Max Output Current 20A / 30A / 40A (by model)
Minimum Start Voltage 2.0V (battery being charged)
Soft Start Yes
Bulk Charge Voltage AGM/Gel: 14.7V  •  Lead Acid: 14.4V  •  Calcium: 15.4V  •  LiFePO₄: 14.6V
Absorption Constant voltage with automatic amperage control
Equalisation Automatic
Float Voltage 13.5V (AGM/Gel/Lead Acid/Calcium)
Float Current 100mA

Cable Gauge Guide (Minimum)

Run Length 20A Model 30A Model 40A Model
0–1 m 11 AWG 8 AWG 8 AWG
1–5 m 9 AWG 6 AWG 6 AWG
≥ 5 m 7 AWG 4 AWG 4 AWG
Note: Select the correct battery type before connecting the auxiliary battery. Confirm cable size & fusing for the model current (20A/30A/40A). Use ACC/ignition wiring for smart-alternator vehicles. For LiFePO₄, ensure your BMS allows the chosen charge profile. Charging voltages quoted at ~25 °C.
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Why Buy From Suncoast Batteries?


At Suncoast Batteries, we’re proudly Australian-owned and locally operated, with a team of real people ready to help whenever you call. We’re not just an online store—we’re your neighbours, dedicated to giving honest advice, fast local service, and genuine support. When you buy from us, you’re supporting an Australian business that understands the unique demands of our climate and vehicles—and cares about keeping you powered up wherever you go on your adventures.

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