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Mastervolt Mac Plus 12/48-15 [81203205]


Mac Plus 12/48-15Boost Your Service BatteryToo often, service batteries don’t get the charge they need. This is a problem made worse by smart alternators and start/stop systems, which result in slo... Continue Reading
  • $551.99
    Unit price per 
  • Was $674.99
  • Save $123
SKU: 102913 UPC: 816882023446 Weight: 5.6 lb
Availability: Only 0 left!

Mac Plus 12/48-15

Boost Your Service Battery

Too often, service batteries don’t get the charge they need. This is a problem made worse by smart alternators and start/stop systems, which result in slow and insufficient charges. The Mac Plus 48V and 36V solve that problem. With brand-new bi-directional technology, the Mac Plus can use each side as an input or output, delivering a reliable and consistent charge to both service and starter batteries.

Proven Mastervolt Quality

The Mac Plus uses the proven Mastervolt 3-step+ charge algorithm, delivering a quick and easy charge, even to completely flat batteries. By knowing when the engine is running and providing charge, you can also be sure that the Mac Plus will never drain your starter battery.

A robust design holds up in even the harshest conditions, with battery temperature-optimized charging and high-quality aluminum housing to ensure superior protection against dust and water ingress. The power-efficient design also allows the Mac Plus to operate silently and without a fan.

Total Power Flexibility

With a wide DC input range, the Mac Plus allows all DC sources and can charge two batteries from a single alternator or charger. It supports a full range of chemistries and battery types, including lithium. It also functions seamlessly with modern alternators such as Euro 5 and 6, ensuring proper charging by providing constant power, even when the alternator is inactive.

Parallel configuration of up to ten units will provide over 100 amperes. And advanced high-frequency technology with modern microprocessors ensures minimal power loss when switching from 36/48V to 12/24V and vice versa.

Analog voltage sense ports are also available to compensate for voltage drops and maintain proper charging.

Superior Monitoring & Control

Compatibility with CZone®, NMEA 2000®, and MasterBus delivers truly superior monitoring and control and ensures Mac Plus integrates easily into complete systems. Achieve the best performance possible via various controllers and high-quality MOSFETs. And configure the Mac Plus with ease via MasterAdjust, the CZone configuration tool, or even via the on-board DIP switches.


  • Bi-directional technology
  • Get either 48V or 36V power from a single unit
  • Fast and safe charging, even during short trips
  • Fanless design for silent operation
  • Suitable for flooded, Gel, AGM, and Li-Ion batteries (incl. LiFePO4)
  • Even charges fully depleted batteries
  • Engine run detection protects the starter battery
  • Adjustable current limits to meet Euro 5/6 requirements
  • Voltage stabilization protects sensitive equipment, lights, and loads
  • Parallel operation to obtain charging capacities well over 100 Amps
  • MasterBus, CZone, and NMEA 2000 compatible, with intelligent system monitoring and automation
  • Temperature compensation and voltage sense for an optimal charging result
  • E-Mark/R10 certification for mobile applications
  • Power supply mode offers stable power for sensitive loads
  • Heavy-duty connections for easy installation and quick setup via DIP switches

General Specifications:

  • Battery Voltage Sense: Yes
  • Status indicator: Yes, 3 color double LED
  • Communication protocol: MasterBus, CZone & NMEA 2000
  • Output voltage: 30-60 V DC
  • Nominal output voltage: 36/48 V
  • Output voltage stabilization: 2 % at extremes of temps, load, and input
  • Output voltage ripple (peak-peak): Max. 1 %
  • Max. output power: 900 W
  • Max. output current: 15 A
  • Nominal input voltage: 12 V DC
  • Input voltage range: 8-16 V
  • Max. input current: 60 A
  • Galvanic isolation: No
  • Efficiency: > 95 % (at nom. input voltage, full load); 97 % peak
  • Parallel configuration: Yes, up to 4
  • Alarm contact: Yes, through MasterBus, CZone, DIP Switch, or remote switch
  • Engine run signal input: Yes (active high/active low)
  • DIP switches: Yes, for basic setup
  • Dimensions, hxwxd: 255x165x66 mm, 10.0 x 6.5 x 2.6 inch
  • Weight: 2 kg, 4.4 lb
  • Compliance: CE, E-Mark, SAE J1171, ISO 8846 ignition protected, ABYC & UKCA

Technical Specifications:

  • Battery types: Gel, AGM, Lithium Ion, user-defined
  • Power consumption: < 5 mA, < 10 mA in CZone, < 1 mA in MasterBus
  • Temperature range (ambient temp.): - 25 °C to 60 °C; derating > 40 °C/104 °F
  • Cooling: Natural cooling
  • Protection degree: IP23
  • Protections: Overload, over-temperature, DC short circuit, reversed polarity (fuse)


  • Charger Input - Voltage: 12 VDC
  • Charger Output - Amps: 15 A
  • Charger Output Voltage: 36/48V
  • Box Dimensions: 4"H x 9"W x 15"L WT: 5.6 lbs
  • UPC: 816882023446

Quick Guide (pdf)
Owner's Manual (pdf)
Brochure (pdf)

The Mastervolt Mac Plus 12/48-15 [81203205] is a sensational customer favorite, and we hope you like it just as much.

Inventory Last Updated: Apr 20, 2024

Your product will be delivered from one of these locations below depending on the availability.

Our Warehouses

New Jersey

18 Butler Ave, Bayville, NJ 08721


8918 Sabal Industrial Blvd, Tampa, FL 33619

Shipping will be done via UPS, FedEx or USPS. Courier's standard terms, conditions and policies will be applied on all shipments. Please refer to courier's website for further details. Tracking info will be sent via email or sms to you when your order ships.

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