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Model no.
Mastervolt - Laderegler ALPHA PRO III
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Product details

Alpha Pro III: Fast charging, anytime, anywhere.!
The propulsion engine of your boat or vehicles may be used to quickly charge your service batteries, either while cruising or taking a break. The advanced and powerful Alpha Pro III ensures fast and safe charging, protecting both the engine and the batteries. Building on 10 years of experience, the Alpha Pro III features a modernized look, higher power and improved ease of use.

The Alpha Pro III measures the temperature and the voltage of your batteries to prevent overcharging, keeping them in perfect condition. It also monitors the engine load, thus reducing sound variations, wear and tear. The smart ‘keep alive’ feature solves a common problem causing unreliable tachometer readings. Via MasterBus, it communicates RPM, alternator status and charge status to create intelligent power systems.

Get the most out of your alternator
The alternator that comes with the engine is not optimally suited for charging service batteries. Designed for low cost and short charge cycles, it charges at a slow pace and is easily overheated. Replacing the standard regulator* with the Alpha Pro III optimizes this charging process, protects against overheating and overcharging and extends the lifetime of your batteries. 

Super charge your system
For superfast charging at low RPM, Mastervolt recommends to combine the Alpha Pro III with a high performance alternator such as the reputable Alpha series. With 20 amps of field current capability, the Alpha Pro is the only 3-step regulator in the market capable of controlling alternators with outputs up to 400 A!

  • Transforms every alternator into a full temperature controlled 3-step charger.
  • Reduces run time, saves fuel, reduces noise and emissions.
  • Protects from overcharging and extends battery life.
  • Balances engine load, reducing RPM variations.
  • Compatible with standard and high performance alternators, incl. 200 A ~ 400 A models.
  • Integrated ‘keep alive’ feature for reliable tachometer readings.
  • Suitable for every battery type, including Lithium Ion.
  • Suitable for 12 V and 24 V system voltages.
  • Masterbus compatible: simplifies wiring, saves space and weight, and creates optimal cooperation between Mastervolt products.
Application: Applications range from improving the performance of a standard alternator in a vehicle or boat, to generator replacement, when combined with a high performance alternator.

Technical specifications

Link to MasterShunt Yes
Connection with Mastervolt alternator Yes
Connection with Bosch alternator Yes, when using a Bosch adapter cable (optional)
Rated output voltage 12V / 24V
Cable length regulator / alternator 1.5 m / 5 ft oil resistant connection cable
Cable length temperature sensor 6 m
Connector plug controller / alternator Alpha / Mastervolt
Cooling Fanless
Powered by MasterBus Yes
Display LED display
Dimensions, HxWxD 90 x 109 x 30 mm
Weight 0.4 kg
Delivery Battery temperature sensor with 6-meter cable
Certifications CE
Charging characteristic IUoUo, automatic / 3-step + for gel / AGM / wet cell / lithium-ion batteries
Charging voltage bulk / absorption / float Default setting for AGM, gel and lithium-ion batteries (adjustable)
Absorption time 4 hours, adjustable from 2 minutes to 10 hours
Temperature compensation -30 mV / °C
Voltage compensation Voltage drop in DC cables up to 3V
Alternator type Alternators with negative excitation
Field current Up to 20 amps
MasterBus compatibility Yes

  • Replacing the controller is not permitted for EURO 5/6 engines


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