ARCO Zeus A225S Alternator

SKU: A225S-12-DF315-EX-49K6

Sale price$897.00
Re-stocking on July 10, 2024
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  • Engineered for High Energy Production.
  • Suitable for Marine, RV, Military, and Commercial applications.
  • Rapidly charges large battery banks.
  • Coolest operating temperatures for increased performance. Runs 8 - 20% cooler than incumbent alternators due to:
    • Heat shedding coatings
    • Rectifier located on housing exterior
    • Dual cooling fans
    • OEM Components
  • Optimized for performance at idle speeds.
  • Reduces need for generator by creating additional power with your engine.
  • Unleash peak performance with E-Coat/Cerakote. Our advanced coating absorbs less heat, keeping the A225S cooler. This translates to more amperage for sustained periods.
  • For maximum performance or lithium battery charging, use an ARCO Zeus Bluetooth alternator regulator.
  • SAE J1171 Certified.
  • Proudly made in the U.S.A.

Click here to optimize your alternator's output with the ARCO Zeus Bluetooth alternator regulator.

Voltage 12V
Field Type P
Rotor Poles 16
Stator Size 130mm
Frame Size Small
Weight 12 lbs / 6.7 kg
Regulation Internal/External (IE) or
External Only (EX)
Output Voltage 14.1V (default)
Finish (Black) Cerakote or E-coating
Cut-In RPM 1,061 Alternator RPM
Maximum Alt RPM 19,000
Battery Post M8 Thread Post, Side Mount
Standard Pulley 49K6 (6-groove, 49mm)
Pulley Mount 17mm diameter shaft, 25mm long, threaded M17 x 1.5
Pulley Hardware M17 x 1.5 x 24mm nut, w/ 18mm ID x 29mm OD washer (Included)
Diodes 6 positive, 6 negative, 50A Rated, Avalanche
Max Output (Cold, 9,000 RPM) 254 Amps
Sustained Cruising Output
(Hot, 6,000 RPM)
187 Amps
Sustained Idle Output
(Hot, 3,000 RPM)
157 Amps
Mounting ARCO Part Number Application
1-2” Single Foot A225S-12-SF12-EX-49K6
Replaces most domestic styles using a single 1or 2”mounting foot
(e.g., Motorola, Prestolite).
3.15” J180 Saddle A225S-12-DF315-EX-49K6
Replaces most small case styles using a 3.15” J180 saddle style mount
(e.g., Hitachi, Lucas, Mitsubishi) Most Yanmars.
Vortec/GM A225S-12-VT-EX-49K6
Replaces Mando type alternators using Vortec/ GM pad mounting feet
(Found on many Mercruiser and Volvo Penta 3.0GLM, 3.0GLP, 4.3GXi, 5.7GiL, 5.7GXiL Marine Engines.)
(GM Blocks )

External Only (EX): These units will come with a terminal block and a P-Type harness. They will only work with an external regulator, such as an ARCO Zeus Bluetooth alternator regulator.

Internal/External (IE): Internally regulated with adaptor for optional external regulation.

To measure sustained output, the alternator is run at 3,000 RPMs for 60 minutes with a plexiglass shield covering the units. Testing shows that after 60 minutes in these conditions, alternators reach their maximum operating temperature, or the conditions under which the unit will produce the least output.

It is under these harsh conditions where we measure the “hot” output of the units at various RPMs. The complete power curve is shown above.

Note: The “hot” conditions are much less favorable than the conditions typically used in the industry. The temperature of the stator during our “hot” test was 305 °F. Incumbents measure the power curve at an ambient temperature of 140 °F. “Cold” testing was done at 71° F.

ARCO Zeus A225S APS Mechman Balmar
A225S-12-DF315-EX-49K6 255HSB1H652S9E4 - -
A225S-12-DF315-IE-49K6 - - XT-CR-170-K6
A225S-12-SF12-EX-49K6 - - -
A225S-12-SF12-IE-49K6 - M7294170 XT-SF-170-K6
A225S-12-VT-EX-49K6 - - -
A225S-12-VT-IE-49K6 255HGM1H652S9 M8237170 XT-VT-170-K6


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