ARCO Zeus A4000-24V Low Turn On (LTO) High Output Alternator - Isolated Ground

If Optimal Charging at Low Speed is Important to You, This is the Perfect Alternator for You

High Output / High Amperage Alternator: The Highest Power Output in Its Class
Note: If fast idle charging is important to you, view our ARCO Zeus 24V 7kW High Amperage Alternator here.
24V Advantage - Low Turn On (LTO)
The ARCO Zeus A4000-24V LTO alternator turns on at lower RPMs, runs cooler and provides more power than older designs that are larger and heavier. This alternator continuously generates over 1.4kW (51 Amps) at just under 1,500 RPM, and almost 2.4kW (87 Amps) at 2,000 Alternator RPM. Put in real world terms, a marine diesel engine idling at 750 RPM with a 2:1 pulley ratio is generating over 1.5kW (55 Amps), and a Mercedes Sprinter at 750 RPM with a 3.21:1 ratio is generating over 2.5kW (91 Amps)!
Best-in-Class Performance
The ARCO Zeus A4000-24V alternator turns on at lower RPMs, runs cooler and provides more power than older designs that are larger and heavier. The newest generation of 24V performance has arrived.
True 24V Alternators
Competitor’s 24V alternators utilize a 12V rotor and field current which is less efficient and limits output at all RPMs. ARCO utilizes a native 24V rotor and field current. This results in our 24V alternator running cooler than competitor’s 24V alternators, having a direct impact on alternator lifespan.
ARCO Zeus 24V High Amperage Alternators, A4000-24V LTO or A7000-24V: Which One's Right for You?
Choose A4000-24V LTO if:

You prioritize charging at idle (at campsite or anchor)
You need to limit power take-off i.e. smaller engine
You are willing to trade some top-end output for increased outputat low RPMs

*On the power curve graph, select A4000-24V LTO for use cases left of the Decision Point; otherwise, select A7000-24V.
Here’s a concise comparison of the DF315, DF4, and SF12 ARCO Zeus alternator mounting configurations:

Mount Code
Mount Type
Foot Style
Foot Spacing
Common Use
Notes

DF315
Dual Foot (Yanmar-style)
Dual
3.15 inches (80 mm)
Yanmar marine engines
Stable, compact mount for tight bays


DF4
Dual Foot (J180-style)
Dual
4 inches
Heavy-duty marine and industrial engines
Rigid, robust mounting

SF12
Single Foot (Universal, Delco Style)
Single
1" or 2" (adjustable)
Flexible marine/automotive applications
Adapter allows fit to multiple brackets

DF315 is ideal for Yanmar-style brackets.
DF315R is ideal for Yanmar-style brackets. R = Rear Battery Post
DF4 is suited for larger, more robust engine frames.
SF12 offers the most flexibility and is often used in retrofits or tight spaces.