420-amp H.O. Alternator

Delco Remy 55SI Alternator Kicks Out 420-amps

Delco Remy now offers its most powerful and efficient alternator — the 55SI. This brushless design unit is rated at 420 amps at 12 volts and up to 275 amps at 24 volts. 

One 55SI can replace a dual alternator system, freeing up space under the hood for other accessories. It also supports the electrical load requirements of long haul trucks equipped with multiple battery auxiliary power units (APUs). 

“The 55SI is the highest output Delco Remy alternator—not to mention the highest output machine in its class,” says Eric Bippus, Senior Vice President, Remy International Aftermarket Sales and Marketing.

“No other alternator can provide this combination of performance, a brushless design and an efficiency rating of 80% in this frame size.”

The 12-volt 420 amp model is commonly used in the aftermarket on fire and rescue trucks due to its desirable compact design and high-output performance at engine idle. 

The 55SI is available today on new fire truck orders at all original equipment manufacturers (OEMs).

It is an ideal application for utility and work trucks in order to power inverters and plug-in power tools, lights and other electrical equipment.