Nissan Altra EV headlight bulbs utilize H1 size bulbs for both high beam and low beam functions. The replacement chart covers vehicle production spanning 1999 to 2001.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The H1 bulb is a single-filament halogen type with a P14.5s base, operating at 12 volts and 55 watts. It conforms to the ECE standard, which governs automotive lighting regulations across Europe and numerous other markets worldwide, and holds approval in the United States and Japan as well.
The P14.5s base designation refers to a single-contact prefocus base with a 14.5mm body width, a design that physically locks the filament in a fixed position relative to the reflector to maintain consistent beam alignment.
The Nissan Altra EV uses the H1 bulb size for both the high beam and low beam headlight positions across the 1999-2001 model years.
Because both beam positions share the same H1 specification, the bulbs are physically interchangeable between sockets, though each socket serves a distinct optical function within the headlight assembly.
The single-filament construction of the H1 means each bulb serves only one lighting function. Vehicles requiring separate high and low beams therefore require two H1 bulbs per headlight housing rather than a single dual-filament unit.
At 55 watts, the H1 operates within the standard wattage range for halogen headlight bulbs, a figure that reflects a balance between light output and the thermal and electrical tolerances of typical automotive headlight housings.