911 Best-in-Class ~ A Division of Audette Collection

AC High Performance Signal Bulb Kit - Technical Specs

Increased Illumination

Here’s the math supporting the 45% gain in brightness claim...

Standard bulbs
- single filament: 460 lumens
- double filament: 440/35

AC High performance bulbs
- single filament: 677 lumens = +47%
- double filament: 684/46 lumens = +55% / +31%

Current draw and heat generated

The AC high performance bulbs are 29w (single-filament) and 29w/8w (double-filament) at 12.8v. That equates to 32w/9w at 13.5 volts which is what they operate at. Standard "P21W" and "P21/5W" bulbs are rated 26.5w/6.6w at 13.5v.

At 13.5v in the bright mode we have 32w - 26.5w = 5.5 watts difference. In the dim mode we have 9w - 6.6w = 2.4 watts' difference. Which is not enough to cause a problem on the input side (wattage/wiring/switches) or on the output side (heat/lenses/housings).