APC Filtration Inc. works with global OEMs of hybrid transportation equipment to design, engineer, manufacture and test develop custom air filter solutions for their specific requirements.


A Tier 1 battery manufacturer required a high performance air filter required to for cooling a roof mounted battery pack for Hybrid transit buses. They needed a panel filter design with the ability to capture 85% of 0.5 micron particles with a 0.22″ pressure drop and needed prototype filters for testing in two weeks.

APC manufactured two different prototype filters within 7 days for client testing. Based on their feedback, a third prototype filter was made to fine-tune filter efficiency, pressure drop, and operational temperature requirements. Initial filter testing and prototype filter submission was completed within a 4 week time frame.

The next phase required 20 prototype filters for 6 month field testing:

  • Test 1: New York City. Wintertime testing subjected the filters to sub zero temperatures, wind, snow, sleet, ice, and road salt.
  • Test 2: Arizona. Filters subjected to superfine Arizona road dust, below 0.5 micron, and high operating temperatures.
  • Test 3: California. Filters subjected to sea salt spray, heat, battery draw and stress from steep roads.

All three tests challenged the filters’ air cooling and filtration capabilities to keep battery cells clean and operating temperatures in check to maximize battery performance.