Link Transit and Electric Buses
Link Transit was an early adopter of battery electric buses and proportionate to our size, operates the largest battery electric fleet in the nation. In 2009, the Federal Transit Administration (FTA) awarded a Link Transit a $2.95 million dollar grant to acquire five (5) 22 foot long battery electric replica trolley buses and robotic fast chargers.
These buses and the affiliated charging equipment (the Green Trolleys you may have seen in our downtowns) were delivered to Link Transit between 2011 and 2014. These buses have been very popular with our guests due to their look and their very quiet operations.
These five buses are the first battery-electric buses and the first robotic, high powered chargers ever installed and used in the Pacific Northwest. These buses were the first smaller (22') buses to ever be equipped with Lithium-ion batteries and to be equipped with air conditioning, electronic head signs, and low floor accessibility features. These buses were truly cutting edge and technological marvels.
Unfortunately, new technologies tends to bring new problems and we have had our share. The first batteries, a Lithium-ion, Titanium Oxide chemistry suffered from electrolyte leaks. This forced our manufacturer (EBus Inc) to redesign the battery system. During this 18 month period, they repowered the buses with older style Nickle Cadmium batteries. These batteries took a lot of maintenance and could only operate ½ of a day, but provided reasonable service. By late 2014, our vendor delivered to us the five buses with Lithium-ion, Iron Phosphate batteries. The repowered buses provided 90 kilowatts (KW) of power on the bus and could be recharged with our robotic chargers at rate of 72 KW per hour of charge.
We began using this technology in partial service in the fall of 2014 and full service in early 2015. While the buses were functioning per specifications, they were failing at much too high a rate. Between the four buses in regular daily service (fifth was rotated in a spare and for maintenance) we were seeing a fault or failure with our charger about once per day. We were also seeing an electrical fault on one of the buses every four days. These faults required the replacement of a charge circuit board that required two days of labor to achieve. These high failure rates were a major challenge and our vendor did not have an effective solution. We discovered another problem with high summer heat. We experienced batteries over heating in the afternoons.
After struggling with this problem in 2015 and again in 2016, we determined that we could not fast charge the buses when the temperatures were over 95 degrees F. This reduced the range of the buses to about 90 miles, which was not adequate to complete a full days operations. However, by not using the fast chargers, we noted that our circuit board failures disappeared. By September of 2016, we decided to suspend the use of the fast chargers and just run the trolleys ½ day. This strategy worked well during the nice days of fall. However, by mid-December, we discovered that the trolleys no longer had 90 miles of range. It appeared that when the temperature was below 35 degrees, the batteries would only provide us about 45 miles of range. Without the heat that fast charging produced, the batteries would not work in the cold. After struggling with a solution, we decided to park the vehicles for the coldest part of the winter.
We began using the buses again in early March of 2017 and used them until the first week of December 2017. We anticipate returning them to service in March of 2018 and plan to use them in this manor until they meet their useful life requirements.
In a future article we will share our experiences with our second generation electric buses.