As the transition to wider commercial EV adoption continues, fleet operators are in the middle of hardware evolutions, changing mandates, market disruptions, and more. For this reason, it makes sense for fleet managers to work with several providers when it comes to vehicles and chargers in order to meet their unique needs and operate their businesses. On the other hand, when problems arise, the multiparty nature of EV operations can make it difficult to get to the bottom of the issue and find a timely solution.
Luckily, Synop can provide the necessary data and leverage built trusted relationships with partners to uncover the root cause and pinpoint a resolution. This case study highlights how Synop worked collaboratively with Thomas Built Buses (TBB) and Delta Electronics to help Kerlin Bus Sales & Leasing deliver fully charged school buses to the drivers of Monroe County Community School Corporation in Indiana.
Challenge
The depot has 20 2-dispenser, 100kW Delta City chargers, which charge 23 Class C Jouley buses. While the chargers had ample power to recharge the buses rapidly, drivers were reporting that when they arrived at the depot at 6:30 each morning, the buses’ batteries would often be as low as 90% or less State of Charge (SoC) and not actively charging.
To ensure drivers were starting their routes with fully charged vehicles, Kerlin personnel began a daily routine of arriving at the depot at 5:00 in the morning to unplug and replug the buses from their chargers in order to manually force a “top-off” charge.
But as the 2023-2024 school year progressed and the weather got colder, this pre-dawn routine became increasingly challenging. Moreover, Kerlin was concerned about reduced efficiency in the buses if they had to begin driving while their batteries and Battery Management Systems (BMS) were cold. In November 2023, Kerlin approached Thomas Built Buses for advice on how to improve their operations.
The Winding Path Toward a Solution
Based on the specific use case, the Thomas Built Buses Infrastructure Consulting team recommended Synop Charging Management Software (CMS), to optimize charging. When Synop came on board, the first order of business was bringing the chargers online as they weren’t networked at the time. By providing 4G SIM cards and engaging with Delta Electronics’ leadership, electrical contractor, and Thomas Built Buses’s Project Lead for Commercial Charging, Synop was able to configure the chargers to communicate with the Synop platform over OCPP.
It was then through the Synop platform that Kerlin was able to gain clear visibility into exactly what was happening overnight. Each bus’s battery would reach 100% SoC relatively early, typically before midnight, and the charging session would end. Rather than hold the charge, however, the bus was still using energy in standby mode, something all electric vehicles do to some degree, and thus the batteries were not fully charged in the morning.
To address the issue, Synop worked with Kerlin to implement managed charging strategies, such as site limits that would slow charging until 1:00 or 2:00 in the morning. This led to longer-duration sessions that would end in the early mornings, and in fact many buses had higher SoCs at 6:30 am now with Synop than before. Through continued iteration of site limit lengths, Synop was able to make incremental improvements, but Kerlin were still not able to get all of the buses to a 100% charge at exactly 6:30am.
Unwilling to accept less than a full battery at the start of the bus drivers’ shifts, Synop engaged Delta and Thomas Built Buses to determine what was causing the charging sessions to end when the buses reached 100% SoC. Synop had ample evidence that the EV was not exhibiting any abnormal charging behavior with Other Charger being monitored on the Synop platform, so it seemed likely there was some interoperability issue at hand.
With all hands on deck, Synop retrieved charging logs from the chargers over OCPP, while an electrical contractor downloaded low-level diagnostic files from the chargers themselves and shared these with Delta. Delta engineers analyzed the files, agreed that there was a way to keep charging sessions ongoing when the buses reached 100% SoC, and began working on a firmware solution. Meanwhile, Synop remained in contact with Delta and provided Kerlin with regular updates on when the firmware would be ready.
Results
On January 23, Delta provided Synop with an updated firmware file, and Synop loaded this to the chargers over-the-air. Immediately, the charging sessions began remaining active indefinitely. After the buses reached 100% SoC, the chargers would drop to about 1kW and periodically increase to around 10kW for roughly 20 minutes every few hours. In this way, the buses were able to replace any standby losses.
As a result, buses were full and warm in the morning, and Kerlin no longer had to send someone to the site at 5:00am. They were also able to remove the site limits that had previously been put in place as a compensation measure.
The new firmware also led to two added bonuses. Firstly, the chargers, which had previously been very intermittent online, remain stable in their 4G connections. Secondly, the chargers can now send Synop the OCPP tags (MAC addresses) of the vehicles, allowing Synop to match charging sessions to bus numbers, which will enable more tailored charging management in the future.
Through persistence, collaboration, and Synop’s software insights, interoperability issues can be solved.
