Mar 25

Understanding and Navigating The 2 Stages of a Mixed Bus Fleet

How to Deal with a Mixed Fleet 

As it becomes increasingly common for bus fleets to transition and integrate more electric vehicles, mixed fleets are becoming more prevalent. There are many factors to take into consideration when dealing with a mixed fleet depending on the stage of the transition and the composition of the fleet. 

From our experience here at ViriCiti with mixed fleet operations, we have seen that it is helpful to divide the mixed fleet transition into two stages. This is helpful because at every stage there are different issues to focus on. 

The Stages of Mixed Bus Fleet 

Stage 1

In stage 1 it is common for there to be a large number of Diesel/ CNG vehicles in the fleet. At this stage, the first electric vehicles are just being purchased. The typical fleet size of the EV fleet is normally less than 10 vehicles. 

Some of the main goals of a fleet in this stage include gathering experiences and understanding new operations and maintenance. From our experience here at ViriCiti we have seen one of the main challenges of a fleet at this stage is figuring out how to operate electric buses within an existing non-EV fleet.

Stage 2

In stage 2, the typical fleet size is a bit larger, normally being composed of more than 10 electric vehicles. At this stage, some of the main areas to consider are the government regulations and the rapid EV market growth. There is generally much more procurement at this stage than in round one. The main goals at this stage are normally to scale up the EV operations. 

Some of the typical challenges around this time are how to secure operations while scaling up and how data can be implemented to overcome these challenges in this stage, in addition to all stages of EV development. 

Management of a Mixed Fleet 

When it comes to the management of a mixed fleet there are several aspects to take into consideration such as energy management, power management, and maintenance. These management and maintenance issues differentiate depending on what stage the mixed fleet is at.

So what does all this mean for you?  To make it easier we will delve deeper and try to unpack some of the most important things you should be considering for every aspect. 

Energy Management 

Stage 1:

In this stage, range anxiety is one of the main issues. In terms of energy management, it is important to understand how external factors affect the range of your buses

💡The operations team should be responsible for monitoring the range, as this basic data set is essential to operate new EVs.

Stage 2

In stage 2 the range behavior is understood and the driving behavior becomes more important once the EV fleet grows. Monitoring your drivers’ behavior can help pinpoint if there are places they can improve for maximum efficiency.

Additionally, when it comes to scaling your fleet, it generally means there are now several OEMs who likely have different range calculations and performance. 

💡The key takeaway is to make sure you have the same data basis to avoid conflicts in range calculations and performance from the different OEMs! 

Power Management 

Stage 1: 

When it comes to charging the new electric buses, one of the decisions that need to be made is whether to use depot charging or opportunity charging. It is also important to understand the energy bills involved. 

At this stage, unmanaged processes are generally sufficient so smart charging is not necessary. However, it is recommended to have a monitoring tool in place. 

Stage 2

At this stage, more factors are becoming important within the fleet approach such as peak demand charges and day/night tariffs. Managed charging processes are essential at this point. 

💡You should consider using a managed charging process such as smart charging, which allows you to lower charging costs and avoid peak demand charges. 


Stage 1:

For maintenance teams, it is essential to understand the state of the battery. The battery is a complex system consisting of hundreds of cells. And the weakest cell/module sets the limitations of the battery.

Key Take-Away!!  Monitoring battery technology becomes an essential part of the maintenance tasks in order to maintain battery health!

Stage 2:

Battery degradation strongly affects the overall fleet performance and it is important to monitor the degradation and state of health of bus batteries. Maintaining battery health is crucial at this stage. The battery is one of the largest investments of your EVs. 

💡Battery reporting is a great tool to keep your millions invested in batteries safe for a second-life investment. 

About The Author

We are the ViriCiti marketing team. A group of EV enthusiasts writing about the most important aspects of operating electric fleets. From monitoring to smart charging.