Charger integration and charging behaviour
One of the first things to consider is how the charger is connected to battery, the AGV and the fleet management system. Being able to connect the charger via CAN communication is highly recommended, as it improves safety and makes it possible to get better performance and lifetime out of the battery as well as the charger.At the same time, it is important to look at how charging fits into the operation itself. A key factor here is opportunity charging, allowing the AGV to charge when it has time to do so. Instead of relying only on dedicated charging periods, the AGV can charge whenever there is an available window.
This makes charging something that can take place throughout the operation, rather than being limited to specific stops.
Charger selection and fleet requirements
Another important consideration is the choice of charger. Some chargers today are designed to be more flexible, and with CAN communication, the same charger can be used for different AGVs, voltages, and battery types.This becomes particularly relevant in environments where different types of AGVs operate together. In these cases, the ability to support a mixed fleet with the same charging setup is an important factor.
The capacity of the charger also needs to be considered. It must be correctly sized to support the fleet and avoid limitations in operation.
Battery sizing and system performance
Battery selection always involves trade-offs between energy density, performance, and cost, and this requires repetitive evaluation from an overall system and fleet perspective based on the application.One important aspect in AGV applications is energy density. A higher energy density allows the battery to take up less space and reduces weight, which allows to design for a smaller AGV footprint, increase the payload capacity, and have a positive effect on performance.
At the same time, it is important to consider how much usable energy is delivered over the system's lifetime. If a larger battery can be accommodated within the same space, it becomes possible to operate within a more favorable state-of-charge range over time, which can have a significant positive impact on battery life.
In addition to extending battery lifetime, a higher-capacity battery can provide a valuable buffer during periods of peak demand throughout the day. It also enables charging to be scheduled at more suitable times and supports more robust operation by mitigating some of the risks associated with vehicles becoming stranded due to a low state of charge.
Battery systems with multiple modules also introduce additional complexity. Keeping those modules balanced can be a challenge, especially when they are connected in series or parallel. In this context, one larger battery can contribute to a more robust system.
Charging in operation: AGV and AMR differences
Finally, charging behaviour also depends on how the AGV operates.An AGV typically operates within a fixed structure with predefined missions, while an AMR has more flexibility and can make decisions during operation.
For example, an AMR can stop and opportunity charge when it passes a strategically located charging point between missions. In that case, charging becomes part of the operation itself, minimizing transfer time and reduces the need of traditional charging locations or dedicated rooms.
These are some of the key variables to consider when looking to improve efficiency and reduce downtime related to charging.
