With their lower operating costs, reduced emissions, and promise of greater energy independence, the use of electric tractors is gaining worldwide momentum. At the heart of these innovative machines lies a critical component: the battery management system (BMS). The electric vehicle BMS ensures that the tractor battery, the power source for these off-road vehicles, operates efficiently and reliably in demanding agricultural and land management environments.
As more farm and land management machinery becomes electrified, familiarizing yourself with the role of a battery management system in a tractor battery can help you understand what’s involved and why a good EV BMS is essential for getting the most out of your electric tractor.
Tractor Battery Basics
Electric machinery is powered by electricity, but for that machinery to have wireless functionality, it requires a battery. Like an EV passenger car, an EV tractor battery module typically consists of multiple lithium ion cells arranged in such a way that their energy can be charged or discharged simultaneously. But not all large format batteries are the same and their design, dimensions, and weight will vary across manufacturers.
The battery management system is another important differentiator. Manufacturers engineer their EV BMSs with their own features, paying attention to capabilities and specifications that are suitable to the battery type, intended use, and performance requirements of the machinery.
For a real-life manufacturer example, Monarch Tractor, maker of the world’s first 100% electric, driver-optional, and smart tractor on the market, has a lithium ion battery pack that has been tested and validated across many tough agricultural applications. That’s because farmers and land managers depend on implements like mowers, trailer bins, feed pushers, cultivators, weeders, and rotary tillers to reliably function in the inconsistent off-road environment where the tractor is working. Each of these implements and operations has their own demands on the battery. Monarch has developed a battery management system that supports safely powering the tractor for up to 14 hours depending on farm, implement, and operation to meet the needs of specialty farms and land managers.
What is a Battery Management System?
While the tractor battery is responsible for storing energy and discharging it to do work, that battery relies on a BMS (battery management system) to optimize its performance, safety, and longevity. It accomplishes this by monitoring and controlling various parameters and vital signs such as voltage, current, temperature, and state of charge. A BMS directly impacts a tractor battery’s safety, efficiency, and lifespan thus affecting overall maintenance costs and maximizing energy utilization.
A BMS is used in many devices — smartphones, laptops, drones, portable medical equipment, backup power equipment, and electric vehicles such as cars, e-bikes, and tractors. These types of devices and machinery use a battery that can be charged for reuse and the BMS regulates the battery’s energy output, ensuring adequate power is available to do work over a period of time without overloading the system and therefore protecting the technology and owner’s investment.
Battery monitoring systems vary among manufacturers with some being more advanced than others. For instance, Monarch’s BMS control system features an industry-leading thermal propagation performance. Thermal propagation performance refers to how well a battery system resists the spread of heat from one cell to another. If heat spreads too quickly and easily from a single source within the battery pack, such as a cell, to neighboring cells, it can potentially lead to a fire if not properly managed. Good thermal propagation performance is an important safety preventative.
Several factors can influence a battery’s thermal propagation performance including cell design, packing density, thermal insulation between cells, and materials used in the battery pack. Knowing your tractor battery has an advanced thermal propagation performance is an additional layer of safety and security in the performance of your battery-powered tractor.
Battery Management System vs. Battery Monitoring System
It’s not uncommon to conflate a battery management system with a battery monitoring system. A monitoring system is often part of a comprehensive BMS, but the two terms are not interchangeable. A battery monitoring system’s primary purpose is to measure and provide real-time battery data. It does not initiate actions based on the data it collects. That responsibility belongs to the BMS.
A battery management system uses data provided by the monitoring system to actively control the battery, making sure the cells function within their safe operational window, which includes an array of vitals such as temperature, voltage, and current. This helps keep the cells balanced, which is a preventative in cell decay.
What are the Benefits of an Electric Vehicle BMS?
An EV BMS, such as in a tractor, safeguards optimal battery performance. Through ongoing monitoring of voltage, temperature state of charge, and other data, a BMS protects the battery and machinery from potentially harmful conditions. It also reports the battery’s operational status to external devices and calculates the battery’s level of charge and displays it to the tractor operator. In a pedestrian example, if you’ve ever looked at your cell phone’s battery levels, you’ve taken advantage of one of the benefits of a BMS.
Key protective functions and benefits of a BMS includes:
- Preventing overcharging and over-discharging, which can damage battery cells and shorten their lifespan.
- Balancing cell voltages to ensure uniform charging and discharging.
- Improving overall battery performance and energy efficiency to extend battery life during each charge.
- Performing real-time monitoring and diagnostics, helping users make informed decisions on battery maintenance.
- Providing short-circuit protection, which prevents overheating and risk of fire.
- Monitoring temperature to prevent overheating and potential safety hazards.
- Shutting down of the battery system to prevent dangerous situations.
- Communicating data on battery status to other systems or users.
By carefully managing a battery’s vital signs, a BMS can also empower valuable functionalities beyond simply powering a machine. Being first to market with a tractor that is both electric and smart, Monarch Tractor has excelled in optimizing what a battery can do to bring even greater value to its electric tractor. In Monarch’s MK-V, additional benefits supported by the BMS include:
On-the-go Visibility
In addition to displaying the battery charge to the operator on the smart screen, farm managers and owners can log into Wingspan Ag Intelligence (WingspanAI) app while on-the-go and get real-time updates on battery health and charge. Fleet managers can monitor their MK-V’s health and error codes. WingspanAI identifies issues, provides diagnostics, and proposes countermeasures.
Flexible Horsepower
An advanced BMS supports the MK-V’s ability to deliver up to 70 horsepower, when needed. The MK-V delivers 40 HP at the PTO continuously and the additional 30 HP is available when the tractor needs it for the drive and hydraulic systems. Each system adapts and draws what it needs, accurately adjusting to fluctuating demands stemming from the implement used and operational requirements. By delivering 70 HP only when it’s needed, the battery runtime is extended. Requiring a consistently higher HP does shorten the runtime, though farmers have reported the impact has not been enough to negatively affect their workday.
Exportable Power
Monarch’s BMS also allows the MK-V to function as a portable power wall, bringing exportable power to remote places on a farm or property, or providing backup power when the grid is down. Three outlets, a 12v, 110v, and 220v are built into the MK-V giving farmers and land managers a reliable source of power. If a tractor owner’s energy provider utilizes a dynamic rate system, the owner can charge the tractor when the rates are lowest, typically at night, then use that lower-cost energy to power operations during the day.
Empowered Operations
As electric tractors continue to bring profitability and sustainability to agriculture and land management, the BMS, battery management system, plays an unseen, but important component in ensuring their efficiency, safety, and longevity. By optimizing battery performance, monitoring vital parameters, and providing real-time data across smart devices such as Monarch has done, the BMS enhances the battery-powered tractor's operational capabilities allowing owners to accomplish more with their EV machinery than ever before. As we push towards a cleaner, safer, and more profitable future in land management and farming, electric tractors like the groundbreaking MK-V and its advanced BMS is powering the movement efficiently and effectively.
