Battery charging cycles: How to maximise the service life of your e-fleet and reduce TCO
The number of charging cycles is a decisive lever for managing the total cost of ownership (TCO) of your e-fleet. Incorrect charging behaviour can significantly shorten the service life of a 110 kWh battery. Understand the key factors and safeguard the residual value of your vehicles.
The topic briefly and concisely
A charging cycle is the use of 100% of the battery capacity, often made up of several partial charges, not a single charging process.
A charging window between 20% and 80% SoC protects the battery and can significantly extend its service life compared with constantly charging to full.
HEERO eDrive systems with 110 kWh or 137 kWh batteries and intelligent BMS are designed for maximum charging cycles and minimum TCO for fleets.
For fleet operators, battery service life is a key economic factor. Every charging cycle affects degradation and thus directly the Total Cost of Ownership (TCO). Modern lithium-ion batteries are designed for 1,000 to 3,000 charging cycles, which enables a high mileage. However, this potential can only be fully exploited through an optimized charging strategy and an intelligent battery management system (BMS). This article shows you how to maximize the number of usable charging cycles of your battery, reduce operating costs and secure the operational readiness of your fleet in the long term.
Understanding the fundamentals of charging cycles and interpreting them correctly
A charge cycle does not correspond to a single charging process, but to the complete discharging and recharging of 100% of the battery capacity. This process can consist of several partial charges. For example, if you charge the 110 kWh battery of a HEERO e-transporter twice from 30% to 80%, this corresponds to one full charge cycle in total (2 x 50% = 100%). This definition is crucial for understanding the manufacturer's specifications regarding service life. Modern batteries in commercial vehicles typically achieve 1,000 to 3,000 charge cycles before their capacity drops below 80%. A clear understanding of the State of Charge (SoC) is therefore the basis for any optimization. The type of use significantly determines how quickly these cycles are reached.
Cyclic vs calendar ageing: the two drivers of degradation
Battery aging is determined by two primary processes that run in parallel. Cyclic aging is caused by use, i.e. the charging and discharging of the battery cells. Each charging cycle causes minimal physical and chemical changes that accumulate over thousands of cycles. Calendar aging, on the other hand, takes place independently of use and is influenced by time, temperature, and state of charge (SoC). Storage at 30 °C can already double calendar aging compared to 20 °C. Likewise, permanently high or very low states of charge of over 80% or below 20% accelerate chemical degradation. For fleet managers, it is important to consider both types of aging in order to maintain the state of health of the battery (SoH) over the long term. These factors are crucial for the residual value forecast of your vehicles.
Implement charging strategies to maximise the number of cycles
By adjusting charging strategies, the usable number of battery cycles can be significantly increased. The most important rule is to avoid extreme states of charge in daily operations. A charging window between 20% and 80% SoC has proven to be optimal and can extend the lifespan of the cells by years. Full charges to 100% should only be carried out before long-distance journeys, with the vehicle being moved promptly afterwards. In addition, the charging speed plays a role. Frequent DC fast charging at high power subjects the battery to greater thermal and chemical stress than slow AC charging in the depot. A study showed noticeably higher degradation after 200,000 km in vehicles with a high proportion of fast charging. An intelligent mix of depot and fast charging is the key.
Optimize charging window: Keep the state of charge between 20% and 80% during regular operation.
Plan full charges: Only charge to 100% when necessary, ideally directly before starting a journey.
Prioritize AC charging: Use gentle depot charging overnight as standard.
Use DC charging intelligently: Use fast chargers specifically on long routes, not in daily operation.
Manage temperatures: Park vehicles in the shade in summer and use pre-conditioning.
These measures reduce stress on the battery cells and maximize their lifespan.
The role of the battery management system (BMS) in long-term durability
A modern battery management system (BMS) is the brain of the battery and crucial for its protection and longevity. It continuously monitors the voltage, current and temperature of each individual cell. The BMS prevents critical conditions such as deep discharge, overcharging and overheating, which would lead to irreversible damage. A key function is “cell balancing”, in which the HEERO BMS actively equalises the charge states of the individual cells. Without this balancing, small differences between the cells would be amplified over the charging cycles and prematurely reduce the battery’s total capacity. HEERO relies on a robust BMS in its self-developed eDrive System, which is specifically designed for the high demands of commercial use. It optimises every charging process for maximum efficiency and minimal degradation. This secures your investment in fleet electrification in the long term.
Economic impact of charging cycles on TCO
Optimizing charging cycles has direct financial benefits and lowers the Total Cost of Ownership (TCO) of your fleet. A longer battery life means later and less frequent replacement, which is one of the most expensive components of an electric vehicle. This significantly reduces maintenance and repair costs over the retention period. In addition, a good State of Health (SoH) of the battery ensures a higher residual value of the vehicle, which has a positive effect on leasing rates and resale value. Fleet managers can significantly reduce operating costs through data-driven charging management. Analyzing the charging times and costs is an important step in this process.
Reduced replacement investments: A maximized number of cycles postpones the time of an expensive battery replacement by years.
Lower operating costs: Gentle charging reduces energy consumption through higher efficiency and less cooling requirement.
Higher residual value: Vehicles with a proven good battery condition achieve prices on the used market that are significantly higher.
Maximum availability: Healthy batteries ensure the daily operational readiness and range of the vehicles.
A well-thought-out charging strategy is therefore not a technical detail, but a central instrument for cost control.
HEERO's approach: ensuring longevity through integrated, holistic development
HEERO addresses the challenge of battery life with a holistic approach from its in-house R&D Excellence Center in Munich. At the centre are generously dimensioned batteries designed for the demanding cycles of commercial use. Thanks to their high capacity, only small charging top-ups are often needed in everyday use, which significantly reduces cyclic ageing. Our eDrive system for every type of Mercedes-Benz Sprinter (model 907) is completed within a maximum of 10 working days and, in the case of D2E conversions (Diesel-to-Electric), even preserves valuable specialist bodywork. The intelligent HEERO battery management system ensures optimal thermal management and precise cell balancing, maximising service life. We focus on the TCO benefits and the rapid fulfilment of the Clean Vehicles Directive (CVD), by providing a durable and economical solution for your existing fleet. This safeguards the residual value of your vehicles and sustainably reduces operating costs.
FAQ
How many charging cycles does a modern commercial vehicle battery last?
Modern lithium-ion batteries in commercial vehicles are typically designed for 1,000 to 3,000 full charging cycles. At a range of 400 km per cycle, this corresponds to a theoretical total mileage of 400,000 to over 1,200,000 km before the capacity falls below 80% of the original value.
Does daily rapid charging shorten the battery's lifespan?
Yes, frequent and exclusive rapid charging (DC) can accelerate battery ageing. The high currents and the heat generated place greater strain on cell chemistry than slower AC charging. For maximum service life, it is advisable to use rapid charging selectively for long-distance journeys and to prefer gentle depot charging in everyday use.
What is the difference between gross and net battery capacity?
Gross capacity is the total amount of energy physically installed. Net capacity is the portion that can actually be used. Manufacturers reserve a buffer (typically 5–10%) to protect the battery from harmful deep discharge and overcharging. This buffer is managed by the BMS and makes a significant contribution to service life.
Does the outside temperature affect the number of charging cycles?
Temperature primarily affects calendar ageing and charging efficiency, not the number of cycles directly. Extreme heat (above 30 °C) permanently accelerates chemical ageing. Severe cold temporarily reduces available power and increases charging time. Good thermal management, as used by HEERO, is therefore crucial.
What warranty does HEERO offer for the battery?
HEERO offers comprehensive warranty coverage for the components installed in all HEERO eDrive systems, including the battery system. The exact terms are designed for demanding use in commercial fleets and provide long-term protection for your investment. Contact us for a detailed fleet analysis and specific warranty details.
Can I check my battery's condition myself?
The exact battery condition (State of Health, SoH) can only be read accurately using specialist diagnostic equipment. The vehicle display shows the state of charge (State of Charge, SoC). For a professional assessment, for example as part of fleet management or before a sale, specialist providers such as the Flying HEEROs offer a detailed analysis.
More useful links
Fraunhofer ISI offers a fact check and policy recommendations regarding batteries in electric cars in this policy brief.
The P3 Group provides a whitepaper on the topic of State of Health (SoH) of batteries.
The NOW GmbH offers an overview of studies on the total cost of ownership (TCO) of climate-friendly commercial vehicles.
The Bundesministerium für Verkehr und digitale Infrastruktur (BMV) presents a sub-study on fuel cell trucks as part of scientific investigations.
The VDE provides data for download relating to climate-friendly commercial vehicles.
The Bundesamt für Logistik und Mobilität (BALM) provides information on the funding program Climate Protection and Mobility (KSNI).
The Umweltbundesamt offers comprehensive information on climate protection in transport on its topic page.
