Start by defining the battery’s role in the final product and its main operating requirements. Provide the nominal voltage, required runtime, continuous and peak current, available battery space, charging method, operating temperature, destination market, and expected order quantity.

VTCBATT engineers use this information to select the battery chemistry, cell model, series-parallel configuration, BMS rating, enclosure, wiring, connector, and charging solution.

Product drawings, battery-compartment dimensions, equipment photos, and load data are also helpful. For equipment with motors, pumps, heaters, or wireless transmitters, please specify the peak current and how long it lasts. Average power consumption alone may not be enough to size the cells and BMS correctly.

Clear application and load information helps us design a custom battery that fits the product, provides the required runtime, and performs reliably under actual operating conditions.

Voltage and capacity alone are not enough for an accurate custom lithium battery design and quotation. Engineers need additional information about the electrical requirements, physical constraints, operating environment, and application conditions.

Electrical Requirements

• Nominal voltage and required capacity
• Continuous discharge current
• Peak current and peak duration
• Required runtime
• Charging voltage, charging current, and charging method
• Required BMS functions, protection features, and communication requirements

Mechanical Requirements

• Maximum battery dimensions and weight limitations
• Battery enclosure type and material
• Connector type, wire length, wire gauge, and terminal requirements
• Installation method and mounting requirements
• IP rating requirements

Environmental Requirements

• Operating and storage temperature range
• Indoor or outdoor application conditions
• Vibration, moisture, dust, or other environmental requirements

Compliance Requirements

• Destination market
• Required certifications and documentation

Application Requirements

For vehicles and industrial equipment, please provide additional details such as motor power, controller model, load conditions, terrain, duty cycle, and expected runtime.

Prototype quantity, estimated annual volume, and production schedule also help us prepare a more accurate quotation.

Complete application information helps engineers select suitable cells, size the BMS correctly, and develop a battery solution that performs reliably in the actual operating environment.

For a custom lithium battery project, the right chemistry depends on the application requirements, including safety, energy density, cycle life, discharge current, operating temperature, available space, and expected service life. No single lithium battery chemistry is suitable for every application.

As a custom lithium battery manufacturer, VTCBATT commonly designs custom lithium battery solutions using the following chemistries:

Custom Lithium Polymer Battery

Typical applications: Wearables, IoT devices, slim electronics, medical devices, and products with limited or irregular battery space.

Lithium polymer pouch cells provide more flexibility in battery thickness, width, length, and shape, making them suitable for compact custom designs.

Custom NMC Lithium-ion Battery

Typical applications: Portable equipment, robotics, medical devices, power tools, electric mobility, and high-drain equipment.

NMC lithium-ion batteries are suitable when products require higher energy density and compact size. Thermal management and BMS protection should be carefully considered during battery design.

Custom LiFePO4 Battery

Typical applications: Energy storage systems, golf carts, RVs, marine batteries, industrial vehicles, backup power, and deep-cycle applications.

LiFePO4 is recommended when safety, thermal stability, and long cycle life are more important than maximum energy density.

Custom Li-SOCl2 Primary Lithium Battery

Typical applications: Smart meters, remote monitoring, tracking devices, security equipment, and industrial IoT.

Li-SOCl2 is used for long-life, low-current applications requiring low self-discharge and extended standby time.

Custom Li-MnO2 Primary Lithium Battery

Typical applications: Sensors, alarms, memory backup, medical sensors, and compact electronic devices.

Li-MnO2 is suitable for primary battery applications requiring stable voltage output, long shelf life, and reliable pulse performance.

The final battery chemistry selection should be based on the actual load profile and operating conditions. A higher energy density battery is not always the best choice if the application requires longer cycle life, higher pulse current, wider temperature operation, or better thermal stability.

Yes. As a custom lithium battery manufacturer, VTCBATT can customize lithium battery voltage, capacity, dimensions, shape, connector position, wiring, and enclosure according to the equipment requirements and available installation space.

Battery voltage
Voltage is determined mainly by the cell chemistry and series configuration. Common custom battery voltages include 3.7V, 7.4V, 11.1V, 12V, 24V, 36V, 48V, 60V, and 72V. The final design must match the equipment input range, controller, inverter, charger, and power management system.

Battery capacity
Capacity is adjusted through cell selection and parallel configuration. Engineers calculate the required Ah or Wh based on runtime, continuous and peak current, discharge depth, operating temperature, available space, weight limit, charging time, and expected cycle life. A larger capacity is not always practical if the product has strict size or weight limits.

Battery size
The pack can be designed around the maximum available length, width, and height. Product drawings, 3D files, battery-compartment dimensions, and equipment photos help confirm installation clearance, wire outlets, connector locations, mounting points, and service access.

Battery shape
Lithium polymer pouch cells provide greater flexibility for thin, compact, or irregular battery spaces. Cylindrical and prismatic cells can also be arranged in different layouts using cell holders, insulation, busbars, support structures, and custom enclosures.

Before tooling or mass production, the voltage, capacity, dimensions, cell layout, connector, wiring, and enclosure should be verified through drawings and prototype testing. This helps confirm that the battery fits the product and performs correctly under the actual load.

Yes. VTCBATT can customize wires, connectors, terminals, output direction, mounting methods, and enclosure designs for custom lithium battery packs based on electrical requirements, mechanical constraints, and operating conditions.

Battery wires

Battery wires can be customized by wire gauge, length, insulation material, color, output direction, and harness structure. Wire selection depends on continuous current, peak current, cable length, temperature rise, and installation conditions. For high-current battery packs, undersized wires can cause excessive voltage drop, heat generation, and reduced reliability.

Battery connectors

Connectors are selected according to the equipment interface, current rating, installation space, plugging frequency, and environmental requirements. Common options include JST, Molex, Anderson, XT series, aviation connectors, waterproof connectors, and customer-specified connectors. 

For smart battery packs, connectors can also include communication and sensing pins for functions such as CAN, RS485, SMBus, UART, NTC, or identification signals.

Battery terminals

Terminal design depends on output current, pack structure, mounting method, and maintenance requirements. VTCBATT supports ring terminals, threaded terminals, nickel tabs, busbar terminals, quick-connect terminals, and customized terminal locations.

The design should consider polarity protection, contact resistance, vibration, mechanical strength, and service accessibility.

Battery enclosures

Battery enclosures can be designed with heat-shrink film, ABS plastic, flame-retardant plastic, sheet metal, aluminum, or other suitable materials. The enclosure design depends on battery size, cell layout, impact resistance, vibration, moisture protection, heat dissipation, installation method, and required IP rating.

For outdoor, marine, vehicle, or industrial applications, the enclosure should be designed around the actual installation environment, including sealing method, waterproof connector selection, cable gland position, pressure relief (if required), drainage, corrosion protection, vibration resistance, and mounting strength.

The final wire, connector, terminal, and enclosure design should be verified through drawings, samples, and prototype testing. This helps confirm mechanical fit, electrical performance, and long-term reliability before mass production. 

Yes. VTCBATT can configure existing BMS platforms or develop project-specific BMS solutions for custom lithium battery packs requiring specific protection logic, monitoring, communication, balancing, or high-power switching demand. 

The BMS design is based on the cell chemistry, pack voltage, series configuration, continuous and peak current, charging method, operating temperature, communication requirements, and actual equipment load. A BMS should be designed as part of the complete battery system, not treated as an independent component.

BMS protection functions

Depending on the application, the BMS can provide:

• Cell overcharge and over-discharge protection
• Charge and discharge overcurrent protection
• Short-circuit protection
• Charge and discharge temperature protection
• Low-temperature charging cutoff
• Cell voltage monitoring
• Cell balancing
• Sensor, communication, and system fault reporting

Protection thresholds must match the cell specification and operating conditions. Incorrect settings may cause unnecessary shutdowns or insufficient protection.

Cell balancing

Cell balancing reduces voltage differences between series-connected cell groups. Passive balancing is commonly used because it is simple, reliable, and cost-effective.

Active balancing may be considered for large-capacity or high-series-count packs when faster balancing, improved energy utilization, and additional system cost are justified.

Balancing cannot compensate for poorly matched, aged, or damaged cells. Cell matching, production consistency, and thermal uniformity remain important before BMS installation.

Fuel gauge and battery monitoring

For smart battery packs, the BMS can monitor and report:

• State of charge (SOC)
• State of health (SOH)
• Remaining capacity
• Pack and individual cell voltage
• Charge and discharge current
• Battery temperature
• Cycle count
• Warning and fault status

Accurate SOC estimation requires more than voltage measurement. The BMS may consider current measurement, voltage monitoring, temperature compensation, battery aging, and actual charge-discharge conditions.

Communication and system integration

The BMS can support CAN, RS485, SMBus, UART, Bluetooth, or project-specific communication protocols.

For protocol development, customers should provide the communication protocol document, CAN matrix or register table, baud rate, message timing, connector pin definition, required data fields, and fault-handling requirements.

Communication must be verified with the actual charger, controller, inverter, display, or host device because matching wiring alone does not guarantee compatibility.

High-power BMS architecture

For high-power applications such as golf carts, industrial vehicles, ESS, and robotics, BMS design requires additional current and thermal analysis.

The architecture and current rating depend on:

• Pack voltage
• Continuous and peak current
• Peak-current duration
• Startup or inrush current
• Regenerative charging current
• Short-circuit energy
• Cooling conditions
• Cable and connector ratings
• Duty cycle
• Ambient temperature

The BMS current rating should not be selected only from the motor or equipment nameplate.

Prototype verification

Before mass production, the BMS should be tested with the actual battery pack and equipment. Testing normally includes protection functions, charge and discharge behavior, temperature response, balancing, communication, fault recovery, repeated peak loads, and charger compatibility.

This system-level verification confirms that the cells, BMS, wiring, connectors, charger, controller, and host equipment work together correctly. The final BMS should include the functions required by the application without unnecessary complexity or cost.

Yes. VTCBATT can integrate CAN, RS485, SMBus, UART, Bluetooth, and customer-specific communication protocols into custom lithium battery packs when the equipment requires battery monitoring, data exchange, fault reporting, or system control.

Not every battery pack requires communication. The interface should be selected according to the requirements of the charger, inverter, motor controller, display, or host control system.

Communication protocols supported

Depending on the project, the battery BMS can support:

* CAN communication

* RS485 communication

* SMBus

* UART

* Bluetooth monitoring

* Customer-specific communication protocols

Battery data available

Typical battery information transmitted through the communication interface may include:

* Pack voltage

* Individual cell voltage

* Charge and discharge current

* Battery temperature

* State of charge (SOC)

* State of health (SOH)

* Remaining capacity

* Cycle count

* Warning messages

* Fault status

* Protection events

Protocol integration requirements

Before development, customers should provide the communication protocol document, CAN matrix or register table, baud rate, message timing, connector pin definition, required data fields, and fault-handling requirements.

The communication interface should be verified together with the actual charger, controller, inverter, display, or host system. Matching the connector and wiring alone does not guarantee protocol compatibility, so communication functions should be tested before mass production.

Prototype verification helps confirm that the battery, BMS, communication system, and equipment controller operate correctly together. 

Yes. VTCBATT can design custom lithium battery packs for low-temperature, high-temperature, outdoor, marine, vehicle, and industrial environments. The operating conditions should be clearly defined before engineers select the cells, design the BMS, and confirm the battery structure.

Low-temperature lithium battery design

For low-temperature applications, engineers need to confirm the minimum discharge temperature, minimum charging temperature, storage temperature, current load, and required runtime.

The battery design may include low-temperature cells, low-temperature charging cutoff, insulation materials, battery heating elements or heating pads, temperature sensors, or BMS-controlled heating logic. Charging lithium batteries below the permitted temperature can damage the cells, so low-temperature charging protection is especially important.

High-temperature lithium battery design

For high-temperature applications, the design should consider cell chemistry, continuous current, peak current, enclosure material, thermal management, BMS temperature limits, heat dissipation, and installation location.

High temperature can accelerate cell aging and reduce cycle life. If the battery is installed near motors, controllers, engines, inverters, or inside sealed metal compartments, engineers should evaluate the actual battery enclosure temperature rather than only the ambient temperature.

Water-resistant and waterproof battery design

For water-resistant or waterproof battery packs, the enclosure design may include sealing structures, gaskets, waterproof connectors, cable glands, potting compounds, protective coatings, drainage paths, corrosion-resistant materials, and pressure relief if required.

The required IP rating should be selected based on the actual operating environment, including splash, rain, temporary immersion, cleaning methods, water pressure, installation direction, cable outlet position, and maintenance requirements.

Environmental verification

An IP rating alone does not confirm suitability for salt spray, condensation, pressure washing, vibration, thermal cycling, or long-term outdoor exposure. These conditions should be reviewed separately during the battery design process.

Before mass production, prototype testing with the actual equipment or installation environment should be performed whenever possible. This helps verify sealing performance, temperature protection, thermal behavior, connector durability, and long-term safety.

The development time for a custom lithium battery depends on the level of engineering involved and the degree of customization required.

Simple projects using existing cells, an existing BMS platform, and a standard enclosure can move faster. Projects involving custom structures, communication, firmware development, molds, waterproof design, low-temperature solutions, or certification testing usually require additional engineering time.

Typical custom lithium battery development timeline:

• Battery solution proposal: 3 to 7 days
• Design confirmation and engineering review: depends on project complexity and customer feedback
• Prototype sample production: about 2 to 3 weeks
• Prototype testing and customer evaluation: depends on equipment testing requirements
• Pilot production: about 3 to 5 weeks after prototype approval
• Mass production: after prototype validation, specification approval, and production preparation 

The actual schedule may also be affected by material availability, BMS complexity, enclosure design, communication requirements, testing scope, and the customer approval process.

A custom battery project is not determined by manufacturing speed alone. Design changes, material lead time, testing results, and approval cycles are common factors that affect the final schedule.

To shorten the development cycle, customers should provide complete requirements at the beginning, including electrical requirements, mechanical dimensions, environmental conditions, charger information, communication requirements, application details, and estimated order quantity. 

Yes. VTCBATT can provide custom lithium battery prototype samples before mass production. Prototype production normally takes about 2 to 3 weeks after the technical specifications and sample requirements are confirmed.

Prototype testing checks whether the battery meets the electrical, mechanical, thermal, and system-integration requirements, including:

• Battery fit and installation
• Voltage and capacity
• Continuous and peak current performance
• Charger compatibility
• BMS protection functions
• Communication with the equipment or host system
• Temperature performance
• Mechanical structure, enclosure, connector, cable arrangement, and labeling requirements

For simple projects using existing cells, an existing BMS platform, and a standard enclosure, prototype production can usually move faster. Projects requiring custom PCB design, firmware development, communication protocol integration, new tooling, waterproof structures, heating functions, or special testing may require additional time.

Some projects may require more than one prototype round. The first sample may verify electrical performance and basic mechanical fit, while later samples may confirm the final enclosure, mounting structure, firmware, production materials, and packaging requirements.

VTCBATT recommends completing equipment-level testing before approving pilot production or mass production. A battery that passes laboratory testing may still require adjustment when connected to the actual controller, motor, inverter, charger, display, or host system.

After prototype approval, the project can move to pilot production. Pilot production confirms assembly processes, testing methods, quality control points, packaging requirements, and production consistency before mass production.

The required tests and certifications for a custom lithium battery depend on the battery chemistry, voltage, capacity, application, transportation method, destination market, and customer requirements.

Not every battery pack requires the same certification or testing program. The correct testing scope should be confirmed during the design stage because certification requirements can affect battery structure, BMS selection, materials, cost, and development schedule.

Battery Safety and Protection Testing

Safety testing verifies that the battery pack, cells, and BMS can operate safely under normal and abnormal conditions.

Depending on the application, testing may include:

• Overcharge protection testing
• Over-discharge protection testing
• Charge and discharge overcurrent protection testing
• Short-circuit protection testing
• Charge and discharge temperature protection testing
• Low-temperature charging cutoff verification
• Insulation resistance testing
• Dielectric withstand testing, if required
• BMS fault response testing
• Thermal protection and abnormal heating inspection

The purpose of these tests is to confirm that the battery protection system responds correctly and prevents unsafe operating conditions.

Battery Performance and Engineering Validation

Performance testing verifies whether the custom lithium battery pack meets the actual equipment requirements.

Depending on the project, testing may include:

• Cell voltage, capacity, and internal resistance matching
• Battery capacity verification
• Charge and discharge curve testing
• Continuous and peak current testing
• Cycle-life and aging testing
• Temperature performance testing
• Charger compatibility testing
• Communication testing with CAN, RS485, SMBus, UART, or Bluetooth
• Vibration and mechanical structure testing
• Waterproof or IP-related testing, if required
• Final dimension, appearance, label, and packaging inspection

For vehicle, industrial, and energy storage applications, testing should be performed according to the actual operating conditions rather than only laboratory specifications.

Production Quality Control and Traceability

For mass-production battery packs, VTCBATT performs quality inspections throughout the manufacturing process to ensure battery consistency, safety, and production reliability.

Quality control activities may include:

• Incoming cell inspection
• Cell matching and grouping
• BMS functional testing
• Capacity testing
• Aging inspection
• Insulation, wiring, and connector polarity inspection
• Final appearance inspection
• Shipment inspection

When required by the project, key production information such as cell batches, BMS versions, production records, and test results can be traced during manufacturing.

Common Battery Documents 

Depending on the battery application, destination market, transportation method, and customer requirements, VTCBATT can provide relevant battery documents and compliance records, including:

• UN38.3 test report 
• MSDS (Material Safety Data Sheet)
• Battery performance or safety test reports
• Product specifications
• Transportation documents for air, sea, or land shipment
• RoHS and REACH compliance documents, if required

These documents may be required for customer approval, shipping, customs clearance, and regulatory review.

UN38.3 is a transportation safety requirement for lithium batteries. It confirms that the battery has passed required transportation tests, but it does not replace product safety standards such as IEC 62133, UL 2054, UL 1973, or other application-specific certifications.

Certification Requirements by Destination Market

Certification requirements depend on the product category, battery type, application, and destination country.

United States and North America

Depending on the application, relevant standards may include:

• UL 1642
• UL 2054
• UL 1973
• UL 2580
• UL 2271, if applicable
• FCC or related EMC testing, if the battery pack includes wireless communication or electronic control functions

Requirements vary between consumer products, energy storage systems, industrial equipment, and electric vehicles.

European Union

Depending on the product category and battery type, requirements may include:

• CE
• RoHS
• REACH
• EMC testing
• Low Voltage Directive, if applicable
• EU Battery Regulation (Regulation (EU) 2023/1542)
• IEC/EN 62133
• IEC/EN 62619, if applicable for industrial lithium battery applications

International Safety Standards

Common international standards include:

• IEC 62133 for portable rechargeable lithium batteries
• IEC 62619 for industrial lithium battery applications
• CB certification based on IEC standards for international market access

Japan

Depending on the battery pack, charger, and product category:

• PSE certification may be required.

South Korea

Depending on the battery product and application:

• KC certification may be required.

India

Depending on the battery type and regulatory scope:

• BIS certification may be required.

China

Depending on the battery type and final product category, requirements may include:

• GB standards related to lithium battery safety and performance
• CQC certification
• CCC certification, if applicable

Thailand

TISI certification may apply depending on the battery type and final product category.

Important Note About Battery Certifications

A custom lithium battery does not automatically require every available certification.

The required standards depend on:

• Battery chemistry
• Voltage and capacity
• Application
• Product category
• Destination market
• Transportation method
• Customer approval requirements

Certification requirements should be confirmed before prototype development because they may affect:

• Battery design
• Material selection
• Sample quantity
• Testing cost
• Project timeline

VTCBATT recommends confirming certification requirements at the beginning of a project to avoid design changes during prototype or mass production.

For more information about battery compliance and certification planning, see our Battery Certification Guide.

A reliable custom lithium battery manufacturer should do more than provide a voltage, capacity, and price. The supplier should be able to explain why the selected cell, BMS, enclosure, connector, charger, and testing plan are suitable for the actual equipment requirements.

When choosing a custom lithium battery manufacturer, buyers should evaluate five key areas:

Engineering capability

The manufacturer should understand the complete application requirements, including voltage, capacity, continuous current, peak current, operating temperature, battery space, charger compatibility, communication requirements, and expected production volume.

The engineering team should be able to explain the cell chemistry, series-parallel configuration, BMS rating, thermal design, enclosure structure, wiring, connector selection, and validation plan.

Application experience

Choose a manufacturer with experience in applications similar to your product. IoT devices, medical equipment, energy storage systems, industrial vehicles, robotics, RVs, marine equipment, and electric mobility products may require different battery designs.

Relevant project experience helps identify risks such as startup current demand, charger incompatibility, communication mismatch, vibration, heat buildup, waterproof sealing, and installation limitations before mass production.

Production quality and traceability

A reliable manufacturer should have controlled production processes, including cell batch traceability, cell matching, BMS functional testing, capacity verification, aging inspection, final inspection, and shipment inspection.

For custom lithium battery projects, prototype performance must be repeatable during mass production.

Certification and documentation support

The manufacturer should understand transportation documents, safety standards, destination-market requirements, and customer approval documents. Certification planning should be discussed before prototype development because it may affect battery design, material selection, sample quantity, cost, and schedule.

Long-term technical support

A reliable supplier should provide support after delivery, including failure analysis, charge and discharge data review, BMS fault record analysis, warranty support, and design improvement when required.

VTCBATT provides custom lithium battery solutions for industrial equipment, energy storage systems, vehicles, IoT devices, medical products, security systems, and other applications. For OEM and ODM projects, some customer information cannot be disclosed due to confidentiality agreements, but VTCBATT can explain its engineering process, testing methods, manufacturing capabilities, and application experience based on project requirements.

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