Custom Battery Pack Manufacturer for 18650 & 21700 Lithium-ion Packs
Larnek Power engineers custom lithium-ion battery packs around your equipment — cell selection, pack design, BMS integration and supply, from the first prototype through repeat production orders.
About us
A Battery Pack Manufacturer Focused on Cylindrical Cells
Larnek Power focuses on lithium-ion cells such as 18650 and 21700, giving us deep experience in the key details that influence battery pack performance in your equipment — including cell grade, series-parallel configuration, welding quality, BMS matching, and thermal management considerations.
As a custom battery manufacturer, we typically begin with the requirements of your equipment rather than a fixed catalogue specification. Voltage, runtime, available space and operating conditions help define the direction of the pack design, which is then developed around the needs of the application
Battery Packs Built on 18650 and 21700 Cells
18650 Battery Packs
Compact packs for portable instruments, lighting and handheld equipment, with flexible series-parallel layouts.
21700 Battery Packs
More capacity and current per cell, for longer runtime and higher-load equipment in a similar footprint.
Industrial Battery Packs
Packs designed around equipment integration, demanding duty cycles and long-term repeat supply.
Custom Battery Manufacturing Around Your Device
Unlike custom lithium battery manufacturers that start from a standard catalogue, we define each pack from your device’s electrical, mechanical and environmental limits.
Voltage and capacity
Series-parallel configuration matched to your load and required runtime.
Connectors and wiring
Connector type, pinout and cable length built to your drawing.
Size and shape
Cell layout fitted to the space your device actually has, not a standard box.
Enclosure and insulation
Heat-shrink, insulation barriers, brackets or housings.
Charge and discharge current
Cell grade and conductor sizing for both continuous and peak load.
Temperature range
Operating limits and heat paths reviewed against your real duty cycle.
BMS and protection
Over-charge, over-discharge, over-current, short-circuit and temperature protection.
Labels and documents
Rating labels, batch traceability and a pack datasheet you can file.
Equipment We Build Battery Packs For
We work as one of the battery pack suppliers for industrial devices and professional equipment, where runtime, fit and reliability matter more than a shelf price.
Industrial equipment
Packs that survive a full shift and fit the machine as built.
Cleaning equipment
Lithium replacements for lead-acid in scrubbers and sweepers.
Portable instruments
Compact packs with stable voltage and low self-discharge.
Inspection and measurement
Steady output so readings stay repeatable through the charge.
Communication equipment
High pulse current for transmit bursts without voltage sag.
Remote monitoring
Long standby life in units nobody wants to visit twice a year.
Emergency lighting
Packs specified for standby duty and the paperwork that comes with it.
Portable power equipment
Higher-current packs where weight and runtime both matter.
working with us
Why OEM Teams Choose Larnek Among Custom Battery Suppliers
Specialised focus
Two cell formats, worked on every day. We build only with 18650 and 21700 cylindrical cells, so we know how different cell grades perform under load, heat and vibration, and can recommend the right cell for your runtime, size and budget.
Engineering-led design
Your device sets the specification, not a catalogue. We start from your voltage, current, space and operating environment, then define the cell configuration, BMS protection, wiring and enclosure to match, with drawings you can review before anything is built.
Prototype to production
One partner across the whole project, not a handoff. The team that specifies your first samples carries the project through pilot runs and volume production, so the design you approved is the design you receive, with no re-engineering between stages.
Quality and compliance
Test reports and shipping papers planned from day one. Packs go through incoming cell checks, in-process inspection and final electrical testing, and we prepare the documents export requires, such as UN38.3 test summaries and safety data sheets, alongside your project.
Long-term supply
Same cells and same build on every repeat order. Once your design is approved, we lock the cell model, BMS and build specification, and notify you in advance if a component ever needs to change, so every batch matches the first.
Cost-effective supply
We offer highly competitive prices without compromising on quality. Thanks to long-standing, solid partnerships with battery cell suppliers in Shenzhen and our own manufacturing facilities, we can effectively reduce your procurement costs while ensuring that cell quality, battery pack design, and manufacturing consistency remain uncompromised.
Engineering, Production and Quality Control
Larnek Power operates its own factory and production lines, giving us direct control over the key stages of battery pack manufacturing. From engineering specifications through assembly and final inspection, we take responsibility for how each pack is built and verified.
Checks during the build:
• Incoming cell inspection against the approved datasheet
• Capacity, voltage and internal resistance matching before assembly
• Weld inspection during pack assembly
• BMS function testing
• Finished-pack electrical testing
Documents we can provide:
• UN38.3 test report
• Safety Data Sheet (SDS / MSDS)
• IEC 62133 testing arranged per project
• UN3480 / UN3481 packaging and labelling support
From Requirements to Volume Production
Each step has something you receive, so you always know where the project stands.
Requirement review
You send specs and drawings. We reply with feasibility notes and open questions.
Cell selection
Cell options with datasheets, and the trade-offs between them stated plainly.
Electrical and mechanical design
Pack configuration, a layout drawing and a draft bill of materials.
BMS integration
Protection parameters and a BMS specification sent for your approval.
Prototyping
Samples to test for fit and function in your own device.
Testing and validation
Our test report, your field feedback, and design changes where needed.
Volume production
Inspection records and shipping documents.
Trusted by Engineers & OEMs Worldwide
Questions buyers ask first
Your Battery Pack, Built Safe, Compliant and On Time
Backed by a strong Shenzhen supply chain, a dedicated engineering team and hands-on export experience, Larnek Power helps OEM teams move custom battery packs into production with consistent quality, competitive cost and the paperwork export requires.
Tell Us About Your Battery Project
Larnek Power supports OEM and industrial customers with custom 18650 and 21700 lithium-ion battery packs, from initial requirements and prototyping through volume production.
Tell us about your application, target voltage and capacity, size limits, current requirements, estimated quantity, and any drawings or existing battery details. Our engineering team will review your requirements and help define the next steps for your project.