WORK
Quick answer: CMX Battery designs and manufactures custom lithium battery packs: lithium-ion and lithium-polymer packs for portable and industrial equipment, LiFePO4 packs for energy storage and traction, and complete systems with matched BMS and charger. Engineering samples typically ship three to five weeks after design freeze, with production following sample approval.
What we build
Our project work runs across three families. Portable packs — power tool replacements, medical devices, POS terminals and instrumentation — where the constraint is usually size and connector fit. Energy storage packs — home, commercial and containerised — where the constraint is cycle life and certification. And traction packs — forklift, golf cart, marine and RV — where the constraint is peak current and the physical envelope of the vehicle.
Across all three, the same engineering sequence applies: define the duty cycle in energy and peak power, lock the mechanical envelope, choose the chemistry the constraints point to, then configure the BMS as the interface to the host device.
| Pack family | Typical chemistry | What drives the design | Where it goes |
|---|---|---|---|
| Portable / tool packs | Li-ion 18650/21700, Li-polymer | Size, connector fit, cycle life at partial discharge | Power tools, medical devices, POS terminals, instrumentation |
| Energy storage packs | LiFePO4 (LFP) | Cycle life, depth of discharge, certification | Home ESS, C&I storage, containerised BESS |
| Traction packs | LiFePO4 (LFP) | Peak discharge current, tray dimensions, opportunity charging | Forklift, golf cart, marine, RV, AGV |
| High-voltage systems | LiFePO4 modules + BMS | Bus voltage, insulation coordination, cabinet integration | C&I cabinets, containerised systems |
Power tool replacement packs
Cordless tool batteries are a substitution market with an unforgiving constraint: the pack either clicks into the tool and the charger, or it does not. We build replacement packs across the common 18V, 21V and 14.4V platforms, matching the latch geometry, the terminal layout and the case profile rather than shipping a generic brick with an adapter.
| Platform | Voltage | Typical capacity | Note |
|---|---|---|---|
| 18V / 20V class | 18V nominal | 2.0–6.0Ah | The largest replacement market |
| 14.4V class | 14.4V nominal | 1.5–4.0Ah | Older drill and driver platforms |
| 12V class | 10.8V / 12V | 1.3–3.0Ah | Compact drivers and inspection tools |
| 21V class | 21V nominal | 2.0–8.0Ah | Higher-capacity outdoor and garden tools |
The chemistry decision matters more than the capacity number. Ni-Cd tolerates abuse and cold but has the shortest runtime and the memory effect. Ni-MH removes the memory effect and holds charge longer. Li-ion delivers the best energy-to-weight ratio, no memory effect and the longest cycle life — which is why every current platform has moved to it. Installing a different capacity is electrically safe as long as the voltage matches, but it changes runtime, weight and charge time.
Instrumentation and handheld equipment
Instrument packs are the opposite of tool packs: low current, long idle periods, and an expectation that the battery will still hold charge after months on a shelf. Design priorities shift to self-discharge rate, low-temperature behaviour and a BMS that draws microamps rather than milliamps when the host is off. See instrument lithium batteries for the detail.
How a custom project runs
- Send the requirement envelope. Mechanical drawing or maximum dimensions, voltage and capacity window, continuous and peak current, runtime target, connector, and the standards you must meet. A photo of a sample pack works if you already have one.
- Design review and pack concept. We respond with cell selection, BMS choice, protection thresholds, thermal approach and an indicative cost at your volume. Open questions get resolved here, before tooling.
- Sample build and validation. Engineering samples are assembled and put through capacity, current, thermal and drop or vibration testing as the application requires. Test data ships with the samples.
- Design freeze and documentation. Once you approve the sample, we freeze the bill of materials, the drawings and the test plan — so production has one definition of correct, and you have a document to hold it against.
- Production, test and ship. Every unit is logged against its cell batch and serial number, tested end-of-line, and packed for UN38.3-compliant transport.
Partners and platforms we support
Replacement and OEM programmes span the mainstream cordless platforms and their charger ecosystems. Because the packs are built to a frozen sample specification, a programme that starts as a replacement pack can extend into a private-label range under your own branding.
Cell sourcing runs through tier-one suppliers, with grade-A cells and batch traceability so a field issue can be traced back to the cells it was built from rather than to a shipment date.
Why work with a factory rather than a trading company
| CMX Battery (factory) | Trading company | |
|---|---|---|
| Specification control | Cell, BMS and enclosure chosen together | Restricted to what the supplier stocks |
| Custom envelope | Designed to your drawing | Adapter to an existing size |
| Test evidence | End-of-line data per unit | A generic certificate |
| Traceability | Cell batch to serial number | Usually unavailable |
| Change notification | Controlled, before it happens | Discovered at delivery |
| Engineering contact | Direct | Passed through an intermediary |
Frequently asked questions
What does CMX Battery actually build?
Three families: lithium-ion and lithium-polymer packs for portable equipment, LiFePO4 packs for energy storage and traction, and complete battery systems with matched BMS and charger. Cells are grade-A and batch-traced; assembly, BMS configuration and end-of-line test all happen in-house.
Do you take on custom pack design or only standard products?
Custom design is the core of the business. Send a mechanical envelope, voltage window, continuous and peak current, runtime target and the certification scope, and we return a pack concept — not just a quotation against an existing model.
What volumes do you work with?
Engineering samples from a single unit, pilot runs in the low hundreds, and production volumes into the tens of thousands of units per year. Tooling and NRE are quoted separately from unit cost so the scaling is transparent.
How long does a custom project take?
Typically three to five weeks from design freeze to engineering samples, depending on cell availability. Production scheduling follows sample approval, and certification testing runs in parallel where the standard allows.
What if the finished packs do not match the approved samples?
Production is built against the frozen sample specification and the approved bill of materials. If a shipment does not conform, we replace it — including freight — because a non-conforming shipment is not a shipment.
Which certifications can you supply?
UN38.3 for transport on every pack, plus IEC 62133, IEC 62619, UL 2054 / UL 1642, UL 1973 / UL 9540A for stationary storage, CE and RoHS as the destination market requires.
Can you work under a private label?
Yes. Private-label programmes cover the enclosure branding, the label and packaging artwork, the documentation set and the BMS firmware identity. Your brand ships; ours does not appear.
Where are your packs manufactured?
In our own facility, with cell sourcing from tier-one suppliers. Because assembly, BMS configuration and testing are under one quality system, the unit that ships matches the specification you approved rather than matching a different factory’s interpretation of it.
Explore related pages
- Custom battery pack design
- OEM / ODM process
- Private label LiFePO4
- Power tool replacement batteries
- Instrument lithium batteries
- Medical device battery packs
- 18650 pack calculator
- Factory tour
Start a custom pack project
Send the mechanical envelope, voltage window, continuous and peak current, runtime target and certification scope — we return a pack concept within three working days.