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Accutronics - An Ultralife Company
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  7. CMX Series Batteries and Chargers

CMX Series Batteries and Chargers

The Medical Market Requirements

Rechargeable batteries are usually required in portable and transportable medical equipment, either to power the equipment directly or to provide a back-up power source.

As many hi-tech medical devices such as acute ventilators, anesthesia workstations and intra-oral scanners free themselves from the confines of mains electricity there is a growing demand for rechargeable batteries with a high power capability that can safely and reliably deliver energy to these devices.

Medical Original Equipment Manufacturers (OEMs) have long looked to battery companies to provide the answers, but have often been let down by a lack of understanding of their requirements, this may be due to increasing regulatory framework, demanding development schedules or the need for products to be truly innovative at a time when medical OEMs are under pressure to reduce costs and increase the value in each product they sell.

It is against this background that Accutronics has developed the Entellion CMX series of Lithium ion batteries and chargers. CMX has been specifically designed for medical OEMs following extensive research and discussion with customers and hospitals. CMX series batteries and chargers are available off-the shelf or can be easily customised to meet a particular OEM requirement.

The Technology: Lithium Ion

CMX series batteries use rechargeable Lithium ion cell technology throughout. Lithium ion has a proven track record in providing safe, reliable power to devices we use in our everyday lives and is now used to power everything from smart phones to electric cars.

‘Lithium ion’ is the umbrella term for a battery technology that uses the intercalation of Lithium ions between a graphitic anode and a layered oxide cathode. The technology provides high energy density, excellent safety, low self-discharge and outstanding cycle life.

Through careful selection of cathode formulation and cell construction a wide range of Lithium ion cells have been developed that provide specific performance attributes, such as high discharge capability or high volumetric energy density.

CMX820P or CMX810M?

The two batteries in the CMX range use different cell types to provide specific performance attributes which are required for the medical device market.

>  For devices that draw very high levels of power, the CMX820P offers 330W discharge capability.

>  When energy density and high power discharge are both important, the CMX810M balances size and power capability.


CMX series batteries have a voltage output of 28.8V and operate between 33.6V and 22.0V. These high voltages allow medical devices to be powered more efficiently through a reduction in current consumption.



Available in two sizes, CMX series batteries contain either eight or sixteen cells. All cases are manufactured from tough UL94V-0 rated plastic and are coloured ‘traffic white’ to better complement the medical environment.  A pull tab on the end of the battery provides easy removal from the device.


CMX series batteries feature an industry standard 7W2S connector. Both power and signal connections (battery positive, battery negative, SMBus Clock, SMBus Data, Battery Present and safety sense resistor) are made through this interface. Mating halves are available in numerous configurations to suit any orientation and configuration in the OEM equipment. The connector is protected from accidental damage by two ‘tusks’ that protrude from the battery casing.

Regulatory Certification

CMX series batteries comply with the regulatory certifications necessary for use in medical devices. In terms of safety they meet the requirements of IEC 62133:2012, UL 62133 and CAN CSA E62133:13 which allows seamless integration into any battery powered medical device being certified to UL / IEC 60601-1.  All CMX series batteries meet the requirements of The Transport of Dangerous Goods, Methods of Tests and Criteria, UN ST/SG/AC.10.11 Rev5 section 38.3 which is a mandatory requirement for the transportation of Lithium ion batteries. All CMX series batteries have an energy rating less than 100 watt hours which means that they are more easily offered for transport whether shipped by road, sea, air or rail.


CMX series batteries are available as a standard product with Entellion branding or can be easily customised to meet the specific needs of the OEM. Customisation options include product labelling, case colour and software set-up. Custom versions of CMX series batteries can also be programmed to include a unique ‘authentication key’ which allows your device to interrogate your customised battery and determine if it is a valid part thus enabling batteries not deemed to be valid to be rejected by the host device. SHA-1 authentication helps protects your aftermarket sales revenue and can prevent fraudulent warranty claims which may result from the use of non-approved batteries.

Active and Passive Protection

Product safety is of paramount importance. Accutronics follow industry best practice when implementing battery protection. All CMX series batteries feature active and passive protection systems to ensure they remain totally safe during transportation, storage and use. Batteries are internally protected from being overcharged, over discharged, overloaded or short circuited. Thermal sensing provides alarms if the battery is too hot and will remove the battery from circuit if its temperature during charge or discharge exceeds safe levels. A redundant, secondary active protection circuit permanently disables the battery if an unsafe condition exists. These ‘nested’ levels of protection ensure that CMX Series batteries remain safe under all conditions.

Cell Balancing

CMX series batteries contain cell balancing circuitry which works to minimise the minor differences in cell capacity, boosting available capacity and extending battery life.

Smart Battery Functionality

CMX series batteries are intended to be integrated into medical devices as part of a smart power management system. In such a system the battery, smart charger and the host device communicate with each other to maximise product safety, efficiency and performance. By only requesting charge when they need it, smart batteries charge more efficiently and use less power. Smart batteries maximise the runtime per discharge cycle because they tell their host device when to shut down based on a highly accurate remaining capacity prediction. This method is superior to dumb systems that use a fixed voltage cut-off. Host medical systems that use smart battery technology can provide accurate, meaningful runtime information to users – of vital importance in a medical environment where power failure is not an option.

Smart Fuel Gauging

Each CMX series battery constantly tracks its own capacity whether it is being charged, discharged or stored.  The battery fuel gauge uses an impedance tracking algorithm to predict remaining capacity so OEMs can provide users with a device runtime they can trust.  Battery capacity is reported in milli-ampere hours (mAh) to a resolution of 1mAh. The real time capacity is reported in both mAh and as a percentage (of the original design capacity and of the last time the battery was charged). An LCD bar graph visual state of charge indicator on the battery displays battery capacity in 20% increments.

Smart Charge Control

CMX series batteries maximise charge efficiency and safety by requesting their own charge voltage and current from a compatible smart charger. This method ensures that batteries are only charged when they need to be, and at the most appropriate voltage and current for the prevailing environmental conditions. Smart charging future-proofs the system as it allows for future batteries to be developed with higher storage capacity and different charging regimes without having to replace the chargers in the field.

Smart Communication

Being SMBus (System Management Bus) and SBDS (smart battery data specification) compliant means that CMX Series batteries comply with an open standard which is easily accessible by OEM device developers. Along with the SBCS (Smart battery charger specification) and the SBSMC (Smart Battery System Manager Specification) the SBS standard describes all of the information that can be communicated between smart batteries, chargers and host devices.

50ABB002 - Internal Single Channel Charger

50ABB002 is PCBA level charging module which has been designed to offer single channel smart charging of a single CMX series battery at currents up to 2500mA. An I²C interface allows host control of the charger and for the host to interrogate the battery. Up to eight charger modules can be integrated into a system as each has its own programmable I²C address. Each charger module can have both its charging voltage and current programmed by the host device, offering increased flexibility. The charger has a footprint of just 60mm x 120mm and weighs <74g, allowing it to be easily designed into OEM devices with minimal effort.

Why specify an Entellion CMX Series Battery & Charger in your next product?

  • Designed specifically for professional OEMs by a company who provide rechargeable batteries to many of the world’s leading portable electronic device OEMs.
  • Available off-the-shelf in quantities from one, to tens of thousands, either as a standard product or customised to meet your needs.
  • High tech solution utilising the latest lithium ion and fuel gauging technology.
  • Backed up with unrivaled technical and commercial support.

Additional Information

You can find more information on the batteries in this series by clicking on the links on this page. If you require technical or commercial assistance please send us an email or complete our enquiry form.

  1. Accupro

    Ask Accutronics to design & manufacture a unique battery or charger for your new product through our Accupro design & manufacturing service

    Click Here
  2. Inspired Energy

    Accutronics is the sole distributor for the wide range of standard smart batteries, chargers & accessories from Inspired Energy

    Click here
  3. Entellion

    Entellion products are smart, innovative portable power products, designed to meet the emerging needs of feature-laden devices in professional markets.

    Click Here
  4. Ultralife

    Standard cells, batteries, chargers and other products to help decrease your development costs and compress your time to market.

    Click Here