Battery Pack for Portable Medical Blood & Fluid Warmer


Portable blood and IV fluid warmers are used by EMS crews, hospitals and the military to help prevent hypothermia due to fluid transfers under adverse field conditions. A lightweight battery pack to power these devices is essential to the success of urgent medical operations. Epec was asked to produce a battery pack to power blood warmers used on military vehicles in order to provide an alternative to the current SLA battery, which was too heavy, too large, and not powerful enough.


Using their in-house product development and engineering services, Epec worked with the customer to jointly develop the specifications of the new product. Because this was a new development incorporating new technology, Epec was able to recommend more features that were designed into the product.

Battery Pack for Portable Medical Blood and Fluid Warmer

Epec produced the whole product from start to finish, including the design of internal components and the external plastic enclosure of the battery. Epec helped with cell selection and qualification testing, holding weekly meetings with the customer to show design changes as progress was made. Instead of an SLA battery, a LiFePO4 battery was designed to fit the customer's requirements for the product to be lightweight with fast-charging capabilities. The internal battery intelligence, including protection circuits, fuel gauges, serial communications buses (SMBus, I2C, HDQ), LED indicators, battery authentication, cell balancing, and an embedded charger were all carefully designed by Epec to the specifications of the customer.

The plastic enclosure for housing the battery's internal electronics was sealed using by Epec's in-house ultrasonic welder using tooling that was developed specifically for this project. The rugged, external plastic case was specially designed to withstand rough field conditions. Epec also designed and produced the graphic overlay with the customer's branding on the surface of the case and the membrane switch used in the fuel gauge.

Working in conjunction with Epec's design partners allowed fully functional prototypes to be developed in only 6 weeks. These were then put through environmental and regulatory testing (UL and UNDOT 38.3).

The resulting product was completely boxed so that the customer could ship immediately after receiving it. In addition to boxes that held individual batteries, larger external boxes were custom made to fit 5 boxes of individual LiFePO4 batteries for safe shipping. The external UNDOT rated, 4G grade boxes made sure the products were not damaged in transit. This additional effort translated into the customer to save time and money when shipping to their end customer.


The customer now has a new, super-portable battery for operating their blood and fluid warmers in the field. The new battery weighs only 1.25 lbs, much lighter than the 6.25 lbs battery used previously. This new battery enables medical crews to carry out their tasks with speed and efficiency without having equipment weigh them down.

See our blog post to learn more about the changing landscape for industrial and medical battery packs.

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