Frequently Asked Questions

Q. What's the best way to get a new project started with Fedco?

   A. Fedco has an extensive network of highly qualified Manufacturer Representatives. Please click here to find the Representative in your area. Of course, Fedco welcomes you to contact them directly. Please call (800) 542-9761 or email for fast and knowledgeable responses to your questions.

Q. What is your minimum order quantity for custom batteries?

   A. Fedco's minimum quantity order is one unit. Fedco's minimum Dollar order is $1. 

Q. How much is my custom battery pack going to cost?

   A. There are many factors that comprise the total cost of a custom battery pack. Only after a complete review of a program is it possible to provide an exact cost of a custom battery. Some considerations are:

  • Cell Chemistry

  • Number of cells required to meet voltage and capacity requirements

  • Charge/Discharge requirements

  • Environmental considerations

  • Pack enclosure requirements i.e... plastic, metal, heat shrink, other

  • Testing and Certifications

  • There are many other factors too. To help you develop a scope of your battery pack project we suggest you download this handy Battery Development Guide (BDG).   

Q. How fast can Fedco develop a custom battery pack?

   A. There are many factors that dictate the development or design cycle time of a custom battery pack. Some more basic designs can be as fast as 5-7 weeks for non-lithium based designs. However, the design cycle for a complicated Lithium-based pack that may have a plastic or metal housing can easily be as long as 16-18 weeks or longer. 

Q. Why does Fedco have to ship me sample batteries in an explosion proof steel can/drum?

   A. All Lithium-based batteries that have not been certified to UN38.3 must be shipped in a specially designed and certified can or drum to comply with U.S... DOT and FAA regulations {49CFR Part 173.185(e)}. Please communicate your questions to your Fedco Sales Representative for more complete details. Additional information can be found by visiting the Resources page, and select Shipping Regulations and scroll down to U.S.. DOT Rules  and click on Regulatory Statement for Un-Tested Batteries.

Q. Are all of Fedco's batteries going to have to ship in an explosion proof steel can/drum?

   A. No. Only Lithium-based batteries are subject to the extra precautionary shipping method which incorporates a steel can or drum. Nickel and other non-Lithium batteries are exempt. Also, once a Lithium-based battery has been certified to UN38.3 it is considered safe to ship using more conventional processes and methods. 

Q. What is the difference between a PCM (Protection Circuit Module) and a BMS (Battery Management System)?

   A. A PCM is the safety circuit installed in all rechargeable lithium-based battery packs to control over-charge, over-discharge and short circuit of the cells within the pack as prescribed in UN38.3 design criteria. A BMS also incorporates these safety features but includes an array of other control and monitoring features such as a "fuel gauge", thermal monitoring, cycle life monitoring, and can even include abuse reporting and much more.

   NOTE: For more details for these terms and many others please visit our extensive Glossary of Terms.

Q. Does Fedco have manufacturing in Asia or other parts of the world?

   A. While Fedco does source components, sub-assemblies and some finished goods from premium suppliers located in many parts of the world, Fedco proudly builds all assemblies in their factory in Fond du Lac, WI.

Q. What is the difference between a Prismatic cell, Pouch cell, and a Polymer cell?


  • Prismatic cell: commonly refers to a battery cell that is rectangular in shape with a rigid metallic can. Furthermore, the chemistry will be a descriptive qualifier of the cell, i.e.. NiMH prismatic, or Lithium Ion prismatic, etc.  

  • Pouch cell: Commonly referred to a Lithium Ion battery cell with a liquid electrolyte that is encapsulated in a flexible, bag-shaped vessel that is sealed on 3 sides. This pouch can vary in exact material but is typically comprised of a base material of Aluminum laminated with Polypropylene, Nylon and an adhesive bonding material.

  • Polymer cell: Visually a Polymer cell is very similar to a Pouch cell; however, the key difference is that a Polymer cell uses a polymerized electrolyte where as a Pouch cell will have a liquid electrolyte.

Q. *What is the typical voltage cutoff when charging a Lithium Ion (not LiFePO4) battery?

   A. The maximum charge voltage is typically 4.2V per cell; however, to achieve increased cycle life a lower cutoff can be prescribed.

Q. *What is the typical cutoff voltage when discharging a Lithium Ion (not LiFePO4) battery?

   A. the discharge cutoff voltage of a Lithium Ion battery is 3.0V per cell. However, for increased cycle life a slightly higher voltage cutoff can be prescribed.

Q. *What are the typical cutoff voltage when for charging and discharging a LiFePO4 battery?

   A. The nominal voltage of a LiFePO4 battery is 3.2V per cell, slightly lower than Lithium Ion, therefore the charge and discharge cutoff voltages are also different than that of Lithium Ion. The typical discharge cutoff voltage is 2.1-2.5V with 2.8V offering increased in cycle life. The maximum charge voltage is 3.6-3.8V.

* NOTE: The charge and discharge voltages of all batteries vary depending on temperature, exact chemistry idiosyncrasies, and manufacturer specifications. Be sure to consult Fedco and the cell manufactures' specifications for exact charge and discharge information.

Q: When to consider a hybrid battery comprised of a Primary Battery Cell + Super Capacitor (Can also be comprised of a secondary cell w/ super capacitor)

   A. Long life applications with occasional high current pulses


      •RF Monitoring

      •Automatic toilets, faucets, air fresheners

      •Asset Tracking

      •Emergency Medical Equipment

  Additional Applications:

      •Battery powered forklift – reduce size

      •Car Battery, save size and weight

      •Data Transmission – Increases run time before recharge

      •Regenerative braking – High currents can be collected instantaneously, then delivered to battery for  storage at lower current

Q. *Q: C-rate Explained

   A. C-Rate describes the continuous discharge or charge rate in relation to the cell capacity

           For example, discharging a 1Ahr cell at 1A would be a rate of 1C, and will provide 1 hour of runtime.


   •Cells in parallel will allow for increased C-rates, however, safety circuit limitations may not allow for increased charge or discharge rates

   •C-ratings from the cell manufacturer should be followed for safety and for best performance

Q: What is the Difference Between Energy Density and Power Density?

   •Energy Density is a measure of how much energy the battery can store, in a given size or mass.

        -A battery with a high energy density can power a load longer than one with a low energy density.

   •Power Density measures how quickly the battery can deliver energy.
        -A battery with a high power density can power a much greater load.

Listen to Fedco's Rep Training discussion presented on 9/22/2017 -Fedco Training Session 9/22/2017