Submitted by webmaster on Tue, 05/28/2019 - 10:41

To the uninitiated, the language of batteries can be confusing or intimidating. How does an amp-hour differ from a Coulomb? How does Lithium-Ion compare to Lithium-Poly? Will a 100mAH battery provide a steady current of 200mA for thirty minutes?

This article does not intend to answer all the questions you may have regarding batteries. Later, we will point you to several resources we have found helpful if you want to do a deep dive. But for now, we intend to maintain a narrow focus on selecting the right battery for one of the projects featured on (the "Site").

Type of Battery

Primary or Secondary?

A primary battery is one which must be discarded after it has been discharged. A secondary battery is one which can be recharged and used again. Since a chief focus of projects on the Site is storage of electricity generated by solar energy, we are interested mainly in secondary (rechargeable) batteries. Primary batteries may still be used on projects on the Site (for example, as a backup or supplemental power supply) but our primary interest will be in secondary batteries.

Battery Chemistry


  1. All About Circuits Vol. 1 - Direct Current (DC). Accessed 2019-05-28.
  2. A Guide to Understanding Battery Specifications. MIT Electric Vehicle Team, December 2008.
  3. Fedco Batteries. Cell Configurations. Accessed 2019-05-28.
  4. Battery University. BU-302: Series and Parallel Battery Configurations. Accessed 2019-05-28.
  5. The Rechargeable Battery Association | Types of Batteries.