Battery Lifetimes

  •  Which battery lasts the longest, non-rechargeable batteries or solar charged rechargeable batteries?
  • How does the lifetime of the battery change after a rechargeable battery has been discharged and recharged.

Recommended Items:

  • Different brands of alkaline batteries, non-alkaline batteries and rechargeable batteries.


Concepts Used:

  • Chemistry, Batteries


Batteries are made by placing two different metals, one negatively rich and the other positively rich, in a solution (called an electrolyte) that first, will allow electrons to flow between the metals and second, will to some  extent, replenish the electrons lost in the negatively-rich metal.  The two metal ends of the battery are called electrodes.  The combination of the electrodes and the electrolyte solution makes what is called an electrochemical cell. When the battery is not connected to a device, the electrons will gather on one electrode, making it negatively charged, while the other electrode will become positively charged.  Connecting the battery to a device creates current as the electrons flow from the negative electrode , through the device (like a light bulb, a radio or a voltmeter), back to the positive electrode.

Non-rechargeable batteries are designed to only be used once, whereas rechargeable batteries are designed to be reused.  This means that the electrochemical cell in a rechargeable battery can be replenished by applying a voltage which allows the electrochemical cell to run in reverse.  Also, not all rechargeable batteries are capable of being completely recharged after each discharge cycle.  That means that the amount of energy that the battery can supply will decrease a bit after each discharge cycle.

This experiement compares the lifetime of standard alkaline batteries with that of rechargeable batteries.  By connecting a battery to an electrical device, for example, using batteries to power a flashlight and monitoring the performance of the device over time (for a flashlight, the strength of the flashlight beam) it is possible to determine the lifetime of the battery.  Different batteries will perform differently and rechargeable batteries are known to experience changes in lifetime after multiple recharging cycles.

Read More:

How Stuff Works