A more realistic battery model includes a resistive divider that a capacitor partially shunts (Figure 1). In addition, a battery’s no-load internal resistances may differ significantly from their ...

You can also go the 9v battery route plugged into the on-board regulator of the Arduino but the low mAh rating of a 9v won’t allow your project to stay running for very long.

Arduino developers and hobbyists looking for a portable battery shield to powered their projects might be interested in a new shield called the EnergyShield Arduino rechargeable battery.

The direct current internal resistance (DCIR) characteristic of the battery is an important characteristic of the battery. The discharge process at a temperature of 25°C is studied in this article.

U-M engineers have identified internal resistance, measured immediately after cells are made, as a key indicator of how long a battery will last.