The charger included with the Eee is rated at 9.5v, 2.315A. There isn’t a fixed voltage regulator available for this exact voltage.The circuit designed around LM2576-adj which is an SIMPLE SWITCHER 3A Step-Down Voltage Regulatoradjustable regulator IC from National Semiconductor.This circuit is intended for people who have had experience in constructing electronic projects before. The circuit design and build process are provided simply as a reference for other people to use.source

This article describes the construction of an AA battery powered 67 1/2 volt “battery”. This new rechargeable “B battery” is slightly smaller than the original Eveready 467 battery and is the same weight. The substitute battery can be made in different voltages and can be powered from a wide variety of sources.source

This charger will quickly and easily charge most any lead acid battery. The charger delivers full current until the current drawn by the battery falls to 150 mA. At this time, a lower voltage is applied to finish off and keep from over charging. When the battery is fully charged, the circuit switches off and lights a LED, telling you that the cycle has finished. source

This is s simple circuit of a CEMF charger.The CEMF charger uses the CEMF (counterelectromotive force) from an inductor to charge a capacitor to high voltages from a low voltage source.When the button is pushed the inductor will generate a small amount of CEMF that will charge the capacitor. When the button is released the inductor generates more CEMF that charges up the capacitor further. source