12V 7.2Ah SMF Battery Charger: Smart Approach for Smart devices by Smart People !!
Difficulty Rating: 5/10 Abstract: This project gives an overview of the Sealed Maintenance-Free (SMF) Lead-Acid Rechargeable Battery charger using 3-pin IC LM-317 as voltage regulator and opamp IC LM-324. In case of a simple battery charger, when the battery is fully charged and is left plugged in for more than a day or two, the battery may get damaged. In order to protect the battery from this major risk, the proposed battery charger is designed in such a way that the charging current falls gradually as the charging progresses. So the battery can be left plugged into this charger indefinitely, and it won't bother it in the slightest. Designing the Circuit: Click the image to view the enlarged version The LM317 is an adjustable three-terminal positive-voltage regulator capable of supplying more than 1.5A over an output-voltage range of 1.25 V to 37 V. It is exceptionally easy to use and requires only two external resistors, R 2 ’ and R 2 ” (R 2 ...