Next one used in the design is the TL431 adjustable precision shunt regulator IC, again a very cheap and easy to use component available everywhere.įirst, note that this quick design does not attempt to replace a dedicated Li-ion battery charger circuit. This time I’m giving you a crude circuit with the help of the good old adjustable linear voltage regulator IC – LM317 (perhaps you may have a dozen in your junk box).
You can find a number of such charger circuits here, but most of them are based on dedicated Li-ion battery charger ICs in MCP,LTC,TP… series (that’s good). Obviously, you need a standalone charger to restore your Li-ion cells/batteries lifted from the old/defunct laptop battery packs. Be very careful, in a sleepy midnight moment one of my laptop battery packs went up in smoke instantly! Never let your metal tool to make an accidental contact between any solder points inside. If you are going to attempt this, you must note that there is a very real possibility of a fire hazard if you hastily pry the lid of a laptop battery pack out. If you know what you’re doing, this is a great way to stock some ‘low-grade’ Li-ion batteries for your little electronics hobby projects.
Throw away the dead batteries and re purpose the rest. Often, you’ll get half dozen 18650 single-cell Li-ion batteries. You can take the batteries apart and re-use them if you are lucky. These battery packs cannot be repaired by simply replacing the faulty 18650 lithium-ion cells with new cells. A few weeks ago, I started collecting defunct laptop batteries, particularly the modern smart battery packs.