Replace Your Project Power Supplies With Recycled Li-Ion Cells And A Switching Regulator

April 19, 2013 by Mike Szczys 16 Comments

buck-regulator

[Dr. Iguana’s] experience moving from projects powered by disposable Alkaline cells and linear regulators to recycled Lithium Ion cells using the buck regulators seen above might serve as an inspiration to make the transition in your own projects.

The recycled cells he’s talking about are pulled out of larger battery packs. As we’ve seen in the past, dead battery packs for rechargeable tools, laptops, etc., are often plagued by a few bad apples. A small number of dead cells can bork the entire battery even though many perfectly usable cells remain. Once he decided to make the switch it was time to consider power regulation. He first looked at whether to use the cells in parallel or series. Parallel are easier to charge, but boosting the voltage to the desired level ends up costing more. He decided to go with cells in series, which can be regulated with the a less expensive buck converter. In this case he made a board for the RT8289 chip. The drawback of this method requires that you monitor each cell individually during charging to ensure you don’t have the same problem that killed the battery from which you pulled these good cells.

The Ins And Outs Of Lithium-based Battery Packs

May 25, 2011 by Mike Nathan 10 Comments

lithium_batteries

So, you’ve got your awesome project built and are ready to take it on the go, but how are you going to power it? You could use a couple alkaline cells or perhaps swipe a Litihium battery pack from some infrequently used portable device – however before you do that, why not check out what [Lady Ada] has to say on the subject?

The detailed tutorial on her site discusses the different types of Lithium-based batteries and their form factors, as well as the strengths and weaknesses of each type. Voltage ratings are covered, as well as why it is important to choose a Lithium battery pack that fits the task at hand. The dangers of improperly handling batteries are clearly noted, highlighting the importance of selecting a proper charger and resisting the urge to ever wire Lithium batteries together to increase capacity.

While the bulk of the information presented is nothing new to most of our readers, it’s definitely a worthwhile read for those just starting to use Lithium battery technology in their projects.

Making Your Own Lithium-ion Batteries

September 27, 2010 by Mike Szczys 23 Comments

You can make your own lithium-ion batteries if you have a source for individual cells and a control board to match your desired voltage levels. [Bill Porter] put together a quick tutorial where he makes a 14.4V 2.2 AH battery for about $10. He picked up a set of cable-modem backup batteries (used to make sure your bundled phone service doesn’t quit working when the power goes out) and tore out the cells. After reconfiguring the connections and swapping out the controller board the original 8V battery is now 14V. This doesn’t take into account any problems with battery life and charge leveling, but that’s a whole different tutorial waiting to happen.

If this type of battery hack is child’s play to you, take a look at a more involved lithium iron phosphate build.