Interesting article from IEEE Spectrum about the potential benefits of developing a usefully rechargeable lithium-oxygen cell (for use, most importantly, in electric cars) and the challenges that remain for that research. So-called “air batteries,” in which one of the reacting chemical species is atmospheric oxygen, are already widely employed, for instance, in hearing-aid batteries, which are commonly zinc-air cells with a piece of adhesive film that must be removed before use to allow atmospheric oxygen onto the cathode. The know-how to make lithium-air cells is available right now; the hard part is making the reverse process practical over many recharging cycles. [via]
The quest for a rechargeable lithium-air battery – [Link]
This Valentine instructable shows a pair of Hearts that unite to become one! The homopolar motor is the simplest form of electric motor, consisting of a battery, a conductor, and a magnetic field. The flat Heart shape is the most basic of homopolar motors. The Heart with legs is the next most simple shape. With a little ingenuity, the two shapes can be combined to unite into one spinning body. In this Instructable, I show how to make this special 2-piece homopolar motor with a bass speaker, some coins, a battery and two pieces of copper wire. A neodymium magnet can also be used instead of the bass speaker and coins. This is a great display for Valentines Day…or any day of the year!
How-To: Valentine motor - [Link]
This device allows solar cell arrays to be connected to either conventional lead-acid, sealed lead-acid, or lithium storage batteries without fear of overcharging. It allows two different electrical loads to be driven from the batteries at two different charge states to maximise power usage efficiency.
Photovoltaic Solar Battery Regulator and Load Controller – [Link]
This battery charger is for 12V Sealed Lead Acid (SLA) battery. It is actually a half-wave rectifier. It only charges the battery on every half cycle.
12V Battery Charger for Sealed Lead Acid - [Link]
Nikolaus Gradwohl needed some battery packs to power his devices so he wrote a openscad-script that generates battery compartments. The software handles various battery types from AAA to D and can generate compartments for even and odd battery numbers. The devices are printable and the only thing you need to add are little metal stripes for the contacts. [via]
Print your own battery compartments - [Link]
This project is able to power a USB device using two standard AA batteries and an electronics circuit. The circuit is based on LT1073 DC/DC converter to convert the 3V to 5V needed by USB. In that way it can power the USB device on the go.
USB Battery Pack - [Link]
Graham explores a popular method for charging NiMH cells – float charging.
Float charging has the advantage of keeping the cells fully charged and ready to use without the potential damage of long-term trickle charging or the cost of low-discharge cells. This approach works because NiMH cells do not have the memory problems associated with Nicads.
Float Charging NiMH Cells - [Link]
This is a blog that documents various Arduino projects. The author is living to a Solar Powered home that offers a wealth of ways to use Arduino’s and connected sensors. He shows how to use a Xbee module and how to make an Arduino Solar Battery Monitor.
TropicArduino: Arduino projects – [Link]
Here is a lead acid battery charger circuit using IC LM317. The IC here provides the correct charging voltage for the battery. A battery must be charged with 1/10 its Ah value. This charging circuit is designed based on this fact. The charging current for the battery is controlled by Q1,R1,R4 and R5. Potentiometer R5 can be used to set the charging current. As the battery gets charged the the current through R1 increases.
Lead Acid Battery Charger Circuit – [Link]
Making LED devices portable can be a little bulky due to the batteries. The Joule Thief solves that, by boosting a single AA battery’s voltage to a high enough level to light a LED. Check it out.
Joule Thief – use LEDs with only one AA battery! - [Link]