Rohit Gupta made this LiTiny project, a tiny LiIon charger:
In the end I had a LiIon charger capable of charging batteries @700mA restricted due to thermal dissipation limits of home made PCBs.
LiTiny- A Tiny LiIon charger for most things battery – [Link]
by Steve Taranovich @ edn.com
Any hobbyist can charge a battery quickly, but can you do it without an explosion, excessive heating or major degradation in battery cycle life?
Well many companies have managed fast charging techniques that typically use specialized algorithms. These algorithms take into account the chemistry of the battery and some sort of non-standard charging rate curve. Many device manufacturers and wireless operators are now providing a minimum two-year warranty on smart phone devices setting 800 cycles as the battery cycle life of the battery.
Charging batteries rapidly and safely – [Link]
This design is a battery management circuit, which involves the use of CAN/LIN interface. The system addresses the matter about managing rechargeable batteries. This design features an 8-output hardware configurable, high side/low switch with 16-bit serial input control using the serial peripheral interface (SPI). Two of the outputs are directly controlled using a microcontroller which are applicable in pulse-width modulation. The design also features high-speed CAN interface that is use to convert digital protocol information into an analog CAN communication.
The RD9Z1-638-4Li reference design is a Battery Management System (BMS) for 4-Cell Li-Ion battery applications featuring the MM9Z1_638 Battery Sensor Module. The RD9Z1-638-4Li is built to demonstrate the product capabilities in a 4-cell Li-Ion application where high EMC performance is required to obtain high accuracy measurements on key battery parameters. The board features an 8-pin standalone CAN transceiver to interface with others modules. Very high EMC robustness and performances are achieved by the Freescale MC33901 CAN High-Speed Transceiver. For cell balancing function and general purpose switches, the board features the Freescale MC33879 Configurable Octal Serial Switch.
The design is useful to automotive applications such as engine management, climate controls, communications and safety systems. The circuits function is suitable for a hybrid electric vehicle which monitors the condition of individual cells which make up the battery and maintains all the cells within the operating limits. It also provides information on the state of charge (SOC) and state of health (SOH) of the battery.
Intelligent 4-Cell Lithium Battery Management with CAN/LIN Interface – [Link]
by Steven Keeping @ digikey.com
The wearables market is booming. Statistics aggregator web portal Statista, notes that the global market will be worth over $7 billion this year and $12.6 billion by 2018.
Although the potential rewards are high, this is not an easy market to enter. Designing smart watches or fitness bracelets is tough; consumers expect lots of functionality, smartphone connectivity, compact form-factor, light weight, and long battery life. The introduction of highly integrated, ultra-low-power microprocessors and wireless chips has eased the design process, but squeezing out all of the battery’s power remains key to a wearable product’s success.
This article takes a look at how silicon vendors help wearables designers extend battery life by offering power-frugal displays, microcontrollers (MCU), silicon radios, and power-management chips designed specifically for ultra-low-power applications.
Extending Battery Life in Wearable Designs – [Link]
The charging system for a portable device is not always given a high priority in design but it can have a major role in the battery life of the system and, properly optimized, can allow the use of a smaller battery pack than otherwise would be needed. Not only are compact battery-management controllers needed, but intelligence also needs to be deployed tactically to allow the power system to be correctly optimized. This article will look at the needs of the Li-ion chemistry in terms of charging and what techniques can be used to maximize energy delivery and storage and summarize key solutions available for that purpose.
Lithium-Ion Batteries Call for Multi-Cycle Support to Maximize Uptime – [Link]
Determine the power absorbed by the VCVS in the figure. Solution: The VCVS consists of an open circuit and a controlled-voltage source. There is no current in the open circuit, so no power is absorbed by the open circuit. The voltage vc across the open circuit is the controlling signal of the VCVS. The voltage Vc (across 2 ohm resisitor) measures vc to be vc = 2V. The voltage of the controlled voltage source is vd = 2 vc = 4V. The current in the controlled voltage source is 6V/4 ohm= 1.5A. The element current id and voltage vd adhere to the passive convention. Therefore, p = id*vd = (1.5)(4) = 6W is the power absorbed by the VCVS.
Power and Dependent Sources – [Link]
by T.K. Hareendran:
Here is a tried and tested sample circuit of a Li-Ion battery charger that can be used to charge any 3.7V Li-Ion battery using a 5VDC (USB, Solar Panel…) power supply. At the heart of the circuit is one microchip MCP73831, available in SOT-23-5 package. MCP73831 is a highly advanced linear charge management controller for use in space-limited, cost-sensitive applications. This IC employs a constant current/constant voltage charge algorithm with selectable preconditioning and charge termination.
3.7V Li-Ion Battery Charger Circuit – [Link]
by BinksBrew @ instructables.com:
For a long time I’ve had old back up cell phones taking up space in my desk drawer. I was curious if I could put any of these old phones to some use. I can’t just throw them away so I decided to try and re-purpose one of them as a portable charger for my current smart phone.
Portable Charger for your Smartphone – [Link]
You don’t need to travel far in the Dutch countryside before you come across a traditional windmill. Now a consortium of Rotterdam-based companies are planning to build a massive wind-powered generator structure in Rotterdam harbor that will generate energy without using rotating blades. The innovative ‘Windwheel’ will work on the EWICON (Electrostatic WInd energy CONverter) principle developed at TU Delft and Wageningen University backed by a government economy/ecology innovation program.
The striking design has no moving parts but will use wind power to move charged particles (water droplets in this case) against the direction of an electric field. Charge will be transferred to a plate and then fed into the grid. Plans for the proposed generator structure are ambitious and indicate that it will contain a 160-room hotel built on seven floors, 72 residential apartments, a restaurant and other visitor attractions including an outer glass and steel ring structure containing viewing gondolas.
A Bladeless Wind-Powered Generator – [Link]
by DIY Hacks and How Tos @ instructables.com:
A “Joule Thief” is a simple voltage booster circuit. It can increase the voltage of power source by changing the constant low voltage signal into a series of rapid pulses at a higher voltage. You most commonly see this kind of circuit used to power LEDs with a “dead” battery. But there are many more potential applications for this kind of circuit.
In this project, I am going to show you how you can use a Joule Thief to charge batteries with low voltage power sources. Because the Joule Thief is able to boost the voltage of a signal, you are able to charge a battery with a power source whose output voltage is actually lower than the battery itself.
This lets you take advantage of low voltage power sources such as thermoelectric generators, small turbines and individual solar cells.
Joule Thief Low Voltage Battery Charger – [Link]