The LTC®4121 is a 400mA constant-current/constantvoltage (CC/CV) synchronous step-down battery charger. In addition to CC/CV operation, the LTC4121 regulates its input voltage to a programmable percentage of the input open-circuit voltage. This technique enables maximum power operation with high impedance input sources such as solar panels.
An external resistor programs the charge current up to 400mA. The LTC4121-4.2 is suitable for charging Li-Ion/ Polymer batteries, while the programmable float voltage of the LTC4121 is suitable for several battery chemistries.
LTC4121/LTC4121- 4.2 – 40V 400mA Synchronous Step-Down Battery Charger - [Link]
by Superbender @ instructables.com:
Winter just arrived. The enemy of all batteries. Last year this was the season the auxiliary battery of my T3 VW camper bus bit the dust. This likely happened because I neglected to take care of it over the winter months during which the bus is typically parked in my garage. When the auxiliary battery is really dead dead, aka croaked, it is not only not working, but it also prevents the main battery used for starting/driving of the bus to be properly charged when driving. Not a good situation if you are somewhere out in the woods and eventually need a ride back to civilization. After almost getting stuck in the boonies, I decided to build a two-channel battery cycle charger that is supposed to keep both batteries happy and healthy for these winter months. You can see this project documented here.
ATtiny85 Two-Channel Lead Acid Battery Charger - [Link]
In a serious case of out-of-the-box thinking, a design team at Roost in Sunnyvale California have come up with a method to add Wi-Fi connectivity to your old smoke or carbon monoxide alarm by just swapping batteries. Your smoke detector uses a 9 V PP3-type battery right? The new Roost battery contains 9 V lithium cells together with a processor and Wi-Fi chip in the standard PP3-sized battery outline. It monitors the battery voltage and power drain to alert you via Wi-Fi and a smartphone app when the alarm has been triggered, even if you are not at home.
New Battery Smarts-up your Smoke Detector - [Link]
In this project, we are building a programmable single/multi cell lithium battery charger shield for Arduino. The shield provides LCD and button interface which let the user set the battery cut-off voltage from 2V to 10V and charge current from 50mA to 1.1A. The charger also provides the ability to monitor the battery status before and during charge.
The charger is based on LT1510 Constant Current/Constant Voltage Battery charger IC and controlled by Arduino UNO. The display on the shield is Nokia 5110 LCD which is very simple to use and still available on the market. There are two different battery connectors available on the shield, a two contact screw terminal block and a right angle 2mm JST-PH connector.
DIY Lithium Battery Charger Shield for Arduino - [Link]
Josh Levine writes:
It can be nice to know how much battery power you have. It becomes critically important with LiPo batteries since you can permanently damage them by running the voltage down too low. Typically battery voltage detection requires adding a circuit with extra parts and their associated power requirements. Wouldn’t it be great to be able to do this using nothing but software? Read on for a no parts, no pins, no power solution…
Battery fuel gauge with zero parts and zero pins on AVR - [Link]
by Darren Quick @ gizmag.com:
It can be a herculean task to get kids to eat their vegetables, but they’ll happily chow down on things they aren’t supposed to. If one of those things is a button battery, serious injuries can result in the form of burns to the esophagus or tears in the digestive tract. Researchers may not have found a way to stop kids swallowing button batteries, but they have found a way to make such culinary no-nos safer.
Coating makes swallowing batteries safer for curious kids - [Link]
by Mohamed Ismail @ edn.com:
Other than generous helpings of coffee, what helps industry decrease time to market, drive down cost, and focus more of the design cycle on innovation? Hint: standardization. By defining protocols and operating characteristics, standards have impacted all aspects of technology: device package sizes, pin outs, data and communication interfaces, software drivers, connectors, ESD ratings, environmental compliance, test fixtures. The list goes on and on. The more detailed a specification, the better equipped are developers for defining products that serve the marketplace. If there is any doubt about the value of tightly defined standards, go into any two clothing stores and buy the same size shirt.
USB battery charging rev. 1.2: Important role of charger detectors - [Link]
The bq2510x series of devices are highly integrated Li-Ion and Li-Pol linear chargers targeted at space-limited portable applications. The high input voltage range with input overvoltage protection supports low-cost unregulated adapters.
The bq2510x has a single power output that charges the battery. A system load can be placed in parallel with the battery as long as the average system load does not keep the battery from charging fully during the 10 hour safety timer.
BQ25100 – 250-mA Single Cell Li-Ion Battery Charger - [Link]
by Rob Matheson @ phys.org:
Stream video on your smartphone, or use its GPS for an hour or two, and you’ll probably see the battery drain significantly. As data rates climb and smartphones adopt more power-hungry features, battery life has become a concern. Now a technology developed by MIT spinout Eta Devices could help a phone’s battery last perhaps twice as long, and help to conserve energy in cell towers.
Beating battery drain: Power-conserving chip may increase smartphone battery life - [Link]
An application note (PDF) from MAXIM:
The typical specification for lithium coin-cell batteries has been to provide a 10-year battery lifetime in the absence of system power. End users should evaluate the anticipated lifetime in their specific application, especially for those that exceed typical commercial environments or that need to last more than 10 years. This article gives the reader an overview of the major factors affecting the lifetime of an IC that can be powered by either the system power or a lithium battery for a backup supply.
Lithium coin-cell batteries: Predicting an application lifetime - [Link]