An article on cheap battery-powered micro-controller projects by Nerd Ralph: Once the higher cost of a 9V battery is factored in (about $1.50), the 9V battery is clearly more expensive than a 3V coin cell. However you may have a cheap source of 9V batteries – smoke detectors. I’ve found my smoke detectors start beeping […]
Tag Archives: battery
App note: Getting the most out of the MAX14920/MAX14921 high-accuracy battery-measurement AFEs
An application note from Maxim on getting the most out of the MAX14920/MAX14921 high-accuracy battery-measurement AFEs: The MAX14920/MAX14921 is a high-accuracy battery-measurement analog front-end (AFE) ideal for cell balancing and battery-measurement applications. The performance of the system in which the MAX14920/MAX14921 is used, however, depends highly on the components that support and surround it. This application note provides […]
Tear down of a cheap external USB battery
cpldcpu did a teardown of an external USB battery: The device has a USB micro-b socket which is used as 5V input for charging, and a normal USB-A socket as 5V output. The output power can be turned off and on by a toggle button. There are LEDs to indicate active power out (blue) and charging (red) […]
App note: Lithium-Ion battery recycling made easy
An app note from Maxim: Lithium-Ion battery recycling made easy This application note describes how to recycle lithium-ion (Li+) batteries from older devices for use in other electronic devices, such as toys. This can all be done without the need for a microcontroller (or the required software). One challenge is that the battery charger in these […]
SMPS with battery backup and NiMH charger using the LM2595
Giorgos from PCBheaven designed an SMPS buck regulator with 2xAA NiMh battery trickle charger and power failure output: Some time ago I presented a small circuit with the MCP1640, the High Efficiency Battery Boost Regulator using the MCP1640. My original intention was to combine it with this one and make a complete power supply unit with […]
Solar panel charging circuit
Solar panel charging circuit: A special circuit is needed when charging a battery from a Solar Panel. When the solar panel is not providing any power the battery might start draining current into the panel. One common solution is to have a diode in series with the charging circuit to keep the current from going […]
App note: Using the deep under-voltage recovery mode (DUVR)
AVR354: Using the Deep Under-Voltage Recovery Mode (DUVR) [PDF!] DUVR mode represents the intelligent pre-charge mode for Atmel’s smart battery microcontrollers ATmega16HVA, ATmega8HVA, ATmega8HVD and ATmega4HVD. It is intended for controlled charging of cells even when the cell voltage is below the minimum operating voltage of the chip. The charging is done without using a […]
App note: USB HID lithium-ion battery charging via USB with ATmega16/32U4
This app note discusses how to use the Atmel® EVK527 evaluation kit to charge Lithium-Ion (Li-Ion) batteries using USB connection as power supply: This document (PDF!) describes an application running on the Atmel EVK527 evaluation kit. The EVK527 is dedicated to the Atmel ATmega16/32U4. The USB offers a 5V power supply on the VBUS pin. […]
Powering projects from Li-polymer cells
Sjaak gave an example of powering a project from Li-polymer cells. His design uses the MCP73811 to handle the charging, while the TPS61200 DC/DC converter maintains 3.3V on it’s output regardless of the battery voltage. Via the forum.
App note: Find the right battery for your project
Maxim describes how to select the batteries best suited to a specific project. The main performance metric for batteries is, of course, battery life. On the surface, this is a simple spec, but in truth it has many dimensions. These include the system’s load profile (how much of the time it spends using full load […]
Monitoring battery voltage to calculate capacity with an Arduino
Eric built himself a battery monitoring system based on the ATmega328 Development Kit he received as a prize in our 7400 contest. He drained a 9V battery with 100mA of current and monitored the voltage drop until total depletion. He used this data to estimate how much time is left until depletion. The 100mA constant […]
App note: Battery/charger load switch approximates ideal diode
Portable devices require a circuit that switches the power supply between battery and charger. This is usually done by using a diode on the battery line – when the charger is plugged in, the diode is reversely polarized and disconnects the battery from the rest of the circuit. This method however has drawbacks, namely power […]
The basics of USB battery charging: a survival guide
An introduction to USB battery charging: a survival guide Arguably the most useful part of USB’s power capabilities is the ability to charge batteries in portable devices, but there is more to battery charging than picking a power source, USB or otherwise. This is particularly true for Li+ batteries, where improper charging can not only […]