| Cell Phone Charger - It seems that as cell phones become more sophisticated, their operating times become shorter and shorter. If you are on the go all the time and have difficulty finding AC or DC outlets to charge your phone, you might consider this simple scheme . . . Hobby Circuit designed by Dave Johnson P.E.-August, 2009 Cell Phone Solar Powered Charger - The simple circuit below regulates the voltage from a 6v solar panel to a fixed +5v. That voltage can be fed to any cell phone or USB connected portable device, to charge its battery. The circuit uses a Reg113-5 voltage regulator from Texas Instruments . . . Hobby Circuit designed by David Johnson P.E.-January, 2011
Charge a Nickel-Cadmium Cell Reliably & Inexpensively - 12/07/12 EDN-Design Ideas A nickel-cadmium cell charger uses two ICs to achieve long charge times and accurate charge current. Rechargeable NiCd (nickel-cadmium) cells are widely used in consumer devices because of their high energy density, long life, and small self-discharge rate. As a part of one project, I needed to design a reliable and inexpensive charger for a battery pack containing two NiCd AA-size 1200-mAh cells. In the process of the charger design, I needed to solve two main problems: first, setting a proper charge-current value, and second, stopping the charging process when the cell is full to avoid overcharging. This Design Idea describes a way to overcome both problems. Design by Abel Raynus, Armatron International Inc, Malden, MA
Charge Batteries Safely In 15 Minutes By Detecting Voltage Inflection Point - Modern, battery-powered electronic products require rapid charging of NiCd, NiMH
, and other types of batteries. But if a fast charger doesn't know when to stop, it can easily cause damage. Conventional means of sensing full charge terminate charging too late. Here's a technique that stops the charging in time. Consumer demands for portability and convenience create new opportunities for manufacturers of electrical and electronic equipment. As NiCd (nickel-cadmium) and NiMH
(nickel-metal-hydride) batteries offer increased capacity and improved durability, re- chargeable-battery operation becomes increasingly common. But greater use of battery power Design by Gary Cummings, Spectra Research, Daniel Brotto, Black and Decker Corp and James Goodhart, Zilog Inc 09/01/96
Charge indicator gauges lead-acid batteries - 05/27/99 EDN-Design Ideas Although rechargeable, sealed lead-acid cells are uncommon in portable applications, they are a good choice for standby applications, such as emergency lighting and burglar alarms. A key advantagePDF has several circuits, please scroll to find this one. Design by Fran Hoffart, Linear Technology Corp, Milpitas, CA
Charge Li Ion Batteries from AC Line Voltage - 03/02/98 EDN-Design Ideas NOTE
: File contains many circuits, please scroll to find this one. Li-ion battery chargers must apply constant current when the battery charge is low and constant voltage when the battery charge is high. To avoid battery damage, the tolerance on the applied voltage must be less than 1%. The charger in Figure 1 complies with these requirements. Design by Matt Schindler, Maxim Integrated Products, Sunnyvale, CA
Charge Monitor for 12 Volt Rechargeable Lead Acid Battery - A battery is a vital element of any battery-backed system. In many cases battery is more expensive than system it is backing up. Hence we need to adopt all practical measures to conserve battery life. As per manufacturer's data sheets, a 12V rechargeable lead-acid battery should be operated within 10. IV and 13.8V. When battery charges higher than 13.8V
Charge Pump Battery Charger-+5 Volts - The circuit below will trickle charge a four cell pack of AA or AAA NiMH
batteries. The circuit draws current from the +5v available a USB connection and pumps about 70ma of current into the battery. This should be enough current to fully charge a pack of . . . Hobby Circuit designed by David Johnson P.E.-February, 2010
Charger Delivers 2.5A with 96% Efficiency - 10/12/95 EDN-Design Ideas You usually design battery chargers without regard for efficiency, but the heat generated by low-efficiency chargers can present a problem. For those applications, the charger of Fig 1delivers 2.5A with an efficiency as high as Design by Matt Schindler, Maxim Integrated Products, Sunnyvale, CA
Charger Extends Lead-Acid-Battery Life - 12/01/11 EDN-Design Ideas A circuit that properly charges sealed lead-acid batteries ensures long, trouble-free service. A circuit that properly charges sealed lead-acid batteries ensures long, trouble-free service. Fig 1 is one such circuit; it provIde as the correct temperature-compensated charge voltage for batteries having from one to as many as 12 cells, regardless of the number of cells being charged. Design by Fran Hoffart, National Semiconductor Corp, Santa Clara, CA
Charger for Deep-Cycle 12V Batteries, Pt 2 - Second article has the full construction and set-up details for this new high-performance charger.__ SiliconChip
Charger for Deep-Cycle 12V Batteries, Pt.1 - Thats not a charger...this is a charger! If you want to change deep-cycle 12V batteries correctly, this 16.6A unit is the way to go.__ SiliconChip
Charger for Gel Lead Acid Batteries - This high-performance circuit first quickly starts (Tony van Roon's and holds) the charge at 2 amp, but as the voltage rises the current will consequently decrease. When the current falls below 150mA, the charger automatically switches to a lower 'Float' voltage to prevent overcharging. At the point that a full charge is reached, Q1 will bias and the LED will light. __ Designed by Tony van Roon VA3AVR
Charger Selects between Full & Trickle Charge - 06/18/98 EDN-Design Ideas The circuit in Figure 1 charges a lead-acid battery at full charge voltage while monitoring the charge current. When the charge current decays to approximately 0.1C, where C is the capacity of the battery, the charger automatically switches to a lower trickle-charge voltageFile has several circuits, please scroll to this one Design by Ajmal Godil, Linear Technology Corp, Milpitas, CA
Charger serves load while charging batter - 07/03/97 EDN-Design Ideas The battery-charger circuit in Figure 1 monitors the battery voltage and automatically initiates a recharge if required. Its output-current capacity is sufficient to simultaneously charge the battery and supply the load. Design by Bernard Konrad, Maxim Integrated Products, Graefelfing, Germany
Charging NiMH
Cells - The latest rechargeable cell on the market is Nickel Metal Hydride (NiMH
). It has a cell voltage of 1.2v (called "Terminal Voltage" as it is the voltage across the terminals of the cell) and a capacity higher than previous types of cells. It's a real advancement in technology __ Designed by Collin Mitchell
Charging a 24v Battery Charger from a 12v Source - A while back I received an email from a Discover Circuits visitor. He wanted to know how he could use a single 12v solar panel to charge a 24v lead acid battery bank. He said he used the 24v battery to run an emergency 120vac power system. By using the higher 24 volts instead of 12v, his DC to AC inverter could pump out more peak power, for starting things like well pumps and window air conditioners. . . . Circuit by David Johnson P.E.-July, 2017
Choosing & using Nickel-Metal-Hydride (NiMH
) Rechargeable Batteries - The number of portable gadgets that we use has grown substantially in the last few decades. Many of these, such as TV remote controls, some digital cameras, handheld GPS units, and flashlights, are designed to operate on either disposable alkaline batteries or rechargeable, and hence reusable, Nickel-Metal-Hydride (NiMH
) batteries. __ Designed by Stefan Vorketter
Circuit Charges Lead Acid Batteries - 02/03/97 EDN-Design Ideas The circuit in Figure 1 charges lead-acid batteries in the conventional way. A current-limited power supply maintains a constant voltage across the battery (2.4V/cell or so, as specified by the battery manufacturer until Design by Dana Davis, Maxim Integrated Products, Sunnyvale, CA
Circuit Charges Lead Acid Batteries - Integrated App Note 621 -- A flyback converter implements a current-limited power supply to charge lead-acid batteries. The MAX668 PPM controller limits the output current, and the flyback transformer provides isolation and flexibility for input voltages both above and below the battery voltage. The MAX4375 current-sense amplifier monitors the charging current and uses its internal comparator that below a designed threshold the flyback converter can switch to a lower charging voltage for trickle-charge mode. The circuit shown in Figure 1 charges lead-acid batteries in the conventional way: A current-limited power supply maintains a constant voltage across the battery (approximately 2.4V/cell, as specified by the battery manufacturer) until the charging current decreases below a current threshold defined by the capacity of the battery. __ APP 621 Aug 26, 2011
Circuit Indicates Battery Charge Current - This circuit was inspired by a company needing a DC current indicator light which was small enough to be molded into a medium size 28v rechargeable battery assembly. They specified that they wanted the circuit to turn on the LED indicator light with 500ma or more of battery charge current . . . Hobby Circuit designed by Dave Johnson P.E.-January, 2011
Circuit Indicates Health Of Lithium-Ion Batteries - 05/14/09 EDN-Design Ideas A simple inexpensive circuit quickly indicates a battery pack's health Design by Fritz Weld, Friedberg, Germany
Circuit Prevents Deep Discharge Of Batteries - 09/26/96 EDN-Design Ideas To avoid the deep discharge that can destroy or shorten the life of a rechargeable battery, you must disconnect its load before the discharge is complete Design by Ron Clark and Larry Suppan, Maxim Integrated Products
Circuit safely Deep-discharges NiCd battery - 04/29/99 EDN-Design Ideas – NOTE
: Scroll to find this circuit. Nickel-cadmium (NiCd) batteries can possess an undesirable memory effect due to partial discharges. The remedy is a complete discharge before charging again. Figure 1a shows a simple circuit that performs this feat. Design by Jim Hagerman, Science & Technology International, Honolulu, HI
Colman_Lantern3_Modified - While shopping at a sporting goods store one day, I spotted a compact LED lantern. It looked like the kind of lantern I could modify. The lantern LEDs were grouped into three sections of 7 LEDs each, oriented into 120 degree angles. The LEDs were standard T 1-3/4 epoxy types. The lantern had a three mode switch which selected between off, full power and half power modes. At the half power mode, only half of the 21 LEDs were illuminated. At full power all LEDs were illuminated. . . . Hobby Circuit by David Johnson P.E.-September, 2017
Collection of Battery Chargers - Collection of battery charger circuits __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Constant Current Battery Charger - A simple method of charging a battery from a higher voltage battery is shown in the circuit below to the left. Only one resistor is needed to set the desired charging current and is calculated by dividing the difference in battery voltages by the charge current. So, for example if 4 high capacity (4000 mA hour) ni-cads are to be charged at 300 mA from a 12 volt battery, the resistor need, __ Designed by Bill Bowden
Constant Current NiCad Charger - The schematic for this charger is pretty simple. You can charge from 1 to 20 +/- nicads at a constant current of from 20 to 200 ma +/-. The circuit I modified from an article in July 1977 “73 Amateur Radio Magazine.” __ Designed by Pete Christensen
Current Indicator for Battery Chargers - This circuit was inspired by a company needing a DC current indicator light which was small enough to be molded into a medium size 28v rechargeable battery assembly. They specified that they wanted the circuit to turn on the LED indicator light with 500ma or more of battery charge current. . . Circuit by Dave Johnson P.E.-January, 2011
DC Input Controls Efficient Battery Charge - 03/02/95 EDN-Design Ideas Designing a single-rate battery charger by using a current-mode switching-regulator controller is usually not a challenge. If operating at its current limit, the controller provIdeas a constant output current that you can easily adapt to battery charging. However, the design gets more complicated if you must vary the charging current by using a dc control signal. This task is especially difficult with high battery voltages. Providing high-side charging-current sensing to eliminate sense resistors in series with battery ground is desirable. Design by Dimitry Goder, Linear Technology Corp, Milpitas, CA
Device for Maintaining Car Batteries - When we do not drive our cars for extended periods of time, the abandoned rechargeable batteries become fully discharged. Sometimes, these get damaged, too. Batteries have self-discharging rates that depend on their __ Electronics Projects for You
DIY Cell Phone Charger - It seems that as cell phones become more sophisticated, their operating times become shorter and shorter. If you are on the go all the time and have difficulty finding AC or DC outlets to charge your phone, you might consider this simple scheme . . . Hobby Circuit designed by David A. Johnson P.E.-August, 2009
Do It Yourself Portable Cell Phone Charger - It seems that as cell phones become more sophisticated, their operating times become shorter and shorter. If you are on the go all the time and have difficulty finding AC or DC outlets to charge your phone, you might consider this simple scheme. . . Circuit by David Johnson P.E.-August, 2009
Dual Smart Battery Charger Simplifies Battery Backup for Servers - DN342 Design Notes__ Linear Technology/Analog Devices |
