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Battery Monitors / Testers
Battery Monitors
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Last Updated: November 30, 2017 07:38 AM

Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

Battery automatic power-off has simpler Design  -  31-Mar-05 EDN-Design Ideas Simplified circuit provIdeas timed battery cut-off to save power __ Circuit Design by Yongping Xia, Navcom Technology, Torrance, CA

Battery Characterizer  -  Schematic Only   loads charged nicad and NiMH
battery packs and measures milliamp hour capacity. (18f252) __ Designed by Jon Fick

Battery Desulphation Progress Monitor  -  A number of readers have asked how to tell when the Lead-Acid Battery Zapper has done its job and battery desulphation is complete.  In the author?s experience, batteries that are going to respond to this treatment will generally show quite a high peak voltage across the terminals at the beginning of the treatment.  If this|

Battery Discharge Monitor  -  Here is a battery monitor circuit which disconnects the load when the battery is discharged, preventing a deep discharge which could cause permanent battery damage.  The battery is automatically reconnected when a battery charger or other DC source is connected across the load.  Select a relay which requires less than 100ma coil current and with contacts capable of handling the load and charging __ Contact: Charles Wenzel of Wenzel Associates, Inc.

Battery discharger  -  This is a page with a few circuits which may be useful for monitoring the state of your batteries. __ Designed by Richard Torrens

Battery Equal Charge Indicator  -  The circuit below illuminates an LED to indicate unequal charges between two 12 volt lead batteries.  It can be used to verify that two batteries are connected in parallel or isolated since the LED will be off when the voltages are equal within a tollerance, or on if the voltage difference is greater than 100 millivolts.  Three comparators __ Designed by Bill Bowden

Battery Low Voltage Beeper  -  This circuit provides an audible and visual low voltage warning for 12V battery powered devices.  Idle current: 6ma Low Voltage Warning current: 15ma. __ Designed by G. Forrest Cook

Battery Monitor also enables constant power boost converter  -  11/08/07 EDN-Design Ideas When powering a microcontroller directly from a battery, it is important to monitor the battery voltage to ensure system integrity __ Circuit Design by Rex Niven, Forty Trout Electronics, Eltham, Victoria, Australia

Battery Monitor Draws 8 ?A or Les  -  04/13/95 EDN-Design Ideas The battery monitor in Fig 1 nominally draws 5 ?A during normal operation and flashes an alarm indicator when the battery voltage drops below a critical value.  The alarm-state current depends on the desired indicator brightness, but you can easily make the current average less than 500 ?A.  This monitor was developed as a change-battery warning __ Circuit Design by Arthur W Du Rea Jr, Science Applications International Corp, Oak Ridge, TN

Battery Monitor Emulates Auto Dashboard  -  07/03/97 EDN-Design Ideas  When you use battery-powered scientific-recording equipment, you must know the state of the battery, because an unnoticed battery run-down can lead to loss of data.  Several types of warning indicators are available, but all have their drawbacks.  Moving-coil indicators, test terminals, and digital flags, for example, __ Circuit Design by TG Barnett and J Millar, University of London, UK

Battery Monitor for 12V Lead-Acid  -  This simple circuit makes it posible to monitor the charging process to a higher level.  If you need more information then check out the LM3914 Datasheet.   Final adjustsments are simple and the only thing needed is a digital voltmeter for the necessary accuracy __ Designed by Jan Hamer

Battery Monitor in Multiplecell Applications  -  APP 405: May 04, 2001-This App Notehows the reader how to use the Dallas SemiconductorUsing the DS2760 or DS2761 Battery Monitor in Multiple-Cell Applications __ Maxim Integrated

Battery Powered Lap Top Computer Power Supply  -  DN18 Design Notes__ Linear Technology/Analog Devices

Battery Simulator Has Variable ESR Response  -  03/18/10 EDN-Design Ideas This active circuit represents many battery types. __ Circuit Design by Barry Galvin, Grae LLC, Simi Valley, CA

Battery simulator provides current limiting  -  08/01/97 EDN-Design Ideas A constant-voltage active load can perform as a battery during the charge cycle.  You can set the load voltage from 5 to 35V by using potentiometer PV and thus can simulate batteries ranging from 6 to 32V. __ Circuit Design by HernĂ¡n Tacca, University of Buenos Aires, Argentina

Battery Tester for 1.5 & 9V  -  Schematic & Notes only, no description included. __ Designed by Martthew B

Battery Tester For Deaf And Blind Persons  -  Many blind and deaf-blind persons use portable electronic devices to assist their everyday lives but it is difficult for them to test the batteries used in this equipment.  Talking voltmeters are available but there is no equivalent usable by deaf-blind persons.  This battery tester uses vibration and a user-settable control to enable blind and deaf-blind|

Battery Voltage Monitor  -  R1 controls the trip-point of the circuit.  adjust it accordingly.  to reverse the logic   (have the led light up when the battery has at least X amount of power,) connect the led to ground through R4. __ Designed by Andy Wilson

Battery voltage Monitor using an LM358 op-amp  -  This circuit is used to monitor the battery voltage, using a bi-color LED to indicate the state of the battery.  When the LED is "GREEN" the battery voltage is above 11.9 volts.  When the LED is "YELLOW", the battery voltage is between 11.9 and 11.5 volts.  When the LED is "RED" the battery voltage is below 11.5 volts.  You can of course, modify the trigger points by using the trimmer resistors and/or changing the value of the dropping resistors in the divider. __ Designed by Steven Weber, KD1JV

Battery-Discharge Measurement Circuit  -  Battery-life measurement for a portable system is a time-consuming task and many methods used for it do not give reliable results.  Presented here is a circuit using which you can measure __ Electronics Projects for You

Battery-Level Indicator  -  Normally, in mobile phones, the battery level is shown in dot or bar form.  This lets you easily recognise the battery level.  Here we present a circuit that lets you know __ Electronics Projects for You

Battery-Low Indicator  -  Rechargeable batteries should not be discharged below a certain voltage level.  This lower voltage limit depends upon the type of the battery.  This simple circuit can be used for 12V batteries __ Electronics Projects for You

Battery-Monitor  -  A Very Simple circuit and some Variations.  Play with it.  All parts are cheap and should be easily obtained. __ Designed by G.L. Chemelec

Battery-Status Indicator Uses Two LEDs  -  08/12/10 EDN-Design Ideas Use LED brightness to indicate battery charge. __ Circuit Design by Abhijeet Deshpande, People?s Education Society Institute of Technology, Bangalore, India

Button Battery Cell Internal Resistance Measurement Circuit  -  The open cell voltage of a small silver oxide button cell battery remains very close to 1.5 volts over most of the life of the cell.  However, there is a relationship between battery health and the internal resistance of the cell.   This circuit when used. . . Circuit by David A. Johnson P.E.-July, 2006

Car Battery Failure Detector  -  A car battery deteriorates in use and its life seldom exceeds four years.  When new, its voltage may drop to only 2V while cranking the engine.  As the battery ages, its internal impedance increases and so the voltage drop while cranking also increases, until ultimately the drop is high enough to prevent the engine from|

Car Battery Monitor  -  Don't get caught with a flat battery.__ SiliconChip

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

Circuit disconnects loA - D  -  02/17/00  EDN-Design Ideas Placing a load-disconnect circuit on the output of a bootstrapped step-up regulator allows the regulator to start with load currents much higher than would otherwise be possible (Figure 1).  During shutdown, the disconnect completely isolates the battery __ Circuit Design by Larry Suppan

Circuit Disconnects Load From Battery  -  03/14/96 EDN-Design Ideas To prevent battery damage, the circuit in Figure 1 disconnects the load at a predetermined level of load voltage.  This load voltage, VTRIP, is closely proportional to the battery voltage.  R1 and R2 determine the level of VTRIP  that corresponds to voltage of 1.15V at pin 3 of IC1.  A voltage of 1.15V at pin 3 of IC1 causes the internal comparator to trip.  Thus, VTRIP=1.15(R1+R2)/R1 __ Circuit Design by Michael Keagy, Maxim Integrated Products, Sunnyvale, CA

Circuit Extends Battery Life  -  07/29/10  EDN-Design Ideas Using a relay, the circuit completely disconnects the batter during to eliminate power consumptiontwo previous Design Ideasdescribe simple ways to automatically disconnect a battery from its load after a preset on period, which extends battery life (r __ Circuit Design by Jos?M Esp? Rafael Garc?-Gil, and Jaime Castell? University of Valencia, Valencia, Spain

Circuit Monitors battery voltage  -  11/21/96 EDN-Design Ideas The circuit in Figure 1 monitors four NiCd rechargeable batteries and causes the LED to flash if the voltage of the batteries goes lower than 4V.  The circuit consumes only 8 mA of current under normal operating conditions.   IC1 is an eight-pin IC that includes an op amp, a comparator, and a 1.2V zener diode.  The zener diode connects to the negative input of the comparator in the IC as a reference.  R6 and R7 divide the battery voltage __ Circuit Design by Yongping Xia, Philips Lighting Electronics Co, Torrance, CA

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 __ Circuit Design by Ron Clark and Larry Suppan, Maxim Integrated Products

Circuit protects battery from overdischarge  -  04/12/01 EDN-Design Ideas All electronic circuits powered by a battery discharge the battery.  In some applications, it is undesirable to overdischarge the battery, because it could irreversibly reduce the battery?s capacity and the number of discharge/charge cycles.  The circuit in Figure 1 protectsPDF contains multiple circuits, scroll to find this circuit __ Circuit Design by Martin Wuzik, Implex AG Hearing Technology, Ismaning, Germany

Circuit Safely Deep Discharges NiCd Battery  -  NiCd batteries possess an undesirable memory effect caused by partial discharges.  The remedy is to do a complete discharge before charging again.  Figure 1 shows a simple circuit which performs this feat.  Although relatively straightforward in concept, the circuit has three redeeming features: 1) It is powered by the battery being discharged.2) After the battery is fully discharged current drain is only about 4 uA, usually well below the self-discharge of a battery alone.3) Near end-of-charge the LED flashes.9publised 04/29/99 EDN-Design Idea) __ Designed by Jim Hagerman, Science & Technology International, Honolulu, HI

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. __ Circuit Design by Jim Hagerman, Science & Technology International, Honolulu, HI

Configure a Low-Cost, 9V Battery-Voltage Monitor  -  27-Nov-08 EDN-Design Ideas You can configure an inexpensive, 9V battery-voltage monitor __ Circuit Design by Paul C Florian, McKinney, TX

Constant Voltage Load Tests Battery Chargers  -  04/11/96 EDN-Design Ideas Testing battery-charging circuits on an actual battery can be difficult, because battery voltage changes during the charging cycle.  The constant-voltage "load box" circuit in Figure 1 provIdeas a constant-voltage load for a battery-charger circuit independent of the amount of input current.  A constant-voltage load means that the circuit must have a low impedance at all frequencies.  The input impedance of this circuit is approximately 0 ohms at dc and 0.5 ohms at all reasonable input frequencies for charger applications. __ Circuit Design by Jon Dutra, Linear Technology Corp, Milpitas, CA

Digital Lock-In Milliohmmeter  -  A milliohmmeter is just the tool for checking trace resistance on a printed circuit board, tracking down shorted traces, and measuring the contact resistance of a switch or connector.  Its the kind of tool that would come in real handy occasionally, but not often enough to justify shelling out hundreds of dollars.  Wanting one anyway, I set out to make my own.  It turned out to be not only an exciting project, but a true adventure of discovery as it provided a window into the workings of lock-in amplifiers __ Designed by Dick Cappels

Digital RF Field Strength Indicator  -  Useful as a transmitter tune-up meter or an RF sniffer, this is an RF field strength indicator that is loosely based on the Broad Band RF Field Strength Probe, described elsewhere.  It detects RF via a square law detector, basically its a crystal set with gain.  The bias circuit for the detector is significantly modified from the probe to reduce the effects of battery voltage droop during use. __ Designed by Dick Cappels

Discharger for Receiver Battery Packs  -  You may have read about cycling NiCad batteries.  If not, read a little here (Red's R/C Battery Clinic) for an excellent overview.  Overcharging apparently leads to voltage depression, which can be corrected by one or two complete discharges (to 1 to 1.1 volts per cell).  On the other hand, over discharging the batteries to a low or zero voltage can damage them, and if the batteries have not been overcharged and have no voltage depression, cycling just uses up regular battery life.  I designed and use this discharger occasionally to remove voltage depression and insure battery capacity is still ok for those planes that have no low voltage alarm. __ Designed by Rob Crockett 8/3/98

Disconnect Load from Battery  -  03/14/96 EDN-Design Ideas To prevent battery damage, the circuit in Figure 1 disconnects the load at a predetermined level of load voltage.  This load voltage, VTRIP, is closely proportional to the battery voltage.  R1 and R2 determine the level of VTRIP  that corresponds to voltage of 1.15V at pin 3 of IC1.  A voltage of 1.15V at pin 3 of IC1 causes the internal comparator to trip.  Thus, VTRIP=1.15(R1+R2)/R1 __ Circuit Design by Michael Keagy, Maxim Integrated Products, Sunnyvale, CA

Dual Battery Power Manager Increases Run Time by 12% & Cuts Charge Time in Half  -  DN277 Design Notes __ Linear Technology/Analog Devices

Dual PS - U  -  This mini-project came about from building a garden shedI decided to use an old UPS battery and some spare halogen downlighters for illumination.  But as I researched lead-acid technology, I decided that I needed more sophisticated than a simple switch if I wanted the batteries to survive. __ Designed by Mark Hennessy

Expanded Scale 12v Battery Voltage Monitor  -  The circuit below expands the battery voltage monitoring scale for a 12v battery so a more accurate voltage reading can be made.  The numbers printed onto the face of a standard 0v to 5v meter are changed so the scale ranges from 10v to 15v.  http://archil. . . Circuit by David Johnson P.E.-October, 2005

Flat Battery Indicator  -  This small circuit was developed to monitor the battery in a model hovercraft.  The lift in the model is produced by an electric motor driving a fan.  To avoid the possibility of discharging the rechargeable battery pack too deeply, the design lights a conspicuous LED mounted on the model when a preset threshold voltage is|

Frequency Division Battery Detector   -  This simple circuit uses an ultrasonic sensor   (part # 255-400SR16) from Mouser electronics.  It amplifies the signal and then converts the ultrasonic frequency by digital division down to a human frequency.  The resulting sound at the headphones is a "buzz" when a bat calls nearby __ Contact: archilochus57 @ yahoo.com

Frequency Meter & Pulse Generator  -  Simplicity in circuitry was the design direction.  Zero mass (firmware only with no physical components) would the ultimate achievement.  This instrument doesn't have any front panel controls because the user interacts via an RS-232 terminal program at 9600 baud.  I needed a frequency meter for my experiments in Nondu, Thailand, where I really don't have room for a lot of instruments.  I wrote some straight forward code to read the 16 bit counter in the AT90S2313 after period of time, which was determined by running a timing loop.  By the way, I tried various approaches using interrupts from the 8 bit timer to set the counting interval, but found timing uncertainty resulted in intolerable jitter in the measurements, to as inelegant as it is, timing loops turned out the be give the best results.  The results of the counts are converted to ASCII and sent to the terminal.  After finishing the frequency meter, I realized that only half the Flash ROM was used and that I could fit a handy pulse generator program I found on the web into the same chip, but having two instruments in one.  The result is a combined counter and frequency meter.  The chip flips between the two programs, The only things common between the two programs is some initialization and some of the serial port I/O code.  The pulse generator firmware is pretty much as originally published, except that I modified it to drive a resistor network so as to allow the pulse output amplitude to be selectable. __ Designed by Dick Cappels

Fully Isolated Lithium Ion Battery Monitoring & Protection System   -  Launch the evaluation software and connect the USB cable from the PC to the USB mini-connector on the SDP-B board__ Analog Devices from the Lab

Battery Testers / Monitors:  #'s - A        B - F        G - L         M - R        S - Z

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