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Battery Monitors /Testers

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

Last Updated: October 18, 2017 05:04 AM

Circuits Designed by Dave Johnson, P.E. :

3 Volt Low Battery Voltage Flasher -  This circuit is designed to monitor two alkaline cells   (3v) that form the battery often used in portable electronic equipment. . . Circuit by Dave Johnson P.E.-January, 1998

6v NMH/NiCd Battery Tester -  I designed this circuit to test rechargeable six volt battery packs under constant current conditions.  As designed, the circuit applies a 10 amp load to the battery pack.  A heat sink must be used on the main power transistor. . . Circuit by David Johnson P.E.-December, 2004


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

1.5v Battery Meter -  simple but effective way of testing 1.5 volt cells __ Contact: P. Townshend EduTek Ltd

12 Volt Battery Charge 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.

12 Volt Battery Low Indicator LM741 -  Plans for a battery low indicator for a 12 Volt battery using an LM741 operational amplifier. __ Designed by REUK-Renewable Energy UK website

12 volt battery Monitor -  R1 controls the trip-point of the circuit.  when the voltage falls below the trip-point, the led lights.  adjust it to the desired level. __ Designed by Andy Wilson

12 Volt Lead Acid Battery Monitor -  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. __ Designed by Jan Hamer

12/24V Intelligent Solar Power Battery Charger. -  Don't cook your batteries by connecting them directly to a solar panel.  This charger turns off the power when the battery is charged. __ SiliconChip

12V battery level indicator for car batteries -  This kit measures battery voltage.  The red LED   (closest to the IC) indicates a low status11.5Volts or less.  The yellow LED indicates 50% charge12.0V.  The green LED indicates 12.6V or full charge.  This kit also measures the charging status.  Turn the charging system onor start the vehicle. __ CdS Electronic

12v Battery Voltage Monitor-Expanded Scale  -  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 . . . Hobby Circuit designed by Dave Johnson P.E.-October, 2005

12V Lead-Acid Battery Monitor using LM3914 -  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.  Connect an input voltage of 12.65 volt between the positive and negative poles and adjust the 10K trimmer potentiometer until Led 10 lights up.  Lower the voltage and in sequence all other Led's will light up.  Check that Led 1 lights up at approximately 11.89 volts. __ Designed by with permission of Jan Hamer

3 Volt Low Battery Voltage Flasher -  This circuit is designed to monitor two alkaline cells   (3v) that form the battery often used in portable electronic equipment. . . Circuit by Dave Johnson P.E.-January, 1998

300 MHz  Prescaler & 30 MHz preamp for Little More Serious Frequency Meter  -  A preamp that drives the CMOS counter input and a divide by 10 prescaler to extend the range __ Designed by Dick Cappels

6v NMH/NiCd Battery Tester -  I designed this circuit to test rechargeable six volt battery packs under constant current conditions.  As designed, the circuit applies a 10 amp load to the battery pack.  A heat sink must be used on the main power transistor. . . Circuit by David Johnson P.E.-December, 2004

9v Battery Voltage Monitor -  This circuit turns on a LED whenever the voltage of a standard 9v battery connected to the circuit drops below 7.2 volts.  It uses a LTC1440 comparator, which also contains a 1.18v reference diode.  In standby mode, the circuit draws only 4uA. . . Circuit by David A. Johnson P.E.-July, 2006

A 12/24V Intelligent Solar Power Battery Charger. -  Don't cook your batteries by connecting them directly to a solar panel.  This charger turns off the power when the battery is charged.__ SiliconChip

A 300 MHz  Prescaler & 30 MHz preamp for a Little More Serious Frequency Meter  -  A preamp that drives the CMOS counter input and a divide by 10 prescaler to extend the range __ Designed by Dick Cappels

A Battery Powered Lap Top Computer Power Supply -  DN18 Design Notes __ Linear Technology/Analog Devices

A 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

A Little More Serious Frequency Meter -  Maximum input frequency is specified to be 30 MHz in the multi-chip configuration, and in single-chip configuration, there are both 5 MHz and 10 Mhz versions operating with 10 and 20 MHz crystals, respectively.  All versions have 9 1/2 digit resolution.  I haveused __ Designed by Dick Cappels

A Low Battery Cutoff -  Also acts as a Master On / Off Switch.  NOW, Also a New P-Mos Version.  Supplies Positive voltage to grounded devices. __ Designed by G.L. Chemelec

A Precision Portable Voltage Reference -  It has been said that a man with one watch knows what time it is, but a man with two watches is never sure.    The same can be said for a person who has more than one voltmeter.    In my situation, I have several voltmeters in each of two different locations a third of the way around the world apart.  The best solution would be to send the meters to  NIST traceable calibration labs, __ Designed by Dick Cappels

A Pretty Good LC Meter Based on an AVR ATtiny2313, AT90S2315 -  Calculates and displays L and C from oscillation frequency using reference components.  No relays, no range switching, a minimum of controls.  And it is pretty accurate too! __ Designed by Dick Cappels

A Robust, Low Power, Battery Monitoring Front End  -  To program the board with the PC, install the evaluation software.  To do this, load the evaluation software by placing the CN-0253 evaluation software CD in the CD drive of the PC.  Using My Computer, locate the drive that contains the evaluation software CD and open the Readme file and follow the instructions for installing and using the evaluation software.  , Functional Block Diagram of Test Setup Figure 4 shows the test setup functional block diagram__ Analog Devices from the Lab

AC Current Probe for Oscilloscope Use -  I needed several current probes when designing the deflection circuits and high voltage supply for a computer display monitor, and the lab in which I was consulting only had one current probe, which I shared with the other four engineers on the project.  We did not really have a budget for test equipment on that project.  Designing the deflection circuit included designing several inductors, a current transformer among them.  It was merely a small diversion to design and put together a couple of simple current probes so I could, for example.  simultaneously watch the base current and the collector current of switching transistors.  The probe described here was designed to be used over the range of several tens of Hz to a couple MHz with currents from a few tens of milliamps to about 10 amps peak-to-peak.  Formulae are give which will allow you to create a design suitable for your own applications. __ Designed by Dick Cappels

Active Load Draws Constant Battery Power -  04/13/00 EDN-Design Ideas Unlike nickel-metal-hydride and lithium-ion rechargeable batteries, the discharge voltage of alkaline batteries is not constant and tends to vary from 1.5 to 0.8V per cell.  Alkaline-battery manufacturers specify the discharge life of their batteries under constant powerloads.  Because of the varying discharge voltage, you can't simply connect a load resistor to the cells to verify or measure power profiles without incurring a lot of error in your measurements.  The circuit in Figure 1draws a constant power from the battery pack.  Thus, as the battery voltage decreases, the load current increases.  A single potentiometer allows a user to set the desired wattage draw.  The circuit is simple and inexpensive to build. __ Circuit Design by Doug Farra

Alkaline Low Battery Voltage Indicator -  In many battery powered systems a user would like to know when it was time to replace the batteries  before they were completely discharged, causing the device being powered to fail completely.  Alkaline batteries have an open cell voltage of about 1.5 volts.  As they are discharged, the voltage slowly drops.  When the cell voltage reaches about 1.25v, they have delivered about 90% of their stored energy. . . Circuit by David Johnson P.E.-June, 2012

An RF Field Strength Meter using a Biased Schottky Deterctor and  a Moving Coil Meter -  A temperature compensated Schottky diode is used in an amplified, untuned field strength indicator that is powered by two AA cells idicates the relative field strength of  RF fields from a few kHz into the microwave region. __ Designed by Dick Cappels

Analog is Accurate Battery Fuel Gauge -  Circuit acts as a fuel monitor for a rechargable battery, typically NiCd or NiMH chemistries.  Analog type needle output meter appears like an automobile gas gauge. __ Designed by Jim Haggerman, Hagerman Technology LLC

Automatic Power-Off Saves Battery -  12/19/96 EDN-Design Ideas The Basic training program in Listing 1  helps visually handicapped people easily learn Braille dot code with the help of a trainer.  The trainer generates six-pin Braille code using six solenoids operating on an LPT1/2 either by directly connecting the low-power solenoids to the data bits of the parallel port or by driving solenoid pins  (pull-out type] using an UN2003 power driver  (Figure 1).  Push-in type solenoids require complemented  (0 for 1 and 1 for 0] Braille-code data bits or an extra inverter on the LPT1 port __ Circuit Design by Jose Carlos Cossio, Santander, Spain


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

 


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