battery indicator


Car Voltage Gauge

The Car Voltage Gauge is based on 3 parts. The input circuit is an Analog to Digital Converter (IC2 CA3162E). The purpose of this chip is to sample an analog voltage and convert it to a decimal value which is read by a Display/Decoder Driver (IC1 CA3161E). This chip will turn each seven segment display […]


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 […]


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 […]


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 […]



Low Cost Battery Condition Indicator

This design combines power-on and low-battery indication, can operate with any battery voltage up to 15V, has very low current drain (2mA or less) and costs less than $3.50 with new parts. When the battery voltage is above a predetermined minimum, power on is indicated by what appears to be a steadily lit LED. In […]