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More  Battery Monitors    Indicators

Lead-acid Battery Low Voltage Indicator 



Lead-acid batteries should not be discharged below a certain voltage.  Discharging a cell below about 1.8v and can often damage it, which will result in a lower Amp-hour capacity.  Large battery banks are critical in off-grid energy storage systems.  One bad cell in a series wired string will weaken the whole bank.  The circuits below are designed to be connected across either a single 2 volt cell or a 6v three cell battery bank.  It will alert the user of a weak cell by turning on a red LED when the cell voltages drop below 1.8v.  The circuit takes advantage of a low voltage LMP2231 op Amp from Nation Semiconductor and a LM385 voltage reference in the first circuit. In that circuit the red LED must have a forward voltage of about 1.6v at 5ma, in order to operate properly.  In the second three cell bank circuit, a TLV3701 voltage comparator is used.  The circuits are simple enough that they could be placed on a postage stamp size circuit board. 

2v Lead-acid Cell
 
6v Lead Acid Battery
 

Click on Drawing Below to view PDF version of Schematic

Lead Acid Battery Low Voltage Indicator Circuit

More  Battery Monitors    Indicators

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