I have two circuits atto show what I am thinking. I am trying to make a lead acid charging temperature monitor. The circuits are from existing url's that I found by searching Google. My question is repeated on the page as follows: I want to set up a temperature monitor for charging lead acid batteries. I think the sensor can be imbedded into the negative battery post. Distance from the sensor to a LED indicator would be around 15 feet. I don't think there is a need to have exact temperatures. Likely a range within 10 degrees will suffice.
I would like to have the output from the temperature sensor light up a red LED when the temperature exceeds 130° Fahrenheit in place of the voltmeter in the first circuit (1). Since the first circuit is supposed to scale the output and provide 10 mV/degree, could a proper comparator circuit be made to indicate when the voltage exceeds 1300 mV or 1.3V? (Circuit B)
I have no clue how to calculate what resistor values would be needed in the comparator circuit (2). I am assuming there will need to be a trimmer to vary when the LED would turn on, maybe at V - REFERENCE? Would I need to supply the comparator voltage from a different source and what would that be?
Any help is certainly appreciated; Don