namezero111111
New Member
Hello folks,
I just registered for this forum.
I am trying to design a circuit to determine lead-acid battery charge level.
I determined that at 77*F, a 100% charge would be 12.63V, and a 50% charge would be 12.00v.
I also have data for every 10%.
I designed the circuit as indicated in the attached file, and have tested it in LTspice, which indicates that the circuit would work (see the second picture).
However, I believe that this circuit is very difficult to built (it seems cumbersome). I have read about the LM3914 (?) that can be used to drive a bar display, but I don't think it could measure such small voltage changes that are also non-linear.
So I was wondering, if I were to build this, is there any better way than using odd resistors like 6579 or 7353 ohms? I'd have to be very close to those values so that the bar display is reasonably accurate.
I've also seen designs where the voltage divider on the measured side is "cascaded" instead of every comparator having its own little voltage divider. If I were to make such a design, how would I calculate the values of the resistors required?
Do you see any problem with the design as is? I might be worried about the low current in the diodes as indicated on the diagram, would that be a problem?
Thank you all for your help in advance!
-namezero
I just registered for this forum.
I am trying to design a circuit to determine lead-acid battery charge level.
I determined that at 77*F, a 100% charge would be 12.63V, and a 50% charge would be 12.00v.
I also have data for every 10%.
I designed the circuit as indicated in the attached file, and have tested it in LTspice, which indicates that the circuit would work (see the second picture).
However, I believe that this circuit is very difficult to built (it seems cumbersome). I have read about the LM3914 (?) that can be used to drive a bar display, but I don't think it could measure such small voltage changes that are also non-linear.
So I was wondering, if I were to build this, is there any better way than using odd resistors like 6579 or 7353 ohms? I'd have to be very close to those values so that the bar display is reasonably accurate.
I've also seen designs where the voltage divider on the measured side is "cascaded" instead of every comparator having its own little voltage divider. If I were to make such a design, how would I calculate the values of the resistors required?
Do you see any problem with the design as is? I might be worried about the low current in the diodes as indicated on the diagram, would that be a problem?
Thank you all for your help in advance!
-namezero
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