LM339 Voltage indicator

Thread Starter

iONic

Joined Nov 16, 2007
1,662
SGT,
Thanks for the help. I will definitely use a circuit as this in the future. But with the complexity of parts and tuning, many of which I would have to purchase I am thinking of another path to success. I have come up with a different plan. With your original suggestion of monitoring both batteries separately I thought that the old LM3914 would be ideal and easy to implement. It may take a few more LED's, but lord know I have plenty of them, as well as all the other necessary parts.
I'd have one bar of LED's for each LM3914, thus can monitor very accurately each battery. I could monitor between 11V and 14V in 0.5V increments with only 7 LED's per battery.

What do you think?
 

SgtWookie

Joined Jul 17, 2007
22,230
You would reduce your parts count very significantly.
If you used a 10-segment bar display, you would further reduce your parts count while enabling increased resolution.

You could go from 10.4v to 14v in increments of 0.4v. 14v would indicate that your battery was being charged heavily. 13.6 would be a good "float" voltage - depending upon temperature, of course. 12.4 would be your suphation warning voltage. 11.6 would be your "must recharge" voltage. An indication of 10.4v after charging would mean a dead cell.

It was Audioguru who suggested the LM3914 early on, and I agree with his suggestion; however it would've been difficult to meet your original voltage monitoring requirements using one.

Using highly integrated circuits like an LM3914 will not only simplify your wiring, but the result will be more reliable due to the reduced parts count; simply, there is much less to go wrong.
 
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