Join Date: May 2008
Location: Colo Springs, Colorado
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Simple 4 Led visual voltage level for 12V battery from Radio Shack's "Getting Started in Electronics".
Nowadays you can usually get a digital volt meter for less than $5 so it's hardly worth the trouble of building this unless maybe you want it incorporated permanently into the bike as a voltage level indicator.
Lower 2 LED's could be red, 3rd yellow, 4th green, for full charge. You would have to calibrate it with a voltmeter to set off LED's at proper voltage points. Haven't checked lately but Digikey probably has this as a single "all-in-one" chip now.
Last edited by wernmax; 05-16-09 at 11:24 PM.