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Need help on how to build a Remaining Battery Charge/Life LED Meter? Answered

I've been searching for months now for an Instructable or step by step guide on how to make a remaining battery charge meter. If anyone can help i would greatly appreciate it : ) Ps: i have included a very poorly drawn diagram of what I'm seeing in my head. Gotta love paint.


here it is :)

Screen Shot 2012-01-25 at 5.08.21 PM.png

this bar graph driver circuit was taken off it's datasheet hope it helps


10 years ago

It ranges from "difficult" to "very difficult" depending o type of battery. Which is why the battery gauges in many pieces of electronics gear are so often annoyingly inaccurate. (the reason WHY it's hard is because the "discharge curve" of a battery - the plot of anything you can measure externally (say, voltage) vs the amount of usable energy actually left in the battery is very non-linear. The more complex "battery meter" circuits actually keep track of how much power you use, and subtract that from the amount of power they think the battery had when it was full, rather than just measuring a static value.