I was wondering if there is a way to send the amount of charge left in a laptop's battery through usb to an arduino and display it on an LCD 16x2 , maybe some kind of script running in the background. Any ideas? I would appreciate the help
Most laptop batteries have 'fuel" gauges built into them Tryng to duplicate that information is difficult at best. The other real issue is the much higher voltage from such a battery. The regulator in an Arduino is a linear type and the extra voltage/energy is wasted as HEAT. It serves no useful purpose for the Arduino except to heat up the board. THe power Might be used for motors but there is also another much more serious side to this question. MOST ALL Laptop batteries are Li-Po batteries and that class of battery is VERY VERY Dangerous. An accidental short or improperly charging them isn't very healthy as they, when mistreated catch fire very frequently, If you are lucky, unlucky and they EXPLODE. Lithium BURNS very well in water... FACT, water will not extinguish a Lithium Fire. Not IMSHO a very good Idea at all. I own 8 0r 10 Li-Po cells and I will probably never use them unless I can find a reasonably safe way to use/charge them. Because of the VERY high energy density they are very attractive power sources, Even to me with 50 years in electronics... But I like things that are intrinsically safe and a laptop battery out of the protection of the Laptop is NOT intrinsically safe. This is probably the reason they don't sell hobbyist conversion packages for them from China too, along with everything else. IMO
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what i meant is showing the battery info from windows 7 to arduino through serial communication (to show the battery percentage shown near the clock. bottom-right ) . not to connect the arduino to laptop battery