Measuring battery capacity

omgitsaliv55

Hi everyone. I am still a noob at this stuff but nevertheless I'm still very interested and willing to learn. I've been working with the BoeBot for about a year now and have had a great experience. I had an idea for a "self sustaining robot". Its still in the works, but before I go ahead and lay down any plans, does anybody know a fairly easy way to measure the remaining battery life on the boe bot (or at least tell when its getting to critical levels)? I was thinking maybe analyzing capacitor discharge times...maybe I'm completely wrong. I played around with it and didn't get good results. Then again I'm a noob. Is there a chip I need to purchase? Any help is strongly appreciated. Thanks!

-Patrick

Mike Green

Look at www.emesystems.com. There's a note on measuring the power supply voltage using the RCTIME statement. The main problem is that the voltage doesn't change a lot between the initial drop from fully charged and the point where it declines precipitously just before going dead. This is true for NiCd and NiMH rechargables. Lead-Acid batteries have a much better (easier to predict) discharge curve. Do some research on the Wikipedia on the different battery types. You may be able to find characteristic discharge curves for each of the battery chemistries.