battery life indicator

Do we assume it's a lemon + copper & iron nail battery bank?

Needs more lemons ;) Current over time might be a goer?

Best to weigh it. Compare full and empty values. Place battery on scale or strain gauge

Put a voltmeter on it. When it reads zero - no life.

...It's dead, Jim.

Our you could measure current and time, multiply, and accumulate (integrate).

Need more information on battery chemistry and topology. Different types will have different discharge characteristics.

And even in the best of cases, you should expect bothersome differences due to part-to-part variations, temperature, and usage history.

Possible useful paper.

A universal state-of-charge algorithm for batteries.pdf Bingjun Xiao Yiyu Shi Lei He Electrical Engineering Dept., University of California, Los Angeles Los Angeles, California, 90095, U.S.

Regards

Gerhard van den Berg

Gerhard, Is there a URL/link to that paper, or is it only available thru the University? ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |

Just write the author for a copy. I checked the UCLA site (and a few others) for a copy. Here is the web address for the UCLA list of conference papers:

In there, look for C141. That's the one. Often, they include a link to a PDF file. But in this case, no.

I'd just write the author at UCLA and ask.

Jon

Will do. Thanks! ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |

..

=A0 =A0...Jim Thompson

Thanks for the link.

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Sorry Ii had probelms with connectivity to my current news server, especially posting. I hope this posting attempt do work. Some of my postings took up to 24 hours to appear.

The paper is available at

and slect ACM digital libary Then search for "state-of-charge". It should be the first paper in the list.

You might have to subscribe and pay for the download the paper.

Gerhard van den Berg

Received your E-mail. Thanks! ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |

That's true. Although the site allows just about anyone to create a web account, that alone isn't enough to receive the article. A straight purchase of the article is then US$15.

I gather it can be accessed with either a SIGDA membership at US$25 and/or a subscription to the ACM Digital Library (which itself requires US$198, with US$99 for a professional membership and another US$99 for the ACM Digital Library subscription.) But unless there's another reason for those, it is hard to see why the extra money should be spent.

Although it may not be as quick at hand, it's often good enough to just write and ask for a copy from one of the authors.

Jon

I've seen this done before. Not a trivial circuit (you'd need a processor of some kind), but definitely doable. :-)

Cheers! Rich

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What do you mean by "after every usage:?

rate).

...or a battery "gas gauge". Simple and cheap enough to put into the batteries themselves. ;-)