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AA NiMH Battery Plotter Using Ubuntu — Parallax Forums

AA NiMH Battery Plotter Using Ubuntu

chiqueschiques Posts: 21
edited 2011-01-20 01:05 in Robotics
I have many rechargeable 'AA' batteries that I use around the house and some have been a bit flaky lately . I purchased some Japanese made Panasonic's over 10 years ago and the performance have slowly been degrating over the years. I am very impressed on the longivity of these cells but I really wanted to label the batteries which were acting as resistors in some of my devices. I read up on the ADC of the Web-BasicAnalogDigital-v1.4.pdf document and decided to build a rig that would check the voltage of my batteries as I loaded them across a ceramic .1 Ohm resistor. Here are the plots, now I can tell which batteries to weed out.

Oh yeah, I did this all in Ubuntu 10.04

Apps Used:

-Open Office Spreadsheet
-Minicom
-gedit text editer
-BS2 Board
-ADC08318-Bit Serial I/O A/D Converters with Multiplexer Options
-Bstamp Tokenizer (http://bstamp.sourceforge.net)


AA-NiMh-results.png
AA-NiMh-results.png
1010 x 393 - 34K

Comments

  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2011-01-16 16:41
    Does fast discharge through a 100 mOhm load really give an accurate comparison of battery lives under a normal load?

    -Phil
  • chiqueschiques Posts: 21
    edited 2011-01-16 17:47
    Phil Pilgrim (PhiPi) wrote: »
    Does fast discharge through a 100 mOhm load really give an accurate comparison of battery lives under a normal load?

    -Phil

    Hi Phil,
    Probably not, but at least I know which batteries are not preforming equally under an intense load. I figure a 100-1000K Ohm resistor for 24 hours would be a more accurate representation. But then again, I'd be testing batteries all week.

    I guess you can say this test doesn't give an accurate representation of 'how long' the charge is held (due to leakage and other chemistry breakdowns within the battery).
  • Clock LoopClock Loop Posts: 2,069
    edited 2011-01-17 05:17
    Perhaps the COMPLETED part of forum posts in the projects forum should be limited to moderators?

    Because this post is in NO WAY a complete project, evidenced by the lack of code, and/or schematics.

    I am not trying to attack chiques, this is just me showing an example of a situation where a post is in fact not worthy of the completed title.
  • bsnutbsnut Posts: 521
    edited 2011-01-17 13:06
    I agree with Clock Loop on this. Schematics, code and photos would show your great project that you did and I am, interested in doing something like this as well. Showing what you did would help the rest of us.
  • HumanoidoHumanoido Posts: 5,770
    edited 2011-01-20 01:05
    Please post code, schematics and details. I would like to plot batteries too. To drain batteries under simulated load, I take the load value that needs to be simulated, and then use ohms law to determine the resistance. Then I load up the battery with the resistor and measure the battery performance. I have a home-built resistor substitution box to dial in ohms resistance that helps with this process. Frequently batteries are proportionally spent but appear relatively fine without loading.
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