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Current and voltage measurement — Parallax Forums

Current and voltage measurement

Chris DunnChris Dunn Posts: 5
edited 2005-09-09 15:08 in BASIC Stamp
What is the best way to measure both voltage and current with a stamp? What I am looking to do is monitor a RV battery. Are there any website’s that have info on setting this up?

Chris

Comments

  • Bruce BatesBruce Bates Posts: 3,045
    edited 2005-09-06 06:19
    Chris -

    Although the link below references a multiple battery setup in an electric vehicle, the basic principles remain the same. Here is the link:
    http://genki.home.ionet.net/BattMon/BattMonArticle.html

    Essentially you will be measuring the battery voltage directly through one ADC, and the battery load (current draw) will be measured through a shunt with another ADC. Add an RTC (real time clock) if you choose to, and you can then calculate ampere-hours of discharge, if that's of interest to you. That should permit you to determine the "battery life left" in a no re-charge, constant drain situation. Use an LCD rather than a bar graph as used in the example, and you can display: present voltage, present current draw, and estimated % remaining battery life either sequentially, or through the press of a button.


    Regards,

    Bruce Bates
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-09-06 14:57
    Bruce,

    ·· Thanks for the link.· At first glance I wasn't sure it was anything interesting.· But once I got into it, I found I couldn't stop reading.· A lot of hard work went into that project, as well as some thinking!

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Chris DunnChris Dunn Posts: 5
    edited 2005-09-06 16:42
    Thank you for the site, great info on the voltage side. I have been looking for more shunt info, so far i have found alot of info on the montoring side. Does anyone know if Digikey or Jameco carries 30 and/or 15 amp shunts. I have search their sites with no luck, but then again, maybe there is a key phrase or a different name i should be looking for.

    Chris
  • TonyTTonyT Posts: 2
    edited 2005-09-09 15:08
    Chris,
    I have purchased several 50amp shunts at All Elec Corp for < $15.00. They carry shunts from 25 through 600 amp. Site located at:
    http://www.allelectronics.com/cgi-bin/category.cgi?category=385&type=store

    Alternatively, the Alt Energy Store for solar power is also a very good source for shunts, boxes, cables, etc. Site located at:
    Shunts: http://search.altenergystore.com/search?p=Q&ts=custom&w=Shunts&x=8&y=11
    Circuit breakers & acc: http://shop.altenergystore.com/items~Cname~Fuses,Cables,Switches+&+Misc.+Electrical~Cc~ELECSAFE~Bc~.htm

    Thanks
    Tony Thorne
    tthorne@camano.net
    tonyt@solarpowertracker.com
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