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renewable energy data logging — Parallax Forums

renewable energy data logging

BullCreekBullCreek Posts: 3
edited 2005-12-11 05:58 in General Discussion
Hello,

I'm relatively new to the world of stamps, but bought a professional development board·a while back and have enjoyed playing around with several sample projects.· As my first real world project, I thought I might try to make a data logging device for my renewable energy system.· I got a real bargain on several old analog meters and 150-500amp/50mv shunts on eBay recently which further has spurred my interest.

I have solar and a wind turbine, and would like to log the following to a computer via serial or USB.

battery voltage (48v nominal bank)
amps into the battery from wind
amps into the battery from solar
amps in/out of the battery from/to inverters (the inverter is also a charger)

At first I thought this would be a simple ADC application, but then I realized that the shunts are only going to make -50 to 50mv - which is too small for accuracy with·any of the ADCs parallax sells.· I presume some sort of voltage amplifier would be needed - but unfortunately, I am a total analog newbie.· Thoughts (including telling me this is too advanced a project for a beginner)?·· Thanks in advance.· --B

Comments

  • SPENCESPENCE Posts: 204
    edited 2005-12-11 03:33
    I am not shouting. I have been able to read and type all caps much easier for over 55 years.

    Use a op amp to bring the shunt voltage up to usable level. Be careful of polarity. You may have to use a floating power supply, depending on where the shunt is located in the circuit. I "think" if you put it on the negitive terminal of the battery it sould eliminate the nead for a floating power supply for the op amp.

    I am planing to use the link-10 or e-meter for my system. Just found new kc125g for $565, which is $130 under other suppliers so far.

    I am using 12vdc and 6 t105 batteries from golf cart. Pm if you want to establish direct email. (from upstate south carolina)

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    73
    spence
    k4kep
  • ChrisPChrisP Posts: 136
    edited 2005-12-11 05:58
    Analog devices has a very nice instrumentation amplifier (AD620) comes in both soic and dip packages very precise, adjustable over a wide range and a very simple circuit, just supply and a gain resistor is enough to use it. I've used it to amplify a 20mv full scale signal to 5 volts and gotten excellent accuracy.



    Chris
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