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csatt

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5Instructables13,144Views5CommentsCupertino, CA
I used to get paid for designing computer and networking hardware and software. Now I design stuff for fun and give it away.

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  • csatt commented on csatt's instructable ADS1115 InstESRE Pyranometer
    ADS1115 InstESRE Pyranometer

    This pyranometer is based on a kit from InstESRE (Dr David Brooks). I added the ADS1115 interface and temperature compensation. Dr Brooks would be the authority on the photodiode.My guess is that it would work, but it would need a different physical packaging. The resistor value might also have to be different.My recommendation is to get the kit from InstESRE which includes the PDB-C139 photodiode.

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  • csatt's instructable ADS1115 InstESRE Pyranometer's weekly stats:
    • ADS1115 InstESRE Pyranometer
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  • csatt commented on csatt's instructable ADS1115 InstESRE Pyranometer
    ADS1115 InstESRE Pyranometer

    Good point! I added two sentences at the very beginning that should help. Thanks for the comment.

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  • csatt's instructable IV Swinger 2 - PCB (PV Cell, EMR)'s weekly stats:
    • IV Swinger 2 - PCB (PV Cell, EMR)
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    • IV Swinger 2 - PCB (PV Module, SSR)
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      9 comments
    • IV Swinger 2 - PCB (PV Module, EMR)
      206 views
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  • IV Swinger 2 - PCB (PV Module, SSR)

    Looks like that YouTube link didn't work. Here is another try. If this doesn't work, you can find it by googling "iv swinger background youtube".https://youtu.be/xrC5VoMxGJM

    That would be the epitome of overkill (like this reply :-), but yes!Power is energy/time, and that is what you need to charge your battery. Power is measured in Watts, which are equal to Volts * Amps. Saying "9 volts of power" is incorrect. If current (I) is zero, the voltage (V) can be anything, and the power is still zero. Current only flows if there is some connection and (non-infinite) resistance (R). Ohm's Law says that V = I * R. An IV curve is a graph of the current (I) versus voltage (V) for the solar panel. That curve changes depending on how much sun is hitting the panel (and also on several other things such as temperature). But once you have an IV curve for a given set of conditions, you can calculate the power (I*V) for any point on that curve. You can also calcul...

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    That would be the epitome of overkill (like this reply :-), but yes!Power is energy/time, and that is what you need to charge your battery. Power is measured in Watts, which are equal to Volts * Amps. Saying "9 volts of power" is incorrect. If current (I) is zero, the voltage (V) can be anything, and the power is still zero. Current only flows if there is some connection and (non-infinite) resistance (R). Ohm's Law says that V = I * R. An IV curve is a graph of the current (I) versus voltage (V) for the solar panel. That curve changes depending on how much sun is hitting the panel (and also on several other things such as temperature). But once you have an IV curve for a given set of conditions, you can calculate the power (I*V) for any point on that curve. You can also calculate the resistance of the load for that point (V/I). Conversely, if you know the resistance of the load, you can find the point on the curve for that load, and therefore the power that is delivered to that load.In your case, the battery is the load. It is quite possible that IV curves of your solar panel would expose the problem. But you can measure the power (i.e. the rate of charging) with your meter. You need to measure the current as well as the voltage. A typical meter requires you to put the meter in series to measure current (e.g. between the solar panel and the battery). There should be more current when there is more sun hitting the panel. You can calculate power by multiplying the measured current times the measured voltage. If you know the rated power (Watts) of the solar panel, this could indicate if it is underperforming. The rated power is a "best case", so even half that value is probably good.Solar panels do lose efficiency as they age. But the most common reason for solar panels "underperforming" over time is that they are getting less sun. Do you have any trees that have gotten taller and are shading this panel more than they used to?I made a YouTube video a while ago in which I attempt to explain IV curves:At the beginning of that video, you can see a picture of the "grandfather" of the device in this Instructable.

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    • IV Swinger 2 - a $50 IV Curve Tracer
      323 views
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      1 comments