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5Instructables7,280Views3CommentsCupertino, CAJoined March 24th, 2017
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's instructable IV Swinger 2 - PCB (PV Cell, EMR)'s weekly stats: 12 days ago
    • IV Swinger 2 - PCB (PV Cell, EMR)
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  • csatt's instructable IV Swinger 2 - PCB (PV Module, SSR)'s weekly stats: 4 weeks ago
    • IV Swinger 2 - PCB (PV Module, SSR)
      1,197 views
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      9 comments
  • csatt's instructable IV Swinger 2 - PCB (PV Module, EMR)'s weekly stats: 4 weeks ago
    • IV Swinger 2 - PCB (PV Module, EMR)
      206 views
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  • csatt commented on csatt's instructable IV Swinger 2 - PCB (PV Module, SSR)5 weeks ago
    IV Swinger 2 - PCB (PV Module, SSR)

    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.

    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

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  • csatt's instructable IV Swinger 2 - a $50 IV Curve Tracer's weekly stats: 1 year ago
    • IV Swinger 2 - a $50 IV Curve Tracer
      323 views
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      1 comments