I'm testing out a new Victron 100/30 solar charge controller, and I'm confused about the wattage readings I'm getting. The Victron app shows 54 watts (27.5V and 2.0A), but when I measure with a multimeter at both the solar panel and the MPPT terminals, I'm getting 28V and 3.8A, which calculates to about 106 watts. The app indicates that the battery is in float mode. Is the app measuring the watts being put into the battery or what's generated by the panel? It seems like the app's numbers could make sense if it's recording what's being sent to the battery, but I'm puzzled if it's supposed to show the panel output.
8 Answers
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It sounds like you're experiencing a common scenario. The controller's output is often limited to what the battery needs. If your battery is mostly charged, the controller will limit the input power to avoid overcharging. Try testing with a battery that’s around 50% charged to see if the wattage changes. That should give you a clearer picture.
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That makes sense. I wasn't sure if my battery was too charged. I also unplugged the panel and ran my fridge to drain the battery a bit for better measurements.