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nods avatar image
nods asked

Smart Solar 75/15 charging issues


screenshot-20230102-125008.pngHi there...can anybody explain this repetitive charging wobble I noticed today that occured exactly every 9 minutes. I include 2 screenshots. The first an overview and the second zooming in on the wobble. Needless to say there was nothing obstructing the panel, full sunshine with no cloud, no aircraft and load disconnected etc. The large singular momentary dip on the overview shot was the one legged seagull arriving for breakfast!

Any thoughts?screenshot-20230102-104216.pngImage Caption


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ingo21 avatar image ingo21 commented ·
what is the voltage doing when the wobble is there.

at which charging state is your battery at this moment?


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nods avatar image nods ingo21 commented ·
The voltage only varies a small amount to reflect the change in solar input as normal. The soc was about 70% as we have not had much sun the last 6 days.
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nods avatar image nods nods commented ·
Battery was still in bulk phase of charge
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1 Answer
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klim8skeptic answered ·

Perfectly normal for the mppt to do a scan every 10 minutes or so, searching for a higher power output.

The mppt adjusts its power output by varying the current it draws from the array.

A trends graph of the pv voltage and current will show the current being increased and decreased while searching for a higher output. The pv voltage bounces up and down in response to the varying current.

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