question

mogul avatar image
mogul asked

MPPT 75/10 flashing green (2Hz)

Testing out a new MPPT 75/10 along with a small solar panel (3 pcs 6V/3W panels in series) and an used 80Ah AGM battery.

I notice that even after several days og sunshine and with not consumption, the green LED flashed twice a second to indicate BatteryLife.

Battery voltage is 13.0V - 13.2V.

Does this indicate a dead battery?

Or should I just add a propper solar panel to get things going?
What are good threshold values for an AGM battery?

batterylife
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3 Answers
Alexandra avatar image
Alexandra answered ·

@mogul

What does the app say?

VOC of the panels needs to be 5v above battery voltage for charging to start. So probably the panels are not good enough to get the charge started.

And the charge values for your battery are whatever the manufacturer recommends. 13v is not depleted usually for AGM.

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mogul avatar image
mogul answered ·

When the sun is shining the app says it is charging the battery with perhaps 0,5A. panel voltage is about 19V - 20V

To me it appears that the MPPT is working. I think my question is: "does the green flashing indicate a problem?"

Today the charger report that is has charged 20Wh, which in the expected range. 25% bulk and 75% float. I guess that's for making up for self discharge.

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mogul avatar image
mogul answered ·

ah yes, now the sun is down, charge current is 0A and the battery voltage has dropped to 12.8V. Green LED is still flashing, so I guess the charger is sipping a little juice from the battery to keep it self alive and kicking.

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