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Measuring the voltage of the solar panels


Miguel_____ Apr 6, 2022 07:11 PM

Hello!

These days one of my batteries started to fail and because of this I thought that it would be interesting not only to obtain the battery voltage but also to know the voltage of the solar panel itself and thus be able to analyze when it is charging and when not.

Programming the battery is simple, the command `Battery(BattV)` gives us the voltage. Is there something similar for solar panels?

Thank you very much!


smile Apr 8, 2022 10:36 AM

There are smart charge controllers from the CS that can give you (to logger) a lot of other information besides the battery voltage.

Alternatively, you can use resistive bridges also available from the CS to transform the voltage and current of a photovoltaic module into an analog signal compatible with the analog inputs of the logger.

With the availability of this additional data you can do many processing according to your specific needs

Smile


JDavis Apr 11, 2022 06:21 PM

VDIV10:1 is the voltage divider that would bring the voltage down into the range of datalogger analog inputs. If using the built in charger of a CR6, the charge voltage is available in the Status table.

Without the solar panel voltage, you can infer when it is working based on rising battery voltage. It takes a while for battery voltage to come up, and there can be bumps in the data from things like modems turning on and off. So, watching battery voltage is best on an extended time scale. Comparing current battery voltage to a saved value from 10-15 minutes ago could indicate if the battery is charging.

https://help.campbellsci.com/crbasic/cr1000x/#Instructions/tablenamefieldname.htm

Daily minimum battery voltage values are great to watch over time. They let you see downward trends that would indicate a solar panel that is undersized for the station.

How quickly battery voltages drop off at night after a sunny day is useful to see battery health problems. If things drop much steeper than when new, either something changed on the site to increase power usage or the battery is getting old.

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