How to measure surplus solar array output

[tcvt]

Hello,

With the days getting longer, my batteries spend much of their time in float.  There is extra capacity in the solar array not being used this time of year.  Is there a way to determine how much unused solar capacity is available?  This would be useful information since I'm now thinking of replacing the propane refrigerator with an electric one.  Maybe this can be added as a feature in the firmware if it is possible for the charge controller to periodically calculate the difference between power available at the input from what is being drawn at the output. 

Tom

[niel]

excess in summer being used could translate to a shortage in the winter.

that said, you can get a rough idea just by how long the pvs maintain a float charge and it will probably end its charge close to that time. keep in mind that the current would back off all of the way until sunset so you don't have full output until sunset just like you don't have full output at sunrise. add to that any differences such as a brief shading could downgrade the output further.

nobody can accurately state what you would have as it is a guess to a point just like it is a guess as to how much power one will use daily.

[toothy]

Hello Tom

Here is my sort of simple snapshot way of determining what is wasting away in the panels.

On a sunny day after you hit float see how many watts the controller is putting out to hold float.
Hit EQ and note the output from controller, subtract float from EQ and there you have an instantaneous measurement, barring clouds and such. Don't forget to put it back in float.

Wade