I have a custom data logger attached to a sensor being powered by a solar panel(charge controller and battery). I have a problem where I'm getting 10 milliVolt one sided spikes in my ADC readings as seen in the picture below.
I only encounter this problem when my logger is powered by the charge controller and only when the solar panel is plugged into the charge controller at the same time. (When it is only a battery and the charge controller, or when I'm running my system off of wall power and an adapter this problem doesn't occur.)
I have tried adding an off the shelf input filter as well as a low pass with big capacitors on the power input of the data logger to try and solve this since it seems to be an input power issue but it seems to have no effect whatsoever. These spikes are prevalent on all my ADC channels as well, so its not just the sensor.
Does anyone have any idea as to how I might go about reducing these spikes?