I'm working on an off-grid solar system for work that is going to power some measurement equipment. It consists of 6 240W solar panels, a 60 amp Morningstar MPPT charge controller, an Outback 2.5 kW inverter and a 24 volt, 1820 Ah battery. To keep tabs on the system, we have installed a datalogger with remote communication that sends data via email three times a day. We only have four analog channels and are measuring battery voltage, battery temp, solar charge current, and inverter current. The logger works fine except the inverter current reading fluctuates between 0 and 20 amps with an actual steady load of 10 amps. We are using a 100A hall effect current sensor (offers a higher output voltage than a shunt) and the voltage output reads perfectly steady on a DMM. Today I put a scope on, and found a ripple on the signal, about 300 mV peak to peak (signal is around 2.6 VDC or so), approx 120 Hz. The solar current signal is perfectly smooth so I know it's not the power supply for the hall sensors. I am assuming this ripple is caused by the inverter and the logger's sampling frequency must almost match the 120 Hz or some multiple.
Does anyone have any suggestions on how to remove this ripple? I tried a small cap today and it helped a bit, but I'm afraid of damaging the hall sensor if I go too big on the cap.