I think I have finally banished the error 20 code from my Xantrex remote. In the past I thought it was from poor quality shore power and I thought I had updated the firmware but I again got an error 20 code on my xantrex remote. I was wrong on both counts. I finally went all in, and updated the firmware on the inverter/charger, the remote and the communications firmware. I didn’t get an error 20 code on my most recent trip. In case it helps, I downloaded the firmware on a PC not an apple. My previous attempts with downloading the firmware to an apple did not successfully update the firmware. I also downloaded and updated each of the three firmwares to the usb drive separately, deleting each one after each was installed. Attempting to download and install all of them together didn’t work for me.
To answer your question above, I have never decreased the charge current directly, but have decreased the breaker rating from 25 to 20 or 15 amps depending on my shore power source. This indirectly lowers the charge current.