As you are getting the LR you can set 80% in the car, or app. If it was the SR you cannot set either (and there is nothing to really be gained as the SR is an LPF battery that has no problem being charged to 100% every time). You cannot set the 80% limit in the Zappi, only in the car or app. You can set the timer in the Zappi if required, or set it to use the electricity from solar panels, or a mixture of solar panel backed up by the grid if the solar input drops below that required by the car or zappi settings.
If you search the site using "zappi" (search function is top right) you will get all the info you need...and more.