Helix 7

I have two Helix 7s, one at console, one at bow. I’m having Livescope installed as I type, it will run on a Garmin 93sv. The trolling motor is an Ultrex with built in transducer. My question is this: Do I need an SD card in the Helix units to store way points so that I can find them again ? If so, what size card ? I’m woefully ignorant about all this “new to me” tech so any help will be appreciated.

I have a Helix 7.
It stores waypoints on the hard drive of the unit.
I do back up my waypoints to an SD card.

I then use GPS Babel or other GPS converter program to back them up further in Google Earth Pro (also free)
I then use GPS Babel or other GPS converter program to translate the waypoints again into Lowrance format and upload them to my Lowrance units
I run both Lowrance and Humminbird.

Thanks CCTX, I bought this boat used, and the units came with it, so I’m trying to make the most of what I have already. Too much $$ to change out all the electronics at one time ! I’m watching tutorials on YouTube trying to figure them out but being a sledgehammer and crowbar type of guy, it ain’t easy !