We had the Garmin unit until it blew away. It was formerly Nexus. Garmin support for it was horrible. The crap I went through after Garmin bought Nexus was just stupid. So after
Hurricane Harvey, we went back with Raymarine. As the rig had been pulled, we went wired. If you go wireless, don't go the
cheap option, step up and pay the
money. The problems we had with the Garmin unit were because of Garmin support, not the product.
Batteries DO have to be changed about every 2 years. They are a simple Duracell pair of
batteries. I still have TWO new ones, if anyone needs them for their Garmin/Nexus units. PM me your address and I'll give 'em to you.