NMEA and compass killing battery?

I Installed the NMEA and Lowrance compass this spring. My graphs come off when the is boat in storage.
Is the network draining my battery or do I need to start looking for other sources of trouble?

When I installed my NMEA network, I also installed a switch to prevent that parasitic drain as some of the others describe it; worked out well.

You should have a switch in line with the power node on the NMEA network.

Thanks guys.

Some network devices receive their power from the network power (such as the point one antenna). Best to use a switch. I installed a master switch and fuse panel for all my electronics up front stuff.