I saw on another forum that an owner of a TZT BB has to send his unit to the factory to have a regular, expected lithium battery replacement done after 3 years of use, or pay to have an electrician come to the boat to disassemble the unit and solder a new battery onto the board. Highly inconvenient to say the least. Is the situation the same for the TZT2? I don't find any reference to this in the manual but checking here to confirm if I can expect a similar low battery message on my monitor a year or so from now. And if TZT2 doesn't have this problem, what powers the internal clock during "power off" condition?