(The lowest cost model of the Meridian line. Other units NOT affected by the following are the GOLD and PLATINUM)
A limitation that potential buyers should understand
Summary
If you allow the batteries in your Meridian GPS (basic model only, NOT the GOLD or PLATINUM models which DO NOT have this problem), to go DEAD without turning the unit OFF MANUALLY before the batteries are exhausted, then it is possible you will lose any waypoint, tracklog or route data or other information you have put into the unit since your last "power off".
What happens
There is the possibility that a user could lose data in a low battery situation. Within the Meridian family, this problem only exists ONLY within Meridian GPS model. The other Meridians units (GOLD and PLATINUM) DO NOT have this issue. The Meridian GPS is Magellan's lowest cost version of the Meridian family. In order to offer it at the current pricing, Magellan designed it such that both the software and user data shares the same memory chips. This creates one limitation: You cannot save user data to the non-volatile memory until the device is shut down by the user. In the interim, data is saved in RAM.
So, if a user saves some waypoints and creates routes, or whatever, these are not finally saved in non-volatile space until he turns the receiver off. After that, the data is saved indefinitely. The limiting situation occurs when the user saves data, but then does not turn the receiver off himself. If instead, he lets the batteries rundown to exhaustion and the unit turns itself off then data may be lost. In order to get the maximum battery life out of a GPS receiver, Magellan chose to let the voltage run down to a critical threshold where we have no time left to save user data consistently without corruption (because it takes more current to SAVE data than it does to just "receive and log" is my guess).
To avoid this situation when using the Meridian Basic GPS, the user can make sure that his important data is saved such that he won't lose it by simply cycling power himself prior to battery exhaustion. Data will be saved (when the power is shut off momentarily) to non-volatile memory and won't be lost even if he lets his batteries run all the way down without shutting his receiver off.
Keep in mind that this limitation only applies to the Meridian GPS BASIC model. Other versions of Meridian (GOLD and PLATINUM) have separate memory for software and user data which allows user data to be saved in non-volatile space in the background during normal usage.