I have a Magellan 9212 GPS unit and am trying to find a car charger for it for continual use in the car. I already have the original "Magellan" one but wanted a second charger. Note, this unit was bought manufacturer refurbished and I have no clue if it has the truly "original" charger. The model is 629Z-001Z-Z180. It works with the GPS unit and I have been able to use it continuously in the car. I then bought a simple 2.1A plug for the car which goes into the 12V socket and gives me a USB power port. Then I bought just a regular angled standard USB to Mini-B (the only power/data input available on the 9212). It charged the GPS unit, but unfortunately did not work correctly it seems. The GPS unit showed the "charging" condition on the power bar, but ran out of power within about an hour. At that point, it would turn on for a few seconds when I unplugged and reinserted the USB cable and then the screen would go black, as if out of power! This was strange since it was just a normal USB cable plugged into a 2.1A lighter socket to USB adapter. Ought to be enough power for the 2A, 5V rated GPS unit.
The same thing happened when plugged into the PC for updating. I was lucky to have enough battery power to update the core software, but it failed during a map update, producing a "black" map with no info. Charging it overnight and updating the map again the next day fixed the problem, but it seems there are various angry customers whining about bricked units, presumably acquired in this fashion. Adding to this is the fact that the unit is often not recognized by the PC when using even a remotely long (6 ft) USB cable. I found a 2 ft cable worked more reliably. I think I remember Magellan stating that the unit can be charged by a USB cable plugged into the PC as opposed to using the car charger, but that this would take about twice as long. Seems that using a non-Magellan charger/cable provides less than 2 amps and thus causes an ON unit to drain the battery faster than it can be charged.
This got me thinking: if the Magellan unit pulls 2 amps and the standard charger-USB unit I have provides 2.1 amps, then any bottleneck would exist in the USB cable. So I assumed the USB cable would simply fry, but this does not seem to be the case. It seems it provides 1 amp and the unit only pulls 1 amp, which is not enough. It appears to somehow know to pull 2 amps from the Magellan car charger.
Even more shocking is that when I looked at the functional Magellan charger described above, it was only rated for 1 amp, 5 volts output! So how is the Magellan unit getting 2 amps from a 1 amp charger, when it can't seem to get 2 amps from a 2 amp system? The only thing i can think of is it's pulling 1 amp on the + and GND rails and another amp using 2 of the other 3 wires, which on such a USB cable could potentially be the Data +, the Data -, and the extra identifier wire found on the mini-B plug.
Just some more details about other Magellan units. The prior units, like the RoadMate 1700, had a separate mini-B data port for data only. It got power through a more conventional 2-pole DC in plug found on laptops and other devices. THAT adapter was rated for 2 amps and the 1700 unit was very similar specs-wise, such as being 7 inches just like the 9212. This seems to confirm the idea that the new unit is using some kind of other wire to get enough power.