Hello & Welcome to Just Answer,
Sorry I didn't see your question earlier.
To answer you question directly, you should be able to use a USB -like car charger (rated at 5Volts DC output) to CHARGE a rechargeable battery pack (or equivalent) and operate the device at the same time - in most cases.
This assumes that the USB car charger is of good quality and does not generate a lot of "noise" that may interfere with operation of the device.
In reality, this device is DESIGNED to run from BATTERIES - for many hours (up to about 15 hours), and having rechargeable batteries installed along with the USB car charger would provide a "backup" - in case the car charger gets loose or otherwise is disconnected during operation.
NOTE: May sure you have the "Battery Type" set properly, based on the type of batteries you have installed.
I have included a link to the electronic (PDF) version of the FULL manual for you below, in case you need it for how to set the battery type (or other settings that may be useful).
I hope this helps. Please let me know what you find or if you have any more questions.
If this has answered your question(s), please take a moment to rate MY service level (Excellent is my goal) so that I get credit for helping you with this question.You should see some "smiley faces" or "stars" to do that, but please let me know if you do NOT see them or can not use them.
Thanks, ***** *****--. .-(im)
I noticed that you didn't mention HOW you planned on using the device IN A CAR, so if you plan on using it for vehicle navigation, you may be interested in the "Automotive Navigation Kit", which includes a vehicle power adapter, and mount, and a dashboard disc. You can see the details of that kit at the following link (Garmin's page).
If you want to see ALL the "accessories" available for this unit (including the above), then click the following link, then click the "Accessories" tab for a list. Each item can be expanded by clicking on the plus (+) symbol.
I hope this helps. Please let me know if you have any more questions.
And when you are ready, please take a moment to rate MY service level (Excellent is my goal) so that I get credit for helping you today. You should see some "smiley faces" or "stars" to do that, but please let me know if you do NOT see them or can not use them.
Thanks, ***** *****--. .-
Did you visit the links I sent - to see the accessories for this device - including the auto navigation kit?
I see it has been a few days and I just wanted to follow up to see if you have any more questions concerning this issue or if the issue was resolved.
I look forward to any further questions or results that you may have.