The nuvi and Garmin Drive series devices do not have user replaceable batteries, with a few exceptions. The exceptions include the nuvi 500 series, 800 series, 805 series, and the nuvi 295W.
A replacement battery for the nuvi 500 series can be purchased on the Garmin website here
The nuvi 800 & 805 series and the nuvi 295W use a replaceable Lithium-ion battery as well. Although the replacement battery for these devices is no longer available via the Garmin website, you may be able to purchase a replacement through a variety of dealers.
All other nuvi models do not have user replaceable batteries. These devices must be sent in to a Garmin approved repair facilities if a battery issue arises. Garmin International is the only approved repair facility in the United States and Canada. To request a repair for your device through Garmin, contact support.
If you are experiencing battery problems visit the following FAQ: How do I charge my automotive GPS device?