Garmin nuvi 1350 DIY battery replacement help?

My nuvi won't start up completely. It begins to load, but turns off while "loading maps", then turns back on and repeats the sequence. Sounds like the charger/battery is not working properly. It has enough energy to attempt, but not complete its boot sequence. Tried USB charge and witnessed the same result. Think it might just be the battery. $99 to fix thru Garmin. Anyway to DIY and save money?