Yeah - my fault for not putting in the AA, sorry! That's interesting about colder weather - good to know.
Suggestions as to good prices for charger and batteries?
This battery and charger combo will work just fine as will other battery and charger combos.
I like overnight slow chargers as there is no way you can damage the batteries by overcharging. Four batteries allow you to install two in the GPS unit and two in a small plastic container when you need them.