Since I have such a large collection of Bosch Fat Pack batteries on hand, I thought it would be wise to pick up a Bosch charger. The model that I saw on eBay is called a Bosch BC-830 charger. They can be bought for $55 with shipping additional if you want to "Buy It Now." However, if you are willing to bid on one, you can get them for less. I paid $41 with shipping for this one.
They are surprisingly large. Easily looking like a little boombox. I will be opening one up so that I can attach some heavy duty cables and adding a couple of Anderson Powerpole connectors so that I can use it with my assembled pack.