Rule of thumb is don't buy batteries off ebay.
I was considering purchasing second hand ones, and even considered getting a droid 2 battery second hand, so at least it might be genuine moto, but thought better of it and feel validated with my choice.
At the end of the day, the battery can potentially fry your entire phone the second you connect it. You can't seem to get them direct from moto, but I'd suggest contacting your service provider and see if they can order genuine parts.
I suggest getting a portable charger for those outings where you know you will need some more battery life. Get a car charger, and if possible, a spare charger for work. Than most of your bases are covered
and safer too