Where to buy XP Deus batteries?

Has anyone found a supplier for XP Deus batters for the remote, standard coil and headphones? (They all take the same battery). I found people selling the batteries on eBay, but only from Europe and China, so I'm kind of incredulous that I haven't found a supplier in the USA. How has everyone managed to keep their machines running at full charge and battery life without replacing the batteries?

If you know of a reliable supplier, please let me know so I can do a little maintenance to my rig.