If I remember correctly above about 1500ma they start shifting to a angry blue. They will survive but the color of light looks terrible. The xp-e2 might be a better choice, mounted on copper for throw. http://www.mtnelectronics.com/opencart/index.php?route=product/product&product_id=107
What to expect in lumens with xp-e2. More Emitter Test Results (xpg2, xpe2, mtg2) Updated 11-12-12
Results for the xr-e. White LED lumen testing | Candle Power Flashlight Forum