Joined: Dec 2011
Posts: 2,519
Likes: 18
From: Fort Worth, Texas
Bikes: 2000 Bianchi Veloce, '88 Schwinn Prologue, '90 Bianchi Volpe,'94 Yokota Grizzly Peak, Yokota Enterprise, '16 Diamondback Haanjo, '91 Bianchi Boardwalk, Ellsworth cruiser
Just called the support number at Cygolite. The rep says the batteries are indeed compatible, but slightly different. The lower powered Pace/Expilion models use a 2600 mAh battery and the 600/700 lumen models use a 2900 mAh battery.
So I would get a longer runtime from the higher end battery, but it would probably not be a huge difference. I'm figuring it could make 15-30 minutes extra runtime, depending on what intensity you run the light at. He didn't have any actual runtime figures for me.
He did also confirm that the Pace is simply the version that is branded for sale through Perfromance & Nashbar.