XBB24-A Battery Issues

I purchased Comcast's XBB24-A backup battery and connected it to my xFi modem/router.  There were no instructions with the battery other than a diagram on how to connect it.  Last weekend, my power went out as part of a planned safety shutoff by our utility company.  When the power switched off, the XBB24-A failed to keep the modem on.  I then unplugged the modem and plugged it back in, and pressed the button on the top.  A flashing orange (not white as usual) white appeared on the modem and there was limited Internet connectivity for approximately 1 minute, until the modem again lost power.  I repeated once more, with the same result, then I gave up.  I cannot find where Comcast has made any more information or instructions on this battery available.  Does anyone know why this battery would not work properly?  Thanks for your advice.