I carry a laser-beacon (for surveying) with a big ni-cad pack in it on SV, GF, QR, EK, with no problems (though Arrival Customs always stop me ask WTH it is!)
Only problem was with "ARAMCO Air" who made a big fuss (other airlines stickers all over the case!) and I ended up walking out of the terminal and driving for 90 minutes instead of taking a 737 for 20 minutes (arrived just after the 737!) Hope that taking my already-issued boarding pass with me effed them up!
IMHO, it's just another piece of battery-powered equipment, not to be used under 10,000 feet, like the little flash-card still/movie camera that I always have with me in my lap-top bag. I could have ni-cads in that too, as well as my electric toothbrush and my razor. (many years ago, lap-tops had ni-cads, too!)
Maybe a call to the airline to explain that it's "just a slightly larger than usual ni-cad"
