An average lead-acid battery for a diesel car would cost about 0.6 of a CENT per hour of it's life !!!
Or in the case of the factory fitted Bosch battery in my Mercedes, now in its ninth year of service, 0.04 cents per hour.
And with 110Ah capacity and 1100amp cold cranking, it would almost certainly fire up a soft start APU. Don't know about the weight but is certainly smaller than the Li-on unit installed on the 787! ;-)
And, anything that has the capacity, can make fireworks too, NiCad included.
Exactly.
At the end of the day it is a box of energy and the more energy in that box the more potential for harm.