no, imagine jump starting a car, but instead you cross the leads.
Say bye to the jumper cable lol... maybe even a splash of acid lol, no I was trying to work out if it's just 2 12v shorts or 24vs of short and where the electrons were traveling since there's 2 grounds.
either way don't do it unless you like burnt fingers...
on another note, getting a lithium 3v watch battery too hot makes it go bang, but it had a nice fragrance when it did....
ooh lots of molten jumper leads, sparks, sore hands :)
generally not recommended!
but as others have said it's like simply connecting a very low resistance across a low impedance 24 volt source
so v high current until something gives up
alternatively first think of the setup as two 12 volt batteries in series ( = 24 volts)
the -ve of one is ground
the +ve of t'other is 24 volts
the middle ( +ve of 1st, -ve of second) is "just" a centre tap
now put your zero-ohm load (the other wire) from +24v and gnd
stand well back!