most certannly
it of course wouldnt hurt if you checked the actual voltage comming off of the adapter, and get the polarity correct, and of course the external fuse.
what an Easy item to transfer to your dc.
even if its a AC transformer, it is VERY likely to work, because it would have a dc converter internally.
if the transformer was highly regulated Exacting 12v, and your batteries are pumped up to 14.5 (well charged) then just the wire (like some small guage) would be sufficient resistance to drop the voltage a bit.