Can I replace my dead car battery with a new battery from a different car?

Only two things that matter are - the cranking amps of the newer battery should satisfy your starter's draw in amps in all weather. If it's too high then your starter will go for a toss. Starters are made to operate at a certain voltage. For example, if the battery provides 12volts, the voltage dips while starting due to insufficient amperage ( that's why you see the lights dim) . Say it's 7 *while* starting. So the starter practically operates at 7v , not 12 (due to insufficient amperage caused by it's own draw..) and so does every other electrical component *while* you crank it. If you kick in a higher amperage battery, the voltage does not drop to 7 but rather 10 or 11- which is not what the starter is built for. nothing will happen right away but in the long run, the starter's life is compromised. The other one being the battery should fit in the holder and the + and - terminals should reach and connect. That's it.  more