NECRO MOVED FROM OT: Any harm in putting a smaller battery in a car?

[who?]

A bad voltage regulator will kill the battery but you don't need to replace the alternator unless the voltage regulator is a built in.

 

[Ken g6]

How's that battery running so far? I guess 15 years would be a good way to know if there's any harm in doing it.

He hasn't been seen in three years. His battery must have died or something.

 

[Genx87]

Your car may explode into flames.

 

[Perknose]

My Thunderbird battery died so I put one from a Ford Probe in. The Probe battery is noticably smaller, but appears to work alright.

I believe the OP was talking about the physical size of the case, not the cold cranking amps rating. You can put an lesser rated battery in your vehicle, but it may not be up to the job of starting said vehicle in extremely cold weather.