Using a car battery to power drill and more???

Will hooking up a 12v car battery to a 12v drill work ok or will I fry it I thought of making a adepter sow I could use a car battery and has any one bout recondition power tool from harbor fright and how do they hole up are they worth it thank Rod MI

I also bought a reconditioned Homelite chainsaw from them and I had to dink with the carburator to get it to run correctly, no big deal.

Bigdog did a good job of explaining what I would have said. Think about this.....the same 12V test light can be used to check a car battery or a lantern battery. If the difference in available amperage could overload the bulb in the test light, a different test light would be needed for each of these supply sources. If this were the case, things would really get interesting in something like a car, where loads(lights, AC, rear defroster, cigarette lighter, etc) may be switched on or of in any combination. And, the excess current available in the system varies with the charge of the battery, output of the generator/alternator, and the individual loads placed on the system. If devices were effected by the amount of excess available supply current, each device would require its own individual means of regulating its supply current. Hopefully this helps, rather than confusing the issue...Al English

Although Big Dog is very correct, a current limiting device should be put in the circuit to avoid melting the coils in the drill during a stall. It is very true the drill will only use the amount of current it needs, but during a stall, the battery pack will not deliver enough amperage to melt it down, a car battery will give it all the current it wants and may smoke it.

For an example here, take a home ac unit, say it only pulls 20 amps normally, but a locked compressor rating would be 90 amps. If you had 100 amp service, the ac would only use 20 amps until it stalls, then it's going to grab everything it can until it trips the breaker or a safety reset, in this case, the breaker is the current limiting device and usually would be set around 30 to 40 amps in order to give you the start amperage needed.

Also, since there is much more current available, the drill may not stall near as quick, which means the current will be much higher as the work load increases and can still be detrimental to the drill.

Some drills, have an overload button on them. If it does then it will work fine as that is your limiting device.

You are talking about overload protection, and I agree with your comments on that. However, the original question was about whether a source with a higher reserve amprerage capacity would damage the tool.

I do have some thoughts on the following statement you made:
Also, since there is much more current available, the drill may not stall near as quick, which means the current will be much higher as the work load increases and can still be detrimental to the drill.

When the drill is powered by its original small battery increased loading will cause voltage drop, which results in overheating. Using a larger battery will avoid this problem. As a result the motor will actually run cooler at a given load. Its the same situation that causes a motor to run hotter if a long undersized extension cord is supplying it. In my experience overloaded hand tools warn you by getting hot, smoking, and smelling, before they suffer permanent damage. But I can't argue against your idea of using a fuse or breaker...Al English