Power inverters: How much power draw?

I bought a 100w power inverter to plug in the battery chargers from my digital camera without having to buy a dedicated car charger. My 12v cigarette outlet is on even when the car is off. Does the power inverter impose a significant power drain on the car's battery when it is charging a small camera battery (similar to a cell phone battery)? How about when nothing is plugged into it? It has an LED to indicate it is plugged in, so I know it must draw some current. I just want to know if I leave my inverter and charger plugged in overnight, or my cell phone, am I likely to drain the battery? ...

There are too many variables to say yes or no to this question. Providing your battery is in good shape and all connections in the vehicle are good, you can leave it plugged in all the time and turned on. If you want to have it charge things overnight, then you need to use a meter to measure the current draw it requires while charging. Add that measurement to the normal current draw of the whole vehicle and decide. The acceptible current draw limit is usually 50 ma for the whole vehicle. Why not just use your charges inside at night.sparky

I won't be leaving them plugged in inside the vehicle very often. But sometimes I want to (or might by mistake). I don't need to charge the camera's battery often, and I don't want to forget it at home, so it's often more convenient to charge it inside the car.

The draw from the car battery wont be much of a problem with only a 100 watt inverter. I have a 250 watt and see very difference in my voltmeters when I start my car. In your case with only a camera battery it shouldn't do any damage at all. As far as the led on it gose again it shouldn'd make a difference.

First off, the inverter doesn't draw much more than what is required. So, assuming that it is a relatively efficient inverter with a low idle current, then you don't have anything to worry about. I personally wouldn't leave it hooked up over night. It might be fine a few times, but doing it regularly is asking for a low battery one morning. They usually don't draw more than 1 amp of current when idling though. Plenty low for when you are just leaving it in the car while you go into the mall or something.What is normal anyway???