Power inverters

I read the thread posted the other day about power inverters, but my question is how do you know how many watts you need? I only need to charge my Nikon EN-EL4 battery for the D2X. I don't need (or want) any real excess power as I will not be running anything else, and will only seldom need to charge batteries. I see where Radio Shack and others have 75 watt-150 watt for only $30-40. I have no idea how many watts my battery charger uses (needs). How can I figure this out?

Look on the back of your charger. There should be a bunch of numbers there and one of them will be the power usage (Watts). My Nikon MH-18 charger uses 15W.
So any of those inverters will do. But will you some day want to run or recharge your laptop from an inverter?

The minimum should be fine for battery chargers. I have a 400 and a 150. Check the back of the package and they usually give you a list of devices that will and won't work.

Thanks guys. I did what you suggested, and my charger uses only 23 watts. I very seldom take a laptop with me and can't imagine needing to charge anything else (never needed to in the previous 54 years ). The minimum should do nicely for me.

Thanks again.

This may have been covered elsewhere However be sure to look at the inverters "continuous" power rating. Many will advertize high power output, but they are speaking about "Peak" output. What you need to run the devices we use is continuous output.

Thanks Ed.

Bill,

It is my understanding that you have to be careful about the type of inverter you purchase in terms of sine or non-sine inverters. Apparently the non-sine can damage more sensitive digital equipment such as laptops, cameras etc. You may wish to due a bit of research in this regard before making a decision.

Dave