I want to be able to charge my laptop, the charger said 30w so it should be ok, but the inverter says 150w max. does anyone know if the inverter draws wattage in addition to what is plugged into it?

No it won't...

I just found an inverter online that says it has a .2 amp no load draw.

i found a calculator not sure if i should put 110 volts or 12.

with 110 volts that is 22 watts

with 12 volts that is 2.4 watts

:confused:

Most likely 2.4 watts but if you use a relay to power it on you don't have to worry about it!..a laptop doesn't require much to charge...the little ones you plug into the cigarette jack should work just fine! That's how I would to it...a 12v power outlet with a plug in inverter...

A quick search on eBay for 12v power inverter shows several for <$10

It's mostly been covered, but you should be fine. I design power supplies and inverters and stuff as a hobby, so I have some idea how they work. Anyway, charging a laptop is one thing, but actually USING a laptop is a totally different thing, and it can draw up to 3.4 amps at 19.5V, which at around 85% efficiency would be 80 watts drawn from the bike. That will kill a batter quickly if the bike isn't running, as is around the limit of your spare alternator current while running.
Of course, it's unlikely you'll be surfing the web while actually riding, so if you leave the bike idling with the headlight unplugged, you shouldn't have any problems using the laptop.

Thanks guys. The idea is to mount a 12v power outlet in my trunk box, and use one of those plug in inverters to charge a net book while i'm riding. I would also like to charge my cell phone, but not at the same time. and i don't need the inverter for that.

I think you would be better off just getting a cigarette lighter adapter for the laptop and using that directly.

Inverters always have a power loss for the conversion. The 0.2A is just its loss with nothing plugged in. Little cheapie inverters tend to be very lossy so you might be dealing with a 20% conversion loss. Add to that the conversion of the power supply back to 19.5V for the laptop. So basically, that 30 watts is costing the Ninja battery about 50 watts or about 4 amps. Its just better to go from 12V straight to 19.5V.

In any event, you don't want to plug it in while the Ninja isn't running or you'll run the battery down fast. And you don't want to leave the Ninja running or you'll burn up your engine.

You might also want to look at small solar panels for charging/running the laptop. Some of them output 19.5 volts directly. Kind of pricey though.

7 Portable Solar Laptop Chargers Worth Considering (http://www.treehugger.com/files/2008/10/7-portable-solar-laptop-chargers-worth-considering.php)

A cheaper option is to get two of these (http://www.harborfreight.com/15-watt-solar-battery-charger-44768.html), connect them in series, run the output through a 19.5 volt voltage regulator and then into the laptop connector. I've seen them on sale for $10.

http://www.harborfreight.com/media/catalog/product/cache/1/image/370x/9df78eab33525d08d6e5fb8d27136e95/i/m/image_17123.jpg