12v inverter connection, battery drain?

Yes, you will need an inverter.  You will have to find a European inverter as US models run at 110V AC @ 60Hz.  Some appliances and electronics can deal with the 50Hz - 60Hz deviation, but since the electronics use the frequency for timing in the circuit, they can be prone to malfunction.

8 watts is very small for a 110v circuit.  With a healthy battery you will be able to run it for 24hrs without recharging.  However, that time frame is all dependent on how good the battery is, it's condition, and the overall current drawn from it.  When you add an inverter there is extra current draw than what it needs to product 8watts.  This is tied to the efficiency of the inverter.  There is heat loss, extra status LED's, etc. etc.  So there is no way to determine, without a doubt, that your battery won't drain.

BTW.  If the working voltage is 75V-100V, then a 110V inverter may cause damage to the sensor.

hey thank  you very much for the help!

I have an amp running in the back of my car, can i hook up the inverter, its a 200 watt model, and hook that up to the connectors on the amp?

Buds,

I am a newb, so forgive this simple question.

The positive and negative wiring that runs into my amp, on the terminals, can i wire my power inverter onto these terminals as well, sort of piggy back on it? I just really dont want to run more wiring all the way from my battery again!

Any help on this would be excellent indeed! thanks in advance.