How to set up an inverter

I’ve just purchased an inverter for my car which converts dc to ac through the cigarette lighter. I would’ve thought that you just plug the cigarette lighter plug, into the cigarette lighter but it says in the manual ‘If the inverter is to be used in a vehicle ona temporary basis and will be powered by the cigarette lighter socket in the vehicle, the earth terminl should be connected via a short link to either the negative or positive dc input terminal of the inverter’. What does this mean?

Your inverter got Plus, Minus and Earth on the AC side.
Your car’s obviously DC and got Plus and Minus, no Earth, a car is a farady cage, no earth, standing on rubber wheels as well. So the cars minus = “cars earth” usually the minus of the car´s battery is connected to the cars body.

They say to connect the earth of your inverter to the minus of your car - i don´t see why you should connect it to the cars plus.
But if you´r unsure what you´r doing, let someone with knowledge do it. A kiss from a car battery got enough punch to make your gorepump stop or reset your short term memory :smiley:

What arexma said, only that AC has no plus neither minus.
Electronic equipment is grounded for safety, noise reducing and other reasons.
When there’s no connection to real ground (earth) as in car, one pole of power supply is used as a ground - typically minus. However that is in DC circuits. I’m not sure that happens if you ground AC circuit which is generated from DC. And depending on plugs configuration, wiring might be tricky. So you better consult someone with direct experience/knowledge.

That sucks. All the inverters I’ve ever had allowed you to just plug them in the cigarette lighter, then you can plug your stuff right in.

So the cars minus = “cars earth” usually the minus of the car´s battery is connected to the cars body.

Some cars have the positive wire connected to the frame, some have the negative connected to the frame.

My guess…

Your inverter came with a cord with a lighter plug on one end and bare wires on the other and your inverter has two screw-on terminals (red and black) to attach wire to.

Take the wire with the stripe (or some other indication of positive) and attach it to the red terminal and the other wire and attach to the black terminal.

If in doubt get yourself a 12v lamp (like the one from the interior light), find a good ground (like an unpainted bolt holding the door on), touch the lamp to the bolt and the wire to the lamp (on two different prongs) – whichever wire lights up the lamp is the positive wire…assuming you have a negative ground like pretty much every car manufactured in the last 60 years (my old '53 Dodge had a positive ground).

Also assuming that the inverter even came with a lighter plug, not all do.

Oh, and if you manage to burn down your car for following this advice then it sucks to be you.