Silly question????

[wasnotwas]

Was just wondering if i buy an inverter does this mean if i plug it into a cigarette lighter it will allow me to use appliances such as a hoover or tv on 240v also what is the best inverter to buy and what sort of drain would this have on my boat batteries also is it possible to hard wire an inverter into your boats electrical system..

 

[mikefleetwood]

The answer to the first part of your question is yes. An inverter will allow you to run AC mains appliances from your 12V supply.

As for the second part, it depends. The inverter you buy needs to have a "VA" rating the same or higher than the total "Wattage" (VA = W for all practical purposes) that you are likely to connect to it. You mentioned "hoovers" - bear in mind that an electric motor will draw considerably more current on startup than it's VA/W rating would suggest, and you should rate very conservatively, or it won't work at all!

The current draw will depend on the load you have plugged in - Whatever current the appliance would take from the mains, it will take approximately 20x that from 12V. There will also be a standing, no-load, current, but with a modern inverter that shouldn't be much.

There are other complications, but that should be enough to get you started. After that, go to chandlers/caravan shop and ask questions.

By the way, hard-wired will be better than cigarette lighter, but more things to consider in the wiring. Simplest just plug into the lighter socket and have a 13A socket on th eother end - usually limited power rating, but you can't go far wrong!

 

[timbartlett]

As Mike says, Yes, an inverter will allow you to run AC appliances from a DC supply -- that is exactly what it is designed and built to do.
BUT
(also as Mike says) bear in mind that the power of an appliance is usually measured in watts. In very simple terms (i.e.the reality is more complicated than this) Watts = volts x amps.
So if you have an appliance that draws 1 amp from a 240v supply, it will draw 20 amps from a 12vDC supply. If you have something that draws 3A @240v, it will draw 60A @ 12v and so on.
A domestic vacuum cleaner might be 1600W, and would draw 7A from a 240v supply, by which time you would be up to 140A from 12v DC. That's the kind of current that welders use. It is way way way beyond the capacity of a cigarette lighter: it would need quite a big inverter with a hard-wired DC power supply and cables whose conductors are at least the thickness of a pencil.
I'm afraid the fact that you are having to ask this question suggests that installing such a thing is not (for you) a DIY job.
So if you want something to run a laptop or a small telly, yes, buy one from Maplins or Towsure, and plug it into your cigarette lighter. If you want one to run a domestic vacuum cleaner, discuss it with a specialist such as Sterling.
And remember that if you are going to be pulling 120A out of your batteries for more than a few minutes at a time, you are probably going to have to increase your battery capacity and possibly your charging facilities in order to cope with the demand.

 

[hlb]

A cig lighter might run a modern TV but not an old one. Use it for charging phones and stuff. The cig lighter runs my TV But then I put the little honda on the pontoon. Then heating, charging and warmth all night. We can just about manage, two nights without power. But the little honda gives us full power all the time.
It's hardly not worth not having one, you can hardly hear it. Ok it will jib at the hot water and heating toungs. But if power is used sencibly it's fine.

 

[Csail]

Maybe no help but the van has 3500w inverter which just wrecks batteries, yacht has 1800w Sterling inverter which is perfect (powers most things) and we also have a 150w for laptops,printer etc.