12v invertor to power a 240v Applicance

A cigarette lighter plug is the last thing I would use to power an inverter. They are only good for a couple of amps current draw. The basic design of them is to power a heating element so a poor contact between the element and the positive supply is of some advantage. They are the only plug/socket connection where the connectors are not self cleaning.

The rule of thumb for inverters is to divide the power output by 10 to calculate the maximum 12 V current input requirement. Forum members often advise that a 300 W inverter is an ideal size. This will draw over 30 A on start up if the inverter starts on load, certainly too much for a cigarette lighter plug but you will see them being sold with cigarette lighter pugs attached.

This may not be suitable depending on the equipment being used. I have one of these plug in inverters and the output is ony 200V. This won't be enough for some things. I was told by an auto electrician that the best way to get good output from an inverter is to hard wire it in, as there is always some loss through a cigarette socket and plug.

Would like to take my Austar receiver with me, MyStarHD actually. That is all nothing else, so thinking just one PowerPoint adapter just for this running off the battery.

Ross M "If so, to be legal you will require a double pole 240v switch and a RCD safety switch to ensure electrical safety within a vehicle"

Well you don't have a bloody clue. You do not require a double pole switch on an inverter. RCD is useless on inverter and does not operate.

Don't give advice when you don't have a clue.

Make sure any inverter you buy is electrically isolated.
This Powertech inverter from Jaycar is 180W sine wave and electrically isolated and will power your Austar without issue. Jaycar Powertech MI5160 sine wave inverter

Toby should have added under no circumstances earth the inverter. Earthing an inverter in portable environment (vehicle, caravan, camper etc) is not recommended.

P2D2
Well you missed the point.
Read what was said.
IF fitting to a caravan it is legally reqiured to have RCD and double pole switching.
You may not need both with an inverter.
Also an RCD WILL detect current difference in the active and neutral lines if some milliamps are fed off by order of its higher voltage potential and the RCD WILL drop out saving you.

Because we didn't know what Timmo situation is we can only supply the norm.

From what you are saying it seems to indicate the 240v from the inverter is harmless and when it is touching a human it is ok.
Try some humid conditions in Darwin and or dusty inverter and appliancesand you will see a RCD does operate on an inverter. Just a safety thing. I have felt moisture related shock from 80v welders in this situation so 240 can fire 3 times the millamps with that PD.
Also have had inverter related shocks from bus mounted inverters.
Sorry to disagree but have seen it work.

Aren't you interested in safety?

Ross M how big a hole can you dig for yourself. Keep going because you are doing well. You will reach China shortly. You are absolutely clueless when it comes to 240V power in any form. A dangerous dangerous electrically clueless man.
Ross M do you realise it is illegal in most states to give electrical advice unless you are licensed?

So P2D2, are you licensed to provide electrical advice?

If you don't connect to the grid then nothing has to be legal and no RCD is required when using a 240v inverter and you don't have to be qualified to do this..... scary Ha!

The Act and regulations only come into play I think when the device (caravan) is to be connected to and run from the main power grid.

All GPO's, RCD's and anything else connected to the mail power grid has to be approved and meet Australian standards...... but you can by CHEAP SHONKY and OVER RATED inverters from china that doesn't.



(DISCLAIMER FOR THE insane...... don't try this at home and always seek medical advice or read our Product Disclosure Statements (PDS), not available in all states and you may need to be over 18 yrs of age to obtain a copy or to enter)

The issue is an RCD will not function on a portable inverter. Cannot work.
Ross M seen you are so adamant an RCD will work, PLEASE EXPLAIN

Ross M "Also an RCD WILL detect current difference in the active and neutral lines"
Ross M how do you change the laws of physics and get an active and neutral on an inverter? Certainly a novel idea.

Ross you may like to explain why you think a double pole switch is required?

Ross M "From what you are saying it seems to indicate the 240v from the inverter is harmless and when it is touching a human it is ok"
Well it is completely safe and harmless to grab hold any one wire from an electrically isolated inverter. Stand there all day if you like holding the 240V live wire from the inverter.

Ross M "80v welders in this situation so 240 can fire 3 times the millamps"
How is it possible 80V cannot produce the same 'millamps' as 240V?

To All and P2D2
If you have been reading this exchange, people say things for advice.
Initiall Toby didn't say if this was caravan based or other.
In Victoria it is a requirement, by law, to have double pole switching on 240v in caravans.
In Victoria it is a requirement, by law, to have RCD units fitted to caravans for the safety of humans. So, if using an inverter in conjunction with a caravan/campervan/camper trailer it is advisable to do so.

Very often inverters are used in places less than ideal and they have fans which suck in air and dust. Air for cooling and dust just happens. After a build up of dust and moisture from the air, the isolation some claim to be SOOO safe is now compromised and the current can flow from a faulty appliance and back to the circuit board in the "isloated inverter" indepandant of its 240v lead connections and kill you.
The RCD wil help here. I have felt shocks from dirty inverters via a faulty appliance, apparently P2D2 hasn't.

There is no real active and neutral from an inverter but it used appliances and switches and leads which observe this protocol. Commonly used term for the common person.
Because you can have leads and appliances which aren't wired as per the protocol then without the double pole switch to make everything safe, the coroners have insisted the double poles in mobile situations become mandatory.

Its the current which kills you.
I mentioned the 80v open crcuit from a welder and this voltage can push a certain amount of milliamps through the human body's resistance, you feel it.
With 240v it WILL push 3 times the miliamp flow through the same human body. Enough current to light a little LED will easily kill a human at 240v pressure.

If you grab the 240 wire as P2D2 suggested you can, and yes you can if everything is perfect, but if the inverter is dirty inside and you are touching its case or the vehicle it is mounted in, then the leak voltage will kill you.
I suggest P2D2 use a dirty dusty inverter in humid Darwin and see if he is correct.

As P2D2 has said, it is inappropriate and dangerous to give electrical advice unless you are qualified to do so. P2D2 however has not responded to my challenge as to whether he is so qualified.

Olcoolone (above) says that nothing has to be legal if not connected to the electrical supply grid. HE IS TOTALLY WRONG. Legislation exists to regulate the installation and maintenance of ALL electrical works regardless of the source of supply. Generally, automotive 12 & 24 volt DC wiring is not restrained to licensed electricians but Low Voltage (includes 240v) wiring and equipment whether in fixed premises or mobile installations and whether mains supplied or derived from private generation or battery-powered inverters is subject to legislation and to Australian standards.

All mains electrical appliances sold in Australia must conform to the appropriate legislation and Australian Standards, whether Olcoolone considers them "shonky" or not. Mind you, it may be possible to obtain appliances from overseas via the internet which do not have Australian Standards approval.

I cannot imagine that Oldcoolone has appropriate electrical qualifications when he makes the expressions that he does.

And yes, I am electrically qualified.

Talk about a little knowledge..

P2D2 posted:
"The issue is an RCD will not function on a portable inverter. Cannot work.
Ross M seen you are so adamant an RCD will work, PLEASE EXPLAIN

Ross M "Also an RCD WILL detect current difference in the active and neutral lines"
Ross M how do you change the laws of physics and get an active and neutral on an inverter? Certainly a novel idea."

Are you serious?

Most 240V inverters use the output of a step up transformer fed by a lower voltage AC signal. The two sides of the transformer secondary are connected to the Active pin and the neutral pin. Earth is connected to earth.

A RDC is designed to trip when there is current flowing to earth and a difference in the supply lines.

Of course it works.

AND P2D2 posted:
"Ross M "80v welders in this situation so 240 can fire 3 times the millamps"
How is it possible 80V cannot produce the same 'millamps' as 240V?"


You would need go to school and learn ohms law to understand this.

Dear P2D2,

Double pole switching of plug-sockets (GPO's) is required by legislation via AS3000 where the supply to the plug-socket is derived other than from fixed wiring from an MEN supply. Typically installations such as caravans connected by flexible cable from another plug-socket such as a park bollard. The reason for this is that such mobile installations can employ flexible extension cables which have been wired incorrectly resulting in the Active and Neutral conductors being transposed and so causing the Active conductor to be not switched by a single-pole switch plug. Similarly, all lighting switches in such installations (caravans) must be double-pole.

If you were not aware of this requirement and the reason for it then you clearly DO NOT have appropriate electrical qualifications.

Boobook said "Most 240V inverters use the output of a step up transformer fed by a lower voltage AC signal. The two sides of the transformer secondary are connected to the Active pin and the neutral pin. Earth is connected to earth."

All the quality inverters have the primary isolated from secondary of these transformers. Its only the older cheaper models that had an auto transformer in them. The secondary winding is not connected to anything. For an RCD to work one side needs to be connected to earth to produce differential currents through the RCD.

Yes, perhaps that was my grammar. I didn't mean to imply it was an auto transformer. I did meant that the secondary was isolated but either side of the secondary connected to the mains output.

You folk don't have a clue about anything.
You DO NOT need a double pole switch on an inverter in a caravan. There are NO laws covering inverters in caravans - NONE.
The inverter SHOULD NOT be earthed under any circumstances.
Auto transformers have not been used in inverters for longer than I can remember.
RCD WILL NOT work with an electrically isolated inverter.
There is NO active or neutral on the type of inverters we are discussing here.
Now kiddies you can all go back to play in the sand pit.

Before we go back to the sandpit P2D2, it would help us to respect the veracity of your electrical advice if you were to advise us of the actual qualifications you have in the electrical industry.

And that's QUALIFICATIONS P2, not just claimed knowledge or incidental experience.

C'mon P2, put up or............!

G'day to Toby, Boobook,Allen B and Nomadic Navara.

Thanks for your input and it is obvious you people have electrical experience.
I think you will find P2D2 or R2D2 or whatever has a new email address and forum name and has therefore reappeared after being silenced from the forum earlier.
His style of comments is familiar to many.
Regards

Ross M

Alan you a knob, if you can't talk sensibly don't comment and stop knocking others down. educate them and they will follow!

QUOTE[ I cannot imagine that Oldcoolone has appropriate electrical qualifications when he makes the expressions that he does. ]

I'm not an electrical and I'm the first to admit it AND where did I say I was?..... a forum is a place to throw ideas around and find the facts for helpful knowledgeable like minded folks.

I don't really care what QUALIFICATIONS you may or may not have.

Do you do your own brakes and suspension on you cars and trailers...... what about small plumbing repairs like tap washers..... are you qualified to do that work?

Ross M ROFLOL ROFLOL trying to deflect your ignorance and foolishness. Now trying to change the subject to try and hit the ball into the other side of the court.
Ross you have shown up your rank stupidity and ignorance on basic electrical matters. Now you want to duck and weave to avoid apologising for posting completely incorrect rubbish.

Allan B I won't embarrass you by telling you my qualifications. Other issue it would take to long.

Ross M and friends, do not post replies to matters you don't have a bloody clue.

Kiddies, back to the sand pit with your dummies and make sure you get the nappy changed.

I think you answered your own question and this is the best advise I've seen so far. Problem with asking questions like this on here is you have no idea how much knowledge the person offering advise actually has or how qualified they are. Personally I would never connect an inverter via the ciggy socket as mentioned. We had an inverter in our cruiser when we travelled. We had it hard wired by and auto elec. We also had a switch connected that we could disconect power to the inverter when not in use. This way there was no 240v power just sitting there. Remember power out of an inverter will kill the same as a power point at home so as you said, best getting professional advice. Two reasons.
1, if there is a problem with it and it causes a fire, you should be covered by insurance. I don't think an insurance company will accept "the guys on EO said it would be ok".
2, We don't have all the info needed to make a proper response. Where is it being fitted, How will it be connected, what other electrical devises are you powering, wire size to connect ect.
If your just connecting an inverter, you could do it or an auto elec can do it as it is only 12v going in. It will suck a decent amount of power so the wires connecting to the battery need to be the right size and the shorter the better.
If it is some other device with 240v an elec might be needed. Best talk to someone who deals in this industry. Just my 2 cents worth.

Josh

Toby,

No apology needed. This topic too often arouses the passions and starts a brawl!

Moving right back to your original question, I see that your device is spec'd as "50 watts maximum". That's within the capability of any of the small inverters.
I'd suggest go for a pure sinewave one such as this 600W one, (this is actually much bigger than you need, but smaller ones such as this 180W one or this 150W one cost almost as much so aren't such good value.)

I'll probably start a new argument about the merits of sine wave inverters, but I would stick with pure sine wave whenever running sensitive equipment, especially radio or TV gear. It does cost more, but other inverters can generate too much interference and you won't know how bad it is until you've paid your money.

Question - What are you going to feed with the Austar unit and how will you power that?

Cheers

John

My TV already is 12v and plugs in the cigar lighter input next to the TV. All works fine. I would like to SOMETIMES take my Austar box with me and be able to watch SPORT when on 12v ONLY. There is no extra 12v input next to the TV, hence my questioning about a 12v invertor to run my Austar Box ONLY. Also I have been places where normal TV reception is crappy and having a Sat dish and Austar will alleviate this matter somewhat. (Please do not talk about Vast, not interested). The funny thing is this weekend I am going to make sure my Austar box actually fits where I want it to go, otherwise I am going to scrap this idea all together!

That is exactly what I posted previously was a Jaycar Powertech 180W sine wave inverter. It was obvious from your post you wanted it for what is termed portable use, and when you posted it was for your Austar box is why suggested the 180W sine wave.