A couple of inverter question

[paul_374300602]

I've just bought a 150watt inverter from maplins £14.99 in the sale. I only want to run a small telly or radio for a short while for the weather forcast etc so reckon the drain on a 110amp/hr battery shouldn't be too much of a problem for a few days away without hookup.Can I wire the inverter direct to the battery and then feed the 240v direct into the vans mains inlet via a 240v plug and blue caravan mains socket so I can use the plug sockets in the van? also the inverter is supplied with a cigar lighter plug which I will remove, and an earth terminal. when/if it is used in a car for a laptop etc where would this earth be connected to the car?

Hope you can help,

Cheers,

Paul

 

[rob_jax]

Hi Paul,

Running a 230 volt appliance via an inverter and 12 volt battery supply - the current drawn from the battery needs to be 230/12 or roughly 20 times higher - that means that 20 amps are needed to supply 1 amp at mains voltage. And this ignores losses in the conversion process.

A small TV will probably need 80 (or so) watts - that's a current of 1/3 amp - so the battery will need to supply around 4 amps (probably closer to 5 or 6 amps to drive the inverter as well) for the time the TV is on.

Inverters are (probably) not certified for exterior use - so you'd need a long adapter cable to feed into the EHU point. But I think there will be too much chance of an appliance being left connected and inadvertently killing the inverter...

Robert

 

[Gafferbill]

Hi Paul

I have installed a 150 watt inverter in my caravan to provide mains power for my Sky Tv freesat system, when not hooked up to the mains.cigar socket lead direct to the fused outlet wire from the battery .

I did it this way :-

Retain the cigar socket plug on the inverter.

Buy a cigar socket lead from Towsure or similar (see Towsure website product number A26 or SE5)

Wire this directly to the main 12 volt fused supply wires.

These are found inside the caravan near to where the 12 volt supply leaves the battery box.

Connect to the fused +ve wire so that the supply to the inverter is fused.

Maintain correct polarity as this is essential for the inverter.

Place the cigar socket in a place for easy access.

On my Swift the battery box is in the front offside corner and the socket is above laid flat on the window shelf.

The inverter also sits on this shelf as it needs to be kept uncovered for cooling reasons.

Only connect the inverter to the appliances you are running not to the caravan circuit.

I use a 1/2 mt. 4 plug flat extension lead plugged into the inverter to gain extra sockets.

I plug the Sky box and the TV into this, and the total load is 100 watts.

The inverter is 90% efficient as yours will be.

This set up does not drain the 12 volt battery any more than a 12 volt spotlight

With such a setup you can use your laptop in the caravan or your car, simply take the inverter and laptop and plug it into your car cigar socket for car use.

Hope this helps.

 

[Gafferbill]

Hi Paul

I have installed a 150 watt inverter in my caravan to provide mains power for my Sky Tv freesat system, when not hooked up to the mains.cigar socket lead direct to the fused outlet wire from the battery .

I did it this way :-

Retain the cigar socket plug on the inverter.

Buy a cigar socket lead from Towsure or similar (see Towsure website product number A26 or SE5)

Wire this directly to the main 12 volt fused supply wires.

These are found inside the caravan near to where the 12 volt supply leaves the battery box.

Connect to the fused +ve wire so that the supply to the inverter is fused.

Maintain correct polarity as this is essential for the inverter.

Place the cigar socket in a place for easy access.

On my Swift the battery box is in the front offside corner and the socket is above laid flat on the window shelf.

The inverter also sits on this shelf as it needs to be kept uncovered for cooling reasons.

Only connect the inverter to the appliances you are running not to the caravan circuit.

I use a 1/2 mt. 4 plug flat extension lead plugged into the inverter to gain extra sockets.

I plug the Sky box and the TV into this, and the total load is 100 watts.

The inverter is 90% efficient as yours will be.

This set up does not drain the 12 volt battery any more than a 12 volt spotlight

With such a setup you can use your laptop in the caravan or your car, simply take the inverter and laptop and plug it into your car cigar socket for car use.

Hope this helps.

Sorry for typing error in first few lines!

Just delete the following :-

"cigar socket lead direct to the fused outlet wire from the battery" .

 

[WatsonJohnG]

Hi GB

I see that you have used the heavy duty cable to supply the cigar socket

I have done a similar thing but reverted to the Clipsall 2 pin plug as this gives a much better contact than the cigar type which I find tend to heat up a lot

I am able to plug a double surface 13amp socket feed into either 230V mains or 230V via inverter thus powering the TV and Sky+ box

 

[Gafferbill]

Hi GB

I see that you have used the heavy duty cable to supply the cigar socket

I have done a similar thing but reverted to the Clipsall 2 pin plug as this gives a much better contact than the cigar type which I find tend to heat up a lot

I am able to plug a double surface 13amp socket feed into either 230V mains or 230V via inverter thus powering the TV and Sky+ box

Hi John G

Your system sounds fine to me!

I only run a 150 watt inverter so do not have a problem with the plug heating up at all.

I am a bit tight, so I wanted to keep the cigar plug on the inverter so that I have the ability run some essential low wattage electrics on my Gas central heating system at home when there is a power cut. For this I use Towsure's Crocodile clips to cigar socket lead, clipped directly to my car battery. We have an attached garage so it is relatively easy to do.

Can also power the Sky system and 40 watt bulb the same way in the same circumstances.

With a 150 watt inverter it is a choice between heat or TV though!

I do not want to go to a bigger inverter as battery discharge is to great.

 

[WatsonJohnG]

Hi again Gb

I have a very similar set up with the 300W inverter where I can have the boiler on or the Tv/Sky in the event of a power cut

I fitted a 12V cigar plug to my wife's last invalid buggy and it could then work the gas central heating etc

Don't know what the new owners thought about a cigar lighter fitted to a buggy---reasons for needing buggy in first place maybe!!

 

[paul_374300602]

Thanks folks. As always very helpfull and comprehensive replies.Now I know wich way to go.

Thanks again.

Paul