# Inverter questions - please humour me!



## Snunkie (Mar 21, 2011)

I know nothing about fitted inverters so a quite curious as to how they work. I've read through many inverter threads on here but haven't found the answers I'm after

I have the small plug in type inverters where I can put them in a 12v socket and put a 3 pin plug in them so I know how they work. But, if you have an inverter fitted, does this mean that I can plug things into my MH 240v sockets and they will run off the inverter when not On EHU? 
Or is the inverter still something that you have to plug an item directly into?


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## Mrplodd (Mar 4, 2008)

You have to plug your device into the inverter.

If you simply plug the inverter into the cig lighter socket you need to be VERY careful not to connect anything that draws too much current or you will blow the fuse.

A much better way I to connect the inverter directly to your leisure battery. Make sure you use substantial cable to reduce the voltage drop that will occur if you use thin wire.

They are a useful bit of kit but they do have their limitations (such as you cannot run a hairdryer etc unless you have a monstrous battery bank and a large output inverter.


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## Pat-H (Oct 30, 2009)

The answer to your question is no.
A fitted invertor won't provide the mains in the van via the normal mains sockets.
The invertor will have it's own "mains outlet" socket and from that you can drive a mains device.
As the earlier posted explained the battery power needed to convert 12V up to 240V and produce any sensible load is very high.

Take a mains powered hairdryer at say 500W (so not even a very powerful one) at 240V that's 2 amps (and a bit needed)
but from the 12V side feeding the invertor would will need 40 plus amps ! so from your 120AH battery you'd be lucky to get 2 hours use out of it.
And that assumes the invertors 100% efficient. Many are more like 80-90% efficient (hence they get hot)


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## Imbiber (May 11, 2007)

Snunkie said:


> But, if you have an inverter fitted, does this mean that I can plug things into my MH 240v sockets and they will run off the inverter when not On EHU?
> Or is the inverter still something that you have to plug an item directly into?


Hi Snunkie,

We had a 600w inverter wired into our system by Phil from Rhino installs, so the kids could have the Playstation running if off hook-up or whilst we were travelling.

We specified which 240v socket in the van we wanted to use and Phil wired the inverter to it. Works a treat but does eat into the battery bank capacity very rapidly if stationary for a day or two!!

When we're not using the 240v socket I turn the inverter off as it can slowly drain the leisure batteries by just being left on.

Hope this helps?


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## Addie (Aug 5, 2008)

You can hard wire an inverter so that your motorhome sockets become live when it is turned on which would then be overridden by you connecting to a mains supply. I believe forum member Techno100 wrote a post on how to do this but form memory you would need a good grasp of electronics in order to do this yourself.

If you are powering a laptop or charging a device which uses a transformer you are best opting for a 12v version of the charger. Changing 12v > 240v > 19v as in the case of a laptop of 5v in the case of a Kindle or Phone really isn't an efficient (or sensible) use of an inverter in my opinion.

The bigger the item you want to power, the faster the battery will be depleted. So a 2000W hairdryer will run at something like a 160 amps so if you consider a standard leisure battery is 110 amp hours you can see how quickly that would be depleted given that you would never want to run a leisure battery down that far.

I would only run a hairdryer from the cab battery while the engine was running as the alternator will return 140 amps (with an X250 Fiat with Air-Con) meaning the load on the battery is fairly low. We did this daily for a year with no issues.


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## rayrecrok (Nov 21, 2008)

Hi.

I have a Ring 2500 watt inverter running off two 120 amp leisure batteries which is plumbed into the 240 volt plug circuit, this will run the fridge, telly and microwave for a time when not on EHU, this is useful when travelling as the fridge can run on 240 volts and I can have the slow cooker on cooking something as we travel as the batteries are topped up by the alternator and the 120 watt solar panel on the roof

Oh and the grand kids can have the telly on to watch DVD's as we go along, a function which pleases them :wink: ..

So the short answer is yes if done properly.

ray.


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## SilverF1 (Feb 27, 2009)

My wife uses a hairdryer via our inverter, 240v output.

The inverter is 1800 watts, modified sine-wave type, connected directly to the two 85 amp leisure batteries, two 80 watt solar panels to charge when off hookup. The inverter 240v output is permanently wired to a dedicated double socket.

I've also swapped out most of the ordinary incandescent bulbs for Led versions. This reduces power consumption of the lights to about an eighth.


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## peribro (Sep 6, 2009)

There is a very useful article here by Clive Mott about how to set up automatic inverter switching so that all your sockets can be run through the inverter when not on EHU.

In our case I wired it independently with two new sockets that are connected to the inverter. The inverter can be switched on and off by remote control so that is all we need.


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## DABurleigh (May 9, 2005)

" I've read through many inverter threads on here but haven't found the answers I'm after "

Did this one fail, too? :-(

http://www.motorhomefacts.com/ftoptitle-65101-inverters.html

Dave


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## aldra (Jul 2, 2009)

our inverter has two dedicated plugs

near to the kitchen to run a Remoska or slowcooker when travelling , 

or charge the hoover and electric bikes again during travel--or when the solar panel is putting in maximum charge

never had a problem

but then again we are not interested in TV, hairdryers etc

Aldra


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## The-Cookies (Nov 28, 2010)

we have ours like this---

we have 2 sockets 

1 from mains 
1from inverter

all our sockets in van terminate in a plug which we either plug into inverter socket or mains socket.


so when off mains and using inverter all our sockets in van are live

recommended to us by another member on here

john


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## Pudsey_Bear (Sep 25, 2008)

We had 4 x 2 gang sockets in the Laika, all on EHU, but I rewired them so the 2 on the dinette/bed side were on the inverter, and the other 2 on the kitchen side were on EHU, We had 2 inverters a 600w which did the sockets and a 300w one in a cupboard which ran the TV and was, mainly a spare.

Mount the inverter as close as possible to the LBs and take advice on cable sizes and fuses.

Kev


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## aldra (Jul 2, 2009)

we could not wire into the main sockets as our generator is wired there

a bit disappointing as we would have liked to keep the bike batteries in the garage

may in the future look into another inverter just for bikes and hoover in the garage

Aldra


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## Sprinta (Sep 15, 2010)

I have wired in a 2000w Ring unit along with 2 x 86ah batteries which we will use all the time when away from hook up. It's so useful especially on day trips to use the microwave or toaster during the winter. Even the 800w microwave used for 10-15 minutes barely saps the batteries so I can watch football while the chef does her stuff :wink:


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## mr2 (Feb 26, 2009)

Pat-H said:


> The answer to your question is no.
> A fitted invertor won't provide the mains in the van via the normal mains sockets.
> The invertor will have it's own "mains outlet" socket and from that you can drive a mains device.
> As the earlier posted explained the battery power needed to convert 12V up to 240V and produce any sensible load is very high.
> ...


A fitted invertor CAN provide mains in the van via the normal mains sockets. I have an 1800w invertor connected directly to the leisure batteries & the mains output socket is connected to the mains circuit. When switched on, off hook up, the invertor provides power to all sockets and has operated successfully for 4 years. Comments regarding battery power needed for mains devices still apply.


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## CliveMott (Mar 10, 2008)

All options are possible.
You need to find out how yours is connected first.
Pure Sine Wave is without doubt best but they cost more. But they will run anything within their power capability.
You need very good / big batteries for all but the smallest inverter used infrequently.

Use gas for heating and electricity for technology and LED lights.

May the force be with you.

C.


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## Snunkie (Mar 21, 2011)

Thank you for all the replies

I'm not remotely interested in hairdryers either. My main problem is charging up my iPad 3 when not on EHU. We have the small type 12v sockets in the argos burstner hab area which require a hella adapter. The iPad 3 requires a more powerful charger (2100 -v- 1000 for the iPhone) and somewhere power is getting lost between the hella type socket. It charges fine in the cab from the standard 12v sockets whilst we're traveling but currently cannot charge successfully from the Han 12v sockets. I need it for work on the go.
The plug in inverter draws too much power and gets hot. I believe the sockets are only rated at 8amps compared to 10amps I think on standard 12v sockets. I guess the cabling to the sockets could also be inadequate to have them replaced with standard 12v sockets?


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## rjc1039 (Mar 5, 2015)

*Inverter Issues 2500watt*

Hi I have a 2500watt inverter fitted to my motorhome connected directly to my 2x 110amp batteries.
Once switched on will power all the 240 volt sockets, which has in the past operated the microwave, telly etc no problem.
Last week I switch on the inverter with no load connected, and the overload light came on and lots of smoke appeared.
I quickly disconnected it from the batteries in case of fire.
I recently had the garge inspecting the vans electrics for a fault.
If someone was to connect the mains hook up electric with the inverter switched on, would this damage the inverter?
As I cant see how its overloaded and now dead 
Any ideas please


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## rjc1039 (Mar 5, 2015)

Hi I have a 2500watt inverter fitted to my motorhome connected directly to my 2x 110amp batteries.
Once switched on will power all the 240 volt sockets, which has in the past operated the microwave, telly etc no problem.
Last week I switch on the inverter with no load connected, and the overload light came on and lots of smoke appeared.
I quickly disconnected it from the batteries in case of fire.
I recently had the garge inspecting the vans electrics for a fault.
If someone was to connect the mains hook up electric with the inverter switched on, would this damage the inverter?
As I cant see how its overloaded and now dead 
Any ideas please


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## jiwawa (Jun 22, 2007)

I find inverters confusing.

On the one hand people say you have to be incredibly careful so that you don't fry the batteries; but there are others above who mix an 1800w inverter with 2x80w batteries and 2x80w solar panels.

We have 2x125w batteries and a 130w solar panel. We need 5-600w inverter to charge our bike batteries but actually it might be nice to have the capability to use a hairdryer once in a while, or use a slow-cooker. We use EHU very seldom.

I'm inclined to go for pure sinewave as I've had poor experience with a modified sine wave (300w) with the laptop.

And I'd definitely want one that could be turned off and not draw power permanently - this one at Maplin looked quite good till I noticed it can't be turned off http://www.maplin.co.uk/p/maplin-12v-pure-sinewave-600w-inverter-a27jg

Can anyone recommend a unit?

Thanks.


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## DABurleigh (May 9, 2005)

It can be turned off. That's what the red rocker switch is for. 

Check your hairdrier has a 600W or less setting.

Dave


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## TheNomad (Aug 12, 2013)

We go away for months at a time and are almost never on EHU.
I bought a secondhand 1800 modified sine wave Sterling inverter from ebay last year. 100 quid.
It has a remote on/off switch, powered by a small diameter cable.
I've hard-wired it right next to our 2 X 125 Ah leisure batteries. We also have 3 solar panels on the roof, totalling 230 watts.
The inverter is wired up to a single mains socket, which we then plug any mains item into when needed. It runs the Bosses 1200 watt hairdryer for ten minutes every couple of days just fine. Awesome bit of kit.
We do also use a small plug in to ciggie-lighter 200 watt inverter for small-draw stuff like charging camera batteries. electric shaver, hair clippers, etc.


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## jiwawa (Jun 22, 2007)

Dave, 1 of the reviews included "Cons: Uses 6 watts when idle, not great for a 24/7 setup as it would throw away over 1 Kwh of battery per week" so I assumed it wasn't possible to turn off.

Must go to Specsavers - I thought the rocker switch was an on/off light!

I guess 600 isn't much of a hairdryer. I _think_ mine is 1200, but Specsavers calls again!

I know it's better not to have a lot of spare capacity in an inverter as it's not terribly efficient, but I'm thinking it might still be best to have 1200 (or more?) just for the convenience of being able to use the hairdryer on occasion, even tho it wouldn't be the most efficient when recharging the bike batteries.

We normally full-time and wet hair in the winter isn't great :-(

Are Maplin inverters ok?


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## listerdiesel (Aug 3, 2012)

Waeco do a decent range of inverters, or you can buy one of the Chinese produced units.

We have a 550W Waeco in the trailer, a 125W one that we occasionally use, both modified sine wave, and a 1500W pure sine wave one to go in the Mercedes.

As far as small appliances like phones, tablets etc go, get a 12V adapter for them. More efficient and most small gadgets are USB charged anyway.

Peter


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## jiwawa (Jun 22, 2007)

Thanks Peter. We have a full panoply of 12v chargers for the small stuff and a 300w modified wave inverter which wasn't great with the computer.

It's the bike batteries have forced us to change,but it would be good to have hairdryer and slow cooker facility too.

Saw this on the net. Way too powerful for us but if it's a good unit, the discount is great (if the top line price is OK) http://www.sunshinesolar.co.uk/khxc/gbu0-prodshow/VP3000.html

Buy by 17 March.


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## peribro (Sep 6, 2009)

rjc1039 said:


> If someone was to connect the mains hook up electric with the inverter switched on, would this damage the inverter?
> As I cant see how its overloaded and now dead
> Any ideas please


I can't see how or why the inverter could be damaged by the mains hook up being connected and particularly if there was no load. I've used my inverter whilst connected to EHU and not blown it up. Odd though that you had had the electrics checked previously. Was a problem found or is there a bigger problem that somehow caused this? Alternatively could the inverter have been disconnected and reconnected wrongly? Lastly may of course just been coincidence and the inverter has reached the end of its life. Another possibility - could any moisture have got into it?


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## listerdiesel (Aug 3, 2012)

You can't have an active inverter on the same circuit as an active EHU.

The only exception I can think of is a grid-tie inverter which synchronises to the supply first and then puts power into the grid.

An unsynchronised inverter that is connected to EHU will be destroyed.

Peter


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## peribro (Sep 6, 2009)

listerdiesel said:


> You can't have an active inverter on the same circuit as an active EHU.


Agreed - and maybe I misread the poster's question. I was presuming that he meant that the leisure batteries were connected to EHU (for charging) and not that the same circuit was connected to the EHU and to the inverter. Having re-read his post it seems that that might be the case and certainly if both were active then I agree that something (the inverter) will have to give.


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## Pudsey_Bear (Sep 25, 2008)

JWW said:


> I find inverters confusing.
> 
> On the one hand people say you have to be incredibly careful so that you don't fry the batteries; but there are others above who mix an 1800w inverter with 2x80w batteries and 2x80w solar panels.
> 
> ...


Our slow cooker is fine it's only 120w, got it from Wilkos, we usually use it on auto while driving, but have often used it camped of EHU, the secret is to bring it up to temp before putting it in, then bring it back when you're ready, ours is a 600w inverter.


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## Pudsey_Bear (Sep 25, 2008)

JWW said:


> I find inverters confusing.
> 
> On the one hand people say you have to be incredibly careful so that you don't fry the batteries; but there are others above who mix an 1800w inverter with 2x80w batteries and 2x80w solar panels.
> 
> ...


That one has a switch (red) on it the same as mine, which also came from Maplins


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## DABurleigh (May 9, 2005)

JWW,

Maplins inverters are OK - good value for money but no, they won't have advanced circuitry to minimise the stand-by no-load current, so just switch off when not being used.

My principal concern is you full-timing in winter with two pretty standard sized batteries and wanting an inverter for a 1200w hairdryer. You really need a LOT of plate area to stop the inverter shutting down early from voltage drop, or use a 600W one with very disciplined use (more quick styling than drying from wet).

Hope you read the MHF members' guide on inverters I linked to earlier in the thread ;-)

Dave


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## listerdiesel (Aug 3, 2012)

Maplins sell the same as everyone else, their prices aren't bad but you can find better QUALITY units elsewhere, or cheaper on ebay.

I've bought from them, we one at Kettering and another at Bedford, same as Screwfix and B&Q.

Peter


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## jiwawa (Jun 22, 2007)

listerdiesel said:


> Waeco do a decent range of inverters, or you can buy one of the Chinese produced units....
> 
> Peter


I had a look at Waecos Peter. I think I'd have to win the lottery first!

I'm looking at 
A: http://www.ebay.co.uk/itm/1500W-300...368?pt=LH_DefaultDomain_3&hash=item2c72ad6970

and B: http://www.ebay.co.uk/itm/1500W-12V...671?pt=LH_DefaultDomain_3&hash=item3f47708b47

(sorry, I don't seem able to use the embedded link)

Although they're both rated as 1500W, B says Continuous power is 1000W (A's is 1500W). Also A is lighter than B.

Do you think A would be a reasonable buy?



DABurleigh said:


> JWW,
> 
> Maplins inverters are OK - good value for money but no, they won't have advanced circuitry to minimise the stand-by no-load current, so just switch off when not being used.
> 
> ...


Yes, I did read the article Dave. I'm afraid I have the kind of brain that just switches off when I read about electricity, no matter how hard I try!

Re the hairdryer - I would generally use for about 10mins on the lower setting (so less than 1200, but not sure what)


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## Pudsey_Bear (Sep 25, 2008)

Plug a hose into a blown air vent for drying hair.


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