# Inverters - an idiiots guide?



## GMJ (Jun 24, 2014)

Hi

Please be gentle as I am a novice and am getting my first MH in a week or so's time.

Could someone explain the whole inverter thing to me in plain English?

I am reading about them but getting confused as to their use. They appear to me to be some kind of power storage source from which one can recharge ebike batteries or the like.

If so, can the inverter be recharged itself from

- the cigareete lighter in a MH if you were on the move?
- a generator?
- the EHU if on site (or even the EHU plugged into the MH and then from a socket in the MH)?

Thanks

Graham :?


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## GEMMY (Jun 19, 2006)

Inverters:

Converters of one power source to another

ie. 12v dc to 240v ac

Different sizes for differing applications

100w will power tv with power to spare

Large sizes need bigger battery banks

tony


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## hogan (Oct 31, 2006)

The inveter works from your 12volt battery it basically turns 12 to 240 mains. 
They can flatten a battery very fast depending on the size of the inverter.


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## Sprinta (Sep 15, 2010)

an inverter is a gizmo that is (usually) wired to a leisure battery and converts 12v into a form of 240v.

The inverter can be as simple as a 150w unit to drive a laptop for example, or as in my case a 2200w unit wired into my 2 x 110ah batteries allowing 'er indoors to nuke my tea in a microwave.

using simple maths it can be seen that to get 2200w/240v out of a 12v battery will involve extracting 2200/12 = 183amps - that involves some seriously large wiring and as close as possible to the batteries. Fortunately the microwave is only 800w (66amps) although it has a startup spike of 1100w for a few moments needing an inverter well in excess of the operating range of 800w.

It is therefore not actually charged in itself, but is a way of changing voltages. You would typically use it when away from EHU.


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## listerdiesel (Aug 3, 2012)

Much as has been said already, but there are TWO main type:

Pure Sine Wave

Modified Sine Wave

Both will power resistive loads like filament bulbs etc., but only the Pure Sine Wave will power inductive loads like motors etc without extra noise or other issues.

If you just want one for the occasional use on charging a phone or a laptop, then 150Watts of either flavour will do the job.

Remember that what you put in is slightly more than you get out, and even with no load on there is a power drain on your batteries, just not as much as with full load on.

One I can recommend is the WAECO 550W Modified Sine Wave unit, compact and well made and runs a variety of gadgets in our trailer if we need it.

http://www.ebay.co.uk/itm/131067842307

I have seen them cheaper.

Peter


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## Pudsey_Bear (Sep 25, 2008)

listerdiesel said:


> Much as has been said already, but there are TWO main type:
> 
> Pure Sine Wave
> 
> ...


Hmm, been meaning to post on this subject since I got back.

I have a 600w inverter, hard wired into the LB banks, and it seems to do whatever I've needed so far, slow cooker and the PVR, also the coffee grinder, the only other thing I've needed it for is to charge the lappy battery, and although it does it, I do it with the lappy firmly turned off as it makes the transformer click like a Geiger counter, which surprises me as I didn't think anything in there could click.

For the OP

guide 1

Guide 2, with more techy info

Guide 3, more basic

Peter I sent a couple of emails to your Diesel address, did you get them?


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## Freddiebooks (Aug 9, 2008)

Hi GMJ,

As far as i am aware you do not charge an inverter. I'll explain what i do with mine.

When on a site without hook up (so basically summer months) i plug in my inverter to the cigarette socket in the habitation area. This draws the power from the leisure battery into the inverter and turns it into your normal 3 pin plug power. I use this power to charge my digital radio, Dyson Handheld vac, Smart phone etc If i was on hook up then i have no need for the inverter as i'd use the built in 3 pin plugs that are part pf the motorhome. 

I replace the power that is taken from the leisure battery via solar panel. The inverter (300w) i bought was approx £25 and well reveiwed on Amazon. It has a built in fan. I plug in an adaptor so can charge two of the above at the same time. I do it during the day so as power is leaving the leisure battery it is more or less is being put back straight away via the 100w fold away solar panel i have. The other way to replace the power into the leisure battery is either via hook up or driving the vehicle. So clearly solar is the winner. 

Works for me and can save a small fortune not needing hook up. 

Regards


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## GMJ (Jun 24, 2014)

Thanks for this folks  

Freddiebooks - that is what I call plain English - I understood it :lol: 

So I may need an inverter if I want to use 'normal' 3pin plugged items that require 240v and I can plug it into the cigarette lighter if I am not on an EHU? Gotcha.

Questions...

- The MH has a standard domestic socket in it: does this get a 240v feed in which case is there already some kind of inverter in the MH? I dont think this was an addition...it looks standard. Does this get 230/240v via the EHU?


- The MH I am getting comes with a generator. Nothing super duper just a £120 jobbbie. What voltage would this throw out and in which case would I need the inverter in between it and any domestically plugged items?

- Lastly there is a chance we would get an ebike for Mrs GMJ. Presumably I would need the inverter for this if I was charging via the cigarette lighter if on the move? Alternatively if plugged into an EHU how would I do it then?

Sorry 

Graham


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## Freddiebooks (Aug 9, 2008)

The MH has a standard domestic socket in it: does this get a 240v feed in which case is there already some kind of inverter in the MH? I dont think this was an addition...it looks standard. Does this get 230/240v via the EHU?

Yes, that socket will become live once you have plugged your cable into the side of your m/h and into the camp site power point.

Remember thou, the size of inverter dictates what you can use. So my 300w does light duties well but i could not run an electric iron or similiar off it. If your needs are such then you'll be looking at a much bigger set up.

I know nothing about Gennies, other than they are noisey and cost money to run.


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## GMJ (Jun 24, 2014)

Gennies:...but come free with the MH ...so gifthorse/mouth etc :lol: 

Thanks for the info on the socket.

Is there a guide somewhere on size/type of inverter and what it could power? Like a list of 'typical' appliances that could be run off certain rated inverers?

So, to use your example, yours wont run an iron but an XYZ rated one would?

ta

Graham


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## cronkle (May 1, 2005)

This may be of help to you

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

I knew it was on this site somewhere! :?


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## Pudsey_Bear (Sep 25, 2008)

GMJ said:


> Is there a guide somewhere on size/type of inverter and what it could power? Like a list of 'typical' appliances that could be run off certain rated inverers?


I've already posted links to three. Read those as they'll answer all your questions.


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## peaky (Jul 15, 2009)

we have two inverters 150 watt charges cameras laptops electric tooth brush the 750 watt runs the toaster and charges the batteries on our electric pro rider bikes.


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## aldra (Jul 2, 2009)

We have 1000 W
Charges the bike batteries, laptop phone, kindles Hooveretc 

The solar provides enough power on sunny days to use it

Other than that we switch it on when travelling and the batteries are on continuous charge and power the slow cooker

The onboard generator GAS powers directly to the 240 V system and powers anything, aircon etc in an emergency when not on electric hookup

Aldra


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## GMJ (Jun 24, 2014)

Right...I think Iv got it  

The inverter converts the 12v from the leisure battery into a usable 240v supply. Depending on the size of the inverter normal 240v powered devices can be then used.

The leisure batteries can then be charged up by either solar; a generator;or by the engine. When on an EHU there is no real need for the inverter as the 240v socket in the MH does the business.

If looking to wild camp or camp without an EHU for a period of time then it may be sensible to get a second leisure battery and/or a solar panel.

So all I need to consider is what devices I would realistically need to get power to if I was wild camping/non EHU-ing for a period of time. Potentially mobile phone batteries; hairdrier for the wife etc. I would also need to revisit this when/if we get an eBike so that I have the correct size of inverter for the batteries for that and also, I guess I would seriously need to consider a second battery then and/or solar as I am also guessing they may pull a decent amount of juice.

Edited to add: The decision also to be made is over Pure Sine Wave or Modified Sine Wave. It seems apparant to me the PSW are better; can do all that MSW can; but are more expensive.

Right...if this is all correct Im off for a lie down :lol: 

Graham


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## 91502 (May 1, 2005)

GMJ said:


> Right...I think Iv got it
> 
> The inverter converts the 12v from the leisure battery into a usable 240v supply. Depending on the size of the inverter normal 240v powered devices can be then used.
> 
> ...


Graham

In my opinion you are far better spending your money on 12v equipment and changing to LED lighting to make the best use of the power you have.
We don't have solar and can go away for 3 or 4 weeks and never need hookup, we charge everything by 12v and try and do this where possible while moving.
We do have an inverter but no longer take it as we never use it.
Using an inverter for things such as a hair dryer will very quickly run down your batteries and its very easy to run them below 50% and they will possibly never recover, a very expensive mistake to make.
Also only the smallest of inverter is safe to power off a 12v socket, the larger ones need to be hardwired directly to your batteries with the correct fuses and substantial cables.

James


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## aldra (Jul 2, 2009)

I disagree

Our inverter is hard wired 8O 8O 

Well it is wired into the van :lol: 

It keeps everything charged up and we are often not on hookup

High powered start up things, ie hair dryers microwaves etc we don't use anyway

And for me a solar panel is an absolute must have

The generator is overkill :lol: 

I just like to be prepared

Possibly the most expensive add on, rarely used but on the odd time I've needed aircon when no electric ....priceless

Aldra


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