# 240v to 110v advice



## 90575 (May 1, 2005)

Hi all us again, after having enjoyed a break in Cornwall in our Fleetwood Tioga and having burnt out 2 invertors whilst watching TV, then having received silly quotes to convert our RV to 240v (£1000.00 plus) we thought maybe we could do this ourselves?
My idea is thus:
As I work in the building industry getting hold of 240v to 110v transformers is no problem, so our idea is that the mains hook up lead coming into the van splits into 2, one side going into the transformer thus giving us a 110v supply to power the fridge/microvave/lights etc, the other side goes by way of a fuse box to a couple of 240v sockets so that we can enjoy our TV and hairdriers etc (her not me!!!)
Can anyone see any potential problems with this? I assume that the battery charging would not be affected as the transformed 110v side would only be the same as being plugged into the onboard 110v Generator (my one worry is that the battery would be being constantly charged and consequently cooked,but as I said it's the same as using the gennie for prolonged periods so I assume the charger cuts out when the battery is full)
Any advice and tips would be gratefuly appreciated.
Thanks a lot


Ian & Kay


----------



## johnsandywhite (May 9, 2005)

:lol: Hi *Yorkscouple*. I have done this myself on several occasions when on a campsite. The only problem with using a Transformer is that the Microwave will run slower as will the Fridge. You won't really notice it. It's because the US electric runs at 60 cycles AC ours runs at 50 cycles AC. You could do a proper conversion by using a step-up/stepdown transformer to allow 110 to 240 and 240 to 110. :-


----------



## Scotjimland (May 23, 2005)

Hi Ian 

The high cost of conversion is due to the cost of the transformer. I concur with JSW about the 50hz / 60hz but that's normal for all conversions. 

Check the wattage of the transformer, you will need at least a 3kva or bigger. 
Go for it :wink: 

Jim


----------



## johnsandywhite (May 9, 2005)

8O A certain company quoted me £1500 for a conversion with 4 x 240 sockets. I can do it myself for around £200. :wink:


----------



## Scotjimland (May 23, 2005)

johnsandywhite said:


> 8O A certain company quoted me £1500 for a conversion with 4 x 240 sockets. I can do it myself for around £200. :wink:


Very true John, I should have said 'partly' due to the cost of the transformer.. £200 sounds about right

>>>Transformer Supplier<<<

Jim


----------



## johnsandywhite (May 9, 2005)

:wink: That's the one Jim. :wink:


----------



## 90575 (May 1, 2005)

*Thanks so far*

Thanks for the advice so far guys, at least my idea is not as daft as the wife first thought, I must admit that a step up/step down transformer confuses me, how does it work, does it do both and how does one wire it?, any advice please JSW as obviously you have done it before (or even better can we come and pitch next to you for a couple of days whilst you do ours), only kidding we realy appreciate your help
Thanks a lot


----------



## johnsandywhite (May 9, 2005)

:lol: Hi *Yorkscouple*. I could of course do it but I am afraid not for nothing. The step-up/Down transformer has a strip connector for the 2 different tappings. One pair for the 110 volt and the other pair for the 240. It's fairly straightforward to wire the incoming 240 volt shore power through the transformer to the 110 Internal supply and visa-versa the generator 110 volt supply through the Transformer to the 240 volt sockets you would fit wherever you wanted. :wink:


----------



## Scotjimland (May 23, 2005)

*Re: Thanks so far*



Yorkscouple said:


> I must admit that a step up/step down transformer confuses me, how does it work, does it do both and how does one wire it


All it means is that it can be used either way, step up from 110v to 240v or step down from 240v to 110v 
Wiring it is simple, the terminals will be marked 240v , 110v and centre tap which is neutral and common to both windings.

Input on the 240 and common terminal 
Output on the 110 and common terminal


----------



## 88966 (May 11, 2005)

Hi Guys,
Just a word of caution, I don't know how your generators are connected to the 'vans system but make sure you cannot motor your generator when you connect your 110v.
I have a generator in my Hymer and it was not pointed out to me that when 'hooked up' there is a switch to disconnect the generator - I wondered what the strange noise was when I plugged in the hook-up, fortunately I plugged in at the mains first and into the 'van last. I know this is controversial but it probably saved me a generator !


----------



## johnsandywhite (May 9, 2005)

8O That could be a problem with European Motorhomes. With US Rv's. Most either come with an automatic switch over unit or the Shore power has to be plugged into the Generator receptacle to provide power from the Generator. :wink:


----------



## 90575 (May 1, 2005)

*thanks*

Thanks for the info on generator motoring, my RV has a lead that plugs into the generator to provide power into the van, when on hook up I plan to unplug it from the gennie and plug it into the transformer,sounds easy doesn't it (I will let you know when I have done all the wiring..........)
Cheers guys

Ian & Kay


----------



## 88926 (May 10, 2005)

Just fitted an 8kva transformer to my Revolution cost including delivery £326 this transformer has 2x120v outlets to be able to run the 240v for wire american system,Everything seems to be working fine other than the same problems John mentioned also the timer on the washing /drier does a wobbly every now and then but the wife doesnt leave it running while we are away from the RV.The inverter/battery charger works ok keeping the batteries fully charged.We bought a 100 to 240v dvd recorder from Asda also lcd and dvd player for the rear and a 12v digi box off ebay for the satelite,i also purchased the correct lnb and the trac vision satelite dome system works perfectly.The only thing left is to get a 110v to 240v step up transformer to run the 28" tv up the front or run a couple of 240 sockets through the RV.The only advantage with the step up tranaformer for the tv would be that i could run it off the inverter (2000watt) or generator if we need to,i might add that we have all usa appliances on board from toaster to hair drier.I havent got the company details that made the transformer but it could be JMS (peterborough) if you want let me know i will post it later


----------



## eupho (Jun 3, 2005)

I have installed a similar 240/110v setup to the one under discussion.
This has worked well during an extended tour of europe and several shorter breaks in the uk.
I do however find that on some occasions I have to switch on the transformer 2 or 3 times, each time tripping the site contact breakers, before it will start. 
I understand from the transformer supplier, and others, that this is a normal feature of transformers and is caused by the high inrush current generated if transformer happens to be switched on at the peak of the cycle, and not due to my particular unit.
I have recently fitted a "reich" fuse control inside the coach which, on initial indications, appears to have drastically improved the situation.
By setting the control to the site amperage or slightly lower, if it is going to trip it trips the control unit before the site supply allowing re-setting from inside without a trip to the bollard, or site office if bollard is locked, being neccessary.
I would like to know whether this is indeed a common problem and if so whether there is a better solution to the one I am using.


----------



## johnsandywhite (May 9, 2005)

8O Hi *IanH & eupho*. I don't understand why you have fitted an 8kva transformer Ian. The maximum amps avaiable at most camp sites is 16. Unless of course you are a future hopeful that they will start to fit 30 and evern 50 amp services like in the US. Doubt it. IMO. *eupho* the reason it trips is because the campsite amps are too low. If you make sure everything appliniance and service is turned off in your rig before you couple and turn on the shore power connection. You should not have the problem of it tripping. I was on a campsite in Spain for 5 years and we had the same problem. The same even here in the UK. Worth trying anyway. :wink:


----------



## eupho (Jun 3, 2005)

:roll: Hi johnsandywhite,
Thanks for reply, I have tried the method you suggest but it is still in the lap of the gods whether it takes or not. It is however comforting to know that the problem, if that is what it is, is not confined to me.
Apparently the problem, according to the manufacturer, is caused by the start up inrush current which can be surprisingly high, to quote them:
"We have calculated theoretical in rush currents and they are as follows:
750va 49amps
1000va 76amps
1500va 140amps
2000va 185amps
3000va 337amps
Please note these are absolute instantaneous maximum currents which assume the switch on point is at the crest of the AC wave form. In more realistic terms, I suggest you assume quarter of the values given above"

There appear to be other factors which can exacerbate the situation, one being that site contact breakers, or home come to that if you are hooking up there for maintainance, should be type C, and not the normal domestic type B.
I also spent some time searching, unsuccessfully, for a Soft Start switch. 
As stated earlier, it looks as if the Reich Fuse Control will be as good as it gets, for me at least.


----------



## johnsandywhite (May 9, 2005)

:lol: Hi *eupho*. Although nowadays I am not a regular Site user. I find the best way is to couple everything in with the onsite switch off. Then click the trip switch on. Then if it trips you are there to switch it back on again. :wink:


----------



## eupho (Jun 3, 2005)

Hi johnsandywhite,
thanks, next time as long as the breakers are accessible, I will try your method although with my fuse control set I am not anticipating, fingers crossed, further inconvenience.


----------

