Basic understanding

[Mel]

As I have often said, neither the OH or I are technical and would never undertake maintainance or repair on electrical systems. I ask this question out of general interest because I like to have an idea of how it all works:

When you attach a van to EHU, the mains electric charges the battery, right? But the three pin sockets run off the mains, right? So can you run a caravan on EHU without a leisure battery ( I have no intention of doing so).? If not, why not.

Speak slowly, for all I know the electric is pushed around by pixies
Thanks for your kind instruction
Mel

 

[JonnyG]

best not to as the leisure battery levels out things to 12 volts ish. without it in place the transformer could actually try pushing say 17 volts through your 12 volt system which includes some interior lights,the water pump electric toilet ect. which could damage them..

 

[RayS]

As said, probably best not, but should not be disastrous if you do.

The mains circuits in the caravan - for kettle, hair drier, chip pan etc ;are supplied from the EHU and so are the water heater, fridge, and space heater if you choose to do so. If you don't and - for example - run them on gas - the mains hook-up will never know and will go on just supplying your hair drier when you need it.

The on-board battery will - in a modern caravan - supply most if not all the lights at 12v. dc and perhaps one or two other things. the battery needs to be recharged (don't we all /) and so is automatically connected to the mains supply via a charger which takes it's power form the mains. This is like plugging your mobile phone into a charger pushed into a mains socket at home which charges up the battery in the phone.
The on-board battery will also power the motor mover if you have one and for this reasons need to be connected to mains electricity whenever possible ( but the box in the caravan will do this for you automatically).

So if you go to a site without a mains EHU, you will need to run your fridge, water heater and space heating on gas. Modern space heating uses fans and or pumps which run on 12 volt/battery regardless of whether the main power is mains or gas, so running space heating on gas for several (winter) days without EHU may reduce the on-board battery capacity to run your mover when it's time to leave.

I now realise I've been a bit sexist in my choice of appliances ( I only need a small towel to dry my hair) but I hope this may have given some idea of what the two electrical systems do.
Not very good at this, so please post specific questions if I've just added to the confusion.

 

[Mel]

Thank you Ray and Jonny, I get it now. I thought if 240v was running it, then it was running all of it. Clearly this isn't the case and 12v is still doing its bit here and there. No pixies involved anywhere
Thanks again.
Mel

 

[WoodlandsCamper]

No pixies involved anywhere

No, but there could be some elves from the elf & safety regime if you do the wrong thing with the 240 volts.

 

[Gafferbill]

So can you run a caravan on EHU without a leisure battery ( I have no intention of doing so).? If not, why not.

Speak slowly, for all I know the electric is pushed around by pixies
Mel

........the only people who can answer your question accurately are the makers of the specific caravan you are referring to.
Technically a 12 volt battery is not needed when on EHU but in practice it is only possible to operate without a battery if the caravan has the correct specification power supply / battery charger fitted.
..........as has already been said movers rely on a charged battery being present.

 

[Dustydog]

Unless things have changed in the last seven years caravan manufacturers do not supply 12 volt batteries as standard equipment. Strange that considering the amount of 12 volt items on borad. Would you buy a new car without a battery

 

[WoodlandsCamper]

Would you buy a new car without a battery

You are comparing apples with pears. A car will not start without a battery, but a caravan will when attached to the car or being pushed. However a van won't move using a motor mover if there is no battery. Cars have had batteries for over a hundred years but I don't think caravans have.

 

[saint-spoon]

I must confess to finding it a bit weird that in order to get out and about caravanning there was a lot of extra expense to be factored in, including a leisure battery. As for running the caravan without the battery yes you can but I personally wouldn’t for the reasons already mentioned. Think of it as being the primary power source powering the lights, water pumps and so on. The EHU is a bonus. In my youth the caravan my parents took us out and about in didn’t have EHU. 12v and gas was all there was. As my Dad said when he came to look at our portable lodging, “things have moved on a lot since the old days” which is very much the case. I think of the battery as being the main source of power and the EHU as being there to save gas usage.

 

[ProfJohnL]

Hello Mel,

We live in world where it simply isn't possible to always understand all the technicalities of what we use, we sometimes only want the necessary instructions on how to use them. We rely on the hope the designers and manufacturers have done their jobs properly so the equipment will do its job every time.

In terms of the need for a 12V battery in a caravan, it depends on the type of battery charging circuit fitted to the caravan. There have been several manufactures of chargers over the years and of course different models, so whether a battery is needed does depend on the type of charger or power supply fitted.

In general caravans manufactured up to 1985, a battery is essential to moderate and smooth the output of the charger. The period between 85 to 90 things began to change so, it will depend on the type of power system fitted, but since 1990 the units fitted should be power supplies, and a some of the caravans lower powered 12V equipment will run without a battery connected.

Whilst in later caravans a battery is not essential for the basic equipment, it is advisable and essential for things like motor movers.

 

[Dustydog]

The following is from a 2010 article in Caravan Talk. Interesting to see the different advice.

From Swift 2010 Handbook
The 12v system will operate from the battery charger, with no batteries in circuit. When the battery charger is switched on, power will be available to the control panel, and to the appliances and lighting in the caravan.
From Bailey 2010 Handbook
The 12 volt system is designed to work with a leisure battery in circuit and should not be turned on without one connected.
You need to check your handbook or put a good battery in circuit

 

[saint-spoon]

I think that this aptly sums up the problem. different ships different cap tallies and so on.

 

[chrisn7]

Unless things have changed in the last seven years caravan manufacturers do not supply 12 volt batteries as standard equipment. Strange that considering the amount of 12 volt items on borad. Would you buy a new car without a battery

This kind of thing is always irritating. Its the same with fresh and waste water containers. It would be far better if they were supplied and with a dedicated storage place too to optimise use of space. And a built in reel for the EHU and so on...Its quite surprising that van manufactures haven't caught on to providing approved branded accessories and aftermarket kit in the way car manufactures do. There are some options at the time of purchase and that's it...

 

[Hutch]

In the summer, we awoke to lots off beeping from the fridge, we still had 220 volt supply in the van, after checking out the electrical supply unit, found the DC, power unit had blown up, after a 140 mile found trip from Ludlow to Gloucester, to get a new unit, fitted it and all was well.
So on the Coachman 560, the power unit/ battery charger has a dc 13.0 volt 20 amp power supply, (which will run all 12 volt DC items), and a 14.3 volt dual charging system for the battery.
To sum it up you can run the Coachman without a battery, on EHU, but once both DC sides of the power unit blow up you have about 2 to three days before you have to cook everything in the fridge, as it needs a 12 volt supply to give the 220 volt side to work.
Chrisn7, I wonder how long before the manufacturers will introduce that idea about a built in reel, might look at that myself, but tend to use it as balance ballast.
Hutch

 

[crazyguider]

Hi Mel. We got rid of our leisure battery as we never go off grid. Sir Fixalot replaced it with a power supply that gives us 12 volts. No idea how it works, but he did send an email to PC about it. Sadly it was never acknowledged, which is a shame as it gained us extra weight allowance, and we don't have to charge the battery. On the downside we do have to stay on grid, but thats fine for us.

 

[intransient1]

Ok time to throw a spanner in the works,
A few years ago they showed new vans at the NEC Show that were all electric, but I can't remember if they needed a leisure battery.

 

[ProfJohnL]

Hello Intransient,

Yes I also recall an all electric caravan, but I too can't remember who made it or exactly when it was suggested, but my guess is it was before the caravan mover became available. I think that was a turning point because obviously the mover needs an independent mobile source of power, and the battery is ideal in that respect.

However prior to the caravan mover, it was entirely possible to design and build an all mains electric caravan. The major limitation is the 230V 16A supply limit, which means you have to manage you power usage to keep it within the 16A limit. There was work done to produce an intelligent load sharing system that would automatically reduce the current to the central heating when another high current short term device was switched on (e.g Kettle, or cooker).

In reality it would prove to be quite difficult because whist the caravan EHU equipment is rated for 16A, as we know not all sites actually offer 16A, 10A is not uncommon, and certainly in some continental sites its as little as 3A before the bollard MCB trips.

 

[Dustydog]

http://www.caravantimes.co.uk/news/makes/bailey/orion/bailey-caravans-goes-electric-with-launch-of-orion-evo-4-$21381013.htm
It was Bailey

 

[ProfJohnL]

Thank you Dusty,

However the model I remember was back in the 1980's, and it was only a prototype.

 

[WoodlandsCamper]

http://www.caravantimes.co.uk/news/makes/bailey/orion/bailey-caravans-goes-electric-with-launch-of-orion-evo-4-$21381013.htm
It was Bailey

Is it still in their lineup?

 

[Dustydog]

http://www.caravantimes.co.uk/news/makes/bailey/orion/bailey-caravans-goes-electric-with-launch-of-orion-evo-4-$21381013.htm
It was Bailey

Is it still in their lineup?

Not as far as I know. Seems to have been an experiment.

 

[Hutch]

On ny Coachmaan, when i select the heating/ water heating its either 4 amp or 8 amp,with a gas as an extra option. On French 4 amp sites, I only run the fridge on electric everything else on gas.
In Europe what gas do people use, ?.
Hutch.

 

[ProfJohnL]

On ny Coachmaan, when i select the heating/ water heating its either 4 amp or 8 amp,with a gas as an extra option. On French 4 amp sites, I only run the fridge on electric everything else on gas.
In Europe what gas do people use, ?.
Hutch.

It depends on which countries you are visiting. Camping Gaz is widely available across Europe, but it tends to be be Butane based, so its not good in colder climates. If you are winer caravanning you should be using Propane.

 

[Hutch]

I Really meant to ask, do people use, eueopean supplied bottles or refillable , ie lpg, etc. , I take calor light, and a camping gaz for the Gas BBQ. I didnt want to get techy. Thanks Prof.

 

[ProfJohnL]

I Really meant to ask, do people use, eueopean supplied bottles or refillable , ie lpg, etc. , I take calor light, and a camping gaz for the Gas BBQ. I didnt want to get techy. Thanks Prof.

You asked what "gas do people use" I don't think I gave a 'techky' answer!.

If I had I would have told you why types of gas are used in different situations, things like "boiling points" and rates of expansion, and kW output per m3. :evil:

You will find there are a mirriad of answers depending on what each caravanners circumstances are. Some will use local supplies, other will take their own, some will use reliable bottles ( many refillable bottles have EU origins anyway.and of course there is Camping Gaz which is widely available and if you are traveling a lot between countries that might be easiest to be certain of.