Help needed: Understanding my electrics! 1989 Hymer B544

[Watoh]

Hi folks,

I've been putting this subject off for a bit.. but i need to bite the bullet and figure out my electrics. I'm starting from a real position of ignorance, it's my 1st motorhome and to be honest I'm not sure how it is meant to work.

Present situation:
Main engine battery works as expected, charges well, holds charge and does not get run down by the habitation area.
Leisure battery charges off the running engine only, does not charge when hooked up to the mains.
When on mains hook up the entire habitation area runs off 240 volts. There is a RCD in a cupboard in the habitation area.

Under the drivers seat is a "battery charger" labeled: Elektromatic LA 110 Batterie-Ladegerat made by Schaudt.

See image below


Here is where something is amiss. There is a black cable from the engine compartment that goes to the front of this box (the blue & brown cables seen above).
There is another cable that comes from the back of the charger and plugs into the white socket you can see in the picture. From this socket, the white cable goes to the leisure battery compartment with a 3 prog english plug that is NOT plugged into anything, there is nothing to plug it into. It would seem something is missing!

The leisure battery has a single cable connected to either terminal.

Can anyone explain this mystery of motorhome electrics please! I'm quite confused! I suspect it has been 'modified'. :idea:

Thanks for any help, i hope I have been clear in the present setup.

Cheers.

 

[K9d]

This is exactly the same as my charger, there should be a lead to the mains plug, 2 pin in your case, and the blue and brown lead should go to the leisure battery. It sounds like your have been rerouted to the engine battery.

I would have a look at the engine battery to see if there are extra wires attached to it.

The other possibility is that a fuse has blown or the charger isn't working.

Having another read of your post it sounds like the white lead should get power form the 3 pin plug, can you plug that into an extension lead to see if you get any power.
Am I correct it goes Charger-2 pin plug/socket-3 pin plug ?

 

[GRWXJR]

If I read your text correctly.....

The plug next to the charger in the white box is a Euro 2 pin AC input to the charger.

This in turn is being fed by a UK 3 pin plug on the end of the white cable, which you say isnt plugged into anything.

It sounds like this charger cant work as its not plugged in!

You can plug it into one oc the van AC sockets which should in turn have juice off your EHU to get it power, or run an extension lead out and plug the plug intk that.

Sounds like it might be just that simple if you are lucky!

G.

 

[Watoh]

Having another read of your post it sounds like the white lead should get power form the 3 pin plug, can you plug that into an extension lead to see if you get any power.
Am I correct it goes Charger-2 pin plug/socket-3 pin plug ?

WOW WOW WOW talking about a brain fart!

Plugging the english 3 pin plug (that is not connected to anything) into a socket in the habitation area could in theory complete the circuit and allow charging from the mains. Jesus wept, if this is all that was needed i feel very very silly!

Even though i'm in the middle of cooking and it is horrid outside I'm gonna have to check this now!

Will report back.

 

[Watoh]

It sounds like this charger cant work as its not plugged in!
.

Yes I'm feeling very silly!

I've only had it since June! i hate electrics!

 

[GRWXJR]

Dont worry! Feeling silly is free!

Much better than spending bucks on a diagnosis / fix!

 

[Watoh]

Dont worry! Feeling silly is free!

Much better than spending bucks on a diagnosis / fix!

Well I might need that too!

When plugged in the main RCD in the house is tripping!

I'll have to have another look tomorrow in the light... seems something is amiss.

Any ideas what to look at that would cause the RCD in the house to trip?

 

[K9d]

Yes I'm feeling very silly!

I've only had it since June! i hate electrics!

We all have moments like that

 

[K9d]

Well I might need that too!

When plugged in the main RCD in the house is tripping!

I'll have to have another look tomorrow in the light... seems something is amiss.

Any ideas what to look at that would cause the RCD in the house to trip?

So when you plug the 3 pin plug in it trips the RCD inside ?

I take it the RCD doesn't trip when the EHU is plugged in, only when the charger is plugged in.

I would check the 3 pin plug, assuming that's fine unplug the 2 pin plug and plug in the 3 pin plug, if the RCD doesn't trip that part of the circuit is OK. Then plug in the 2 pin plug if that trips the RCD then I'm guessing the charger is the issue.

In mine there is no 2 pin plug, someone in the past has wired it direct to a 3 pin plug and fitted a socket under the seat.

 

[Watoh]

Thanks k9d, i'll do some routing about tomorrow. Thanks for the help, its much appreciated.

 

[GRWXJR]

Well I might need that too!

When plugged in the main RCD in the house is tripping!

I'll have to have another look tomorrow in the light... seems something is amiss.

Any ideas what to look at that would cause the RCD in the house to trip?

The Euro is 2 pin, so theres no earth electrode. Its a stab in the dark, but RCDs look for any kind of earth leakage or potential difference to earth so I wonder if its just that the charger isnt earthed? Might be worth taking an earth lead from the body of the charger unit and bolting if to a good chassis earth and see if that does the trick, as well as making sure all the connections in the plugs are correct and tight (with it unplugged of course ).

 

[Canalsman]

I would urge extreme caution when dealing with 230v connections.

The house RCD is tripping - this suggests there's a fundamental fault.

Consider consulting an electrician before you injure yourself and/or damage the vehicle!

 

[GRWXJR]

I would urge extreme caution when dealing with 230v connections.

The house RCD is tripping - this suggests there's a fundamental fault.

Consider consulting an electrician before you injure yourself and/or damage the vehicle!

I do agree with the above.

I'd add though that as you had no rcd trip issues on ehu before you plugged in the charger, this strongly indicates that the problem is isolated to the charger circuit.

Ok dont mess with it if youre clueless, but this at least gives you an area to start the fault finding at.

Bear in mind the charger might have been left unplugged as the previous owners found the same problem and simply disconnected the charger instead of getting someon to fix it!

I realised after posting this, that you didnt say that the rcd tripped instantly when you plugged in the charger? If it took a short while to knock the trip off, the Odds that its a faulty charger unit get higher (as the charger warms up and the resistances change internally its exacerbating a fault enough to trip the rcd).

G.

 

[piman]

Hello Watoh,

the plug from the charger that goes to the white socket, is it two pin with a hole and does the socket have two holes and a pin? It is possible that the charger has some earth leakage and I don't believe it would have been installed without an earth to the case, as it is metal. But it is possible that the charger to plug and socket to the U.K. plug has been cross wired? no earth won't cause an rcd to trip but connecting a neutral to earth will. Without any test equipment, I would rewire the charger directly onto a U.K. plug, i.e. remove the original two pin plug cable from the charger and connect the three pin plug lead directly (Ensure the earth wire is connected directly to the metal case). Try again and if the rcd still trips then there is a charger fault.

Alec

 

[Deleted member 5816]

If the charger has NO earth connection there cannot be a leakage to earth so the RCD would not trip

( the case could be bolted to the chassis so could be earthed that way )

But if the cable to the charger is only 2 core it would indicate the unit is Double Insulated and requires no earth ( unless cable changed wrongly )

Alf

The Euro is 2 pin, so theres no earth electrode. Its a stab in the dark, but RCDs look for any kind of earth leakage or potential difference to earth so I wonder if its just that the charger isnt earthed? Might be worth taking an earth lead from the body of the charger unit and bolting if to a good chassis earth and see if that does the trick, as well as making sure all the connections in the plugs are correct and tight (with it unplugged of course ).

 

[Polar Bear]

When testing for faults it helps if you only test one thing at once. IE; charger or socket!
You could try testing the two pin socket with something like an electric tooth brush or other two pin adapter gadget to ensure that this is working.
If that works okay then the problem is in your charger.
If the electric tooth brush/gadget does not work/trips out consumer unit try cutting off the two pin plug and replace with an English plug and try it in an extension lead.
There is usually a reason that things in campers are not plugged in and that's because it's scrap!

 

[piman]

Hello Alf,

"If the charger has NO earth connection there cannot be a leakage to earth so the RCD would not trip "

That is true of original earth leakage breakers but modern breakers are residual current and measure the current in and the current back and if the difference is more than 30mA (domestic breakers) then it trips, an earth is not required. I also doubt if it is double insulated as it has a metal case.

Alec

 

[Deleted member 5816]

Hi Alec so with your therorie where dose the leakage go if the item does not work there is no leakage.
For a modern RCD to trip it must sense a imbalance that imbalance is why they are loosely referred to as Earth Leakage Trips

so no leakage = no imbalance = no trip.

Most RCD trip at about 27 / 28mA in total any leakage below this figure will not trip.

The first generation of Earth Leakage Trips were voltage operated and required a voltage of 40 volts to trip, subsequent generations of trips have all been current balanced types

As I said could be wired wrongly. ie working live to earth. remote diagnose I very difficult and fraught with trying to understand the OP.

Hello Alf,

"If the charger has NO earth connection there cannot be a leakage to earth so the RCD would not trip "

That is true of original earth leakage breakers but modern breakers are residual current and measure the current in and the current back and if the difference is more than 30mA (domestic breakers) then it trips, an earth is not required. I also doubt if it is double insulated as it has a metal case.

Alec

 

[piman]

Hello Alf,

I think we are slight cross purposes, I was only referring to an earth connection in the charger cable. I would anticipate a connection between the charger case and the van chassis and also a bond between the incoming mains to the chassis.

I haven't heard anyone call them earth leakage breakers for many years, by the way.

Alec

 

[Deleted member 5816]

this does not follow from your previous post I do not follow how an Earth connection is not required, as you stated in your previous post

That is true of original earth leakage breakers but modern breakers are residual current and measure the current in and the current back and if the difference is more than 30mA (domestic breakers) then it trips, an earth is not required. I also doubt if it is double insulated as it has a metal case.

Hello Alf,

I think we are slight cross purposes, I was only referring to an earth connection in the charger cable. I would anticipate a connection between the charger case and the van chassis and also a bond between the incoming mains to the chassis.

I haven't heard anyone call them earth leakage breakers for many years, by the way.

Alec