No power when on Car

[JustTowIt]

I have recently bought a 1998 Eccles diamond SE

On our first trip out we found that when on 240V only the interior side lights worked and wasn't getting 12v supply.

swapped the battery out for a fresh 110 amp battery and everything worked on VAN, but switch to CAR whilst on 240v no 12v supply.

this wouldn't be a problem but the charger switch was on and illuminated on top of the charger yet the battery was at 10.5 volts when we got home so it wasn't charging.

when I checked the fuses under the seat, next to the charger a couple of wires were free hanging so i popped them back in.

Anybody any idea why the 12v wouldn't be working off the electric hookup or have a wiring diagram for this model so I can then do some fault finding?

TIA

 

[Damian]

When you switch to the Car position that means the van is drawing power from the car battery for limited items, normally the water pump, toilet flush and maybe one or two 12v lights inside the van.
Unless you actually need to draw power for a short time from the car, leave the switch in either the van or central position.

 

[ProfJohnL]

There could be several different reasons why you have had this problem.

Obviously being a second hand caravan, there is no knowing what previous owners may have done and the wiring may have been tampered with leaving a fault. We obviously cannot give a definitive answer about that.

But there are also a couple of other things that might be the cause.

As Damian has pointed out, modern caravans are designed with a feature called a Habitation relay. This operates when the tow vehicle is producing power and it prevents certain caravan items from receiving 12V power. This serves two purposes, the first is to prevent the use of some appliances when being towed which could be hazardous. and secondly it would prevent you from flattening teh car battery if you left the caravan plugged in .

But another more recent situation has arrisen. Car manufacturers have been striving to make ICE cars more efficient , and some have started to use "smart " alternators. These limit the power the alternator produces, and it may not be enough to switch power to the caravan battery charging circuit.

There is also the possibility that you cars electrics have not be fitted with caravan battery charging circuit, or the auxillary circuit. Many manufacturers standard tow bar wiring looms do not have these circuits, you have to specifically request them.

And probably one of the most basic issues can be the actual wiring in the multi-way connector plug has corroded or not been properly installed.

 

[Ern]

I have recently bought a 1998 Eccles diamond SE

On our first trip out we found that ............

..............next to the charger a couple of wires were free hanging so i popped them back in.

If the wires were disconnected and you popped them back in, this may be a clue.
Have you tested the output of the charger with a multimeter?

 

[Beachball]

Hi welcome to the forum you should get a answer to your question that will help you

 

[JTQ]

If the wires were disconnected and you popped them back in, this may be a clue.
Have you tested the output of the charger with a multimeter?

Failing caravan PSU/chargers is far from unknown, as Ern observes a previous owner removing wires is particuarly telling, people don't do that for no reason.

There are several "good" refurbishers of our caravan's chargers, though a van of that age is likely to have a very basic unit that direct replacement of it could be the cheaper solution.

As said check with a multi meter your is working or not, if you don't measure about 13.4 V minimum, with it switched on whilst on hookup, then it is not.
Then if it proves "shot", identify the unit, then we can try to guide you on cost effective solutions if you need to go the DIY route.

 

[audiorob]

I think it could also be worth asking about connection between car and van - presumably the van has 12N and 12S plugs to serve the roadlights and auxiliary functions. If so are you using an adapter lead to a 13 pin on the car? Switching to 'car' then while in transit should be able to run the fridge and charge the battery. Are you able to check the appropriate feeds from the car socket(s) and adapter lead to ensure correct supply?