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John Henry

12 volt Electrical problem

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Hi There

I have a Hard top Conway pop up Trailer

It is kitted out with toilet, Hot & Cold running water to sink and vanity unit, 240 volt  electrics with lights and blown air heating.

All this works just fine

I have a leisure battery fitted which runs the 12 volt system.

The problem is when I switch to 12 volt it blows the main fuse when I switch anything on.

I have recently put in a high Amp battery from a diesel vehicle  …… could this be to powerful for the system to cope with ?

As I have not used the 12 volt system before as  the trailer came with no battery, and would really like the option of wild camping,  

Can anyone out there suggest a  DIY  fix

Could I run a high output inverter from the battery and by - pass the fuse board ?

regards for any advice 

John

 

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What size fuse is it blowing? and can you confirm its when anything is switched on it blows, eg lights.

 

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Hi there AJ

I believe it is a 20 amp thats blowing and it pops when I switch on the lights as that is normally the first thing that comes to hand and I have not tried anything else as it would appear to me to be a dead short and the electric circuitry on these pop ups are not  easily accessed, and at the time did not want to disturb to much in case I lost my 240 as well . And the wife without her TV is not a pretty sight

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Is it worth checking that the battery is 12v as you say it is off a diesel vehicle. 

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Hi There

it  was a new battery and came of my old Fiesta 35 TD ….1800 cc engine ….. and I believe they were 12 and not 24 volt

Could I fit a high power inverter to the battery and then plug a lead from the inverter into my hook up point thereby  internally running the 240, obviously not running everything at the same time just using appliances individually if we are pitched off grid, I have twin electrics so can charge the leisure battery either static or on the run .

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38 minutes ago, Grandpa Steve said:

Is it worth checking that the battery is 12v as you say it is off a diesel vehicle.  

The donor battery came off a Ford Fiesta, Ford Fiestas are 12 v .

 

Is there such a thing as a 24v truck battery ?

 

All the truck batteries  I and my sons know of  are 12v,

 

To obtain 24v for commercials 2 X 12 v batteries are connected in series !

Edited by Silversurf

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To continually blow the fuse there is a short circuit somewhere or something is drawing in excess of 20 amps. My guess would be a short so you would need to use a multimeter to track down the fault.

If not familiar with a multimeter to trace a fault of this type, get an competent electrician to do it. It could be something quite simple to fix. Or not.

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53 minutes ago, Silversurf said:

The donor battery came off a Ford Fiesta, Ford Fiestas are 12 v .

 

Very perceptive of you, however when I  replied we didn't know what the donor vehicle was.

 

Apologies for having the temerity to make a stupid suggestion about the battery voltage.

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Disconnect the battery, get your multimeter out and on the resistance scale measure any resistance as you switch each individual circuit on.   The device(s) in the circuit (e. g. lights for the lighting, water pump for the pump etc) need to be switched on.   For a 20A fuse to blow you are looking at resistance of less than  0. 6 Ohms (V=IR etc. ..)

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I wouldn't think its a battery problem and  if it didn't happen before you fitted the new battery, I'd start by looking at the battery connections, are they tight are they  coupled correctly and what else have you done?

I don't know if coupling the battery the wrong way round would blow a fuse, but I've seen it done despite the different sized terminals.

 

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As the OP states clearly that they've NEVER used the 12V system on the camper then the only way forward is to check out all the trailer's 12V domestic circuits carefully with meters. ..  (i. e. excluding road lights).

DO NOT connect battery to the trailer again before sorting that out.

 

There sounds to be some short circuits after the master on/off switch (assuming it has one).

 

Anyone know of an online  Conway handbook pdf source that may allow further, more accurate, advice to be given?

 

Most battery posts are a subtly different diameter between +ve and -ve to make reverse polarity connection less likely (but not impossible).

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14 hours ago, John Henry said:

Hi There

I have a Hard top Conway pop up Trailer

It is kitted out with toilet, Hot & Cold running water to sink and vanity unit, 240 volt  electrics with lights and blown air heating.

All this works just fine

I have a leisure battery fitted which runs the 12 volt system.

The problem is when I switch to 12 volt it blows the main fuse when I switch anything on.

I have recently put in a high Amp battery from a diesel vehicle  …… could this be to powerful for the system to cope with ?

As I have not used the 12 volt system before as  the trailer came with no battery, and would really like the option of wild camping,  

Can anyone out there suggest a  DIY  fix

Could I run a high output inverter from the battery and by - pass the fuse board ?

regards for any advice 

John

 

 

That suggests there must be a PSU on board to run a 12v pump. If that's true you must have used the 12v system before even if you didn't realise it. Is it just the lighting that blows the fuse? Post a pic of the switch and panel where you "switch to 12 volt".

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Many thanks to all who have replied to my post, lots of avenues to explore, at the moment the trailer is covered and tucked away for the winter,but rest assured as soon as spring is here I will be on the case and will keep you all informed

best regards

John

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