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Just stripped out a faulty transformer / charger from my old maurauder van due to it deciding to spontaneously combust on me, filling the caravan with black noxious smoke!

Just in case any one wants to know the old unit that decided to go into melt down was a Danbury Electronics transformer with the following info on it: DB433 / DH35  50/60Hz 12v 50vA (you might want to change it?!!)

Anyway, I,ve stripped it out and I've bought a new one from BC electricals; it can handle 10 amp intermittent and 7.5 amp continuous.

I'm happy enough connecting the red fused feed and black negative returns from my 12v wiring to those of the new power supply (pretty obvious). What I'm not sure of is:

 1) What to do with the two wires (positive and negative) that are labeled up in my caravan 12v wiring as"vehicle battery". It appears that the "vehicle battery" positive originates from what I think is the 12S towing socket, whilst the "vehicle battery" negative was wired into the negative return of the old power supply.

2) Where to wire in the positive and negative wires that attach to the leisure battery. Even though I don't intend to use a 12 volt battery often, I still wan't the facility to do so. The new power supply will charge a battery as well.

3) All the 12v positive feeds from the lights, cassette flush, water pump, Carver Cascade GE ignition feed etc go into one terminal connection on the plastic connecting block; this seems like poor practice to me, even as a layman as surely one of these wires will eventually work loose. It is the same with the negative feeds (five wires into one connection). Is it possible to do a tidier job of connecting multiple feeds?

Just as a bit of background (phew!!) at the minute the main feed from the power supply is split; one feed goes to what I think is the 12S towing socket (green wire), the other is used to power the 12v equipment in the caravan.

The neutral from the transformer is similarly split between 12v neutral return and 12S towing socket (white wire).

I think the reason you wire to the " vehicle battery " (positive and negative ie the 12s wiring ) is so when you are towing the voltage produced by the car goes via the battery charger to the caravan battery .
2) Where to wire in the positive and negative wires that attach to the leisure battery. Even though I don't intend to use a 12 volt battery often, I still wan't the facility to do so. The new power supply will charge a battery as well.
I can't see why you wouldn't want to have your charger connected to the battery all the time , that way you have a fully charged battery ready for when the site electrics trip out , it would also help to keep your battery from dying through lack of charge . 
In both my caravans they had plastic block connections that had a number of wires going into them , they seemed ok to me and didn't work loose , you could always solder the wire ends together and then fit into the block .

I hope my words come over correctly ie in a helpful way , not a nasty way , as i can't find other words to say what i mean .

http://www.volvoclub.org.uk/towbar_electrics.shtml

atb

Wizard

this may help..........

http://www.kampenwagen.co.uk/Wiring%20diagram.htm

Quote: Originally posted by tonyman on 07/2/2007

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The more I think about it, the more obvious it seems that I wire the positive and neutral of both the vehicle battery and the leisure battery leads to the positive and neutral of the new power supply....hope I'm right!

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Both the charger and the 12S charge from the car need to reach the battery BUT they should be switched so you get one or the other. This is normally done by the Car/Caravan switch on a control panel.

If both are connected together then the system works but if using the van charger the 12S charge pin outside will be live, if this pin shorts out for any reason it will cause problems?. If the 12s is connected to the car with the engine switched off it can draw from the car battery which is still no good, with engine running it's trying to pump voltage into the charger the wrong way!! (just thinking how yours overheated??)

Connections particularly the earth return wires are normally connected together into a single connection block, after all there is only one earth!!. Same goes for the live but each output should be fused to suit the appliance it is connected too.

So you need to get a control panel with this car/van switch and connect the charger to one side and the 12S charge to the other. A simple control panel will also have a few fused outputs for your various bits so this just leaves the earths connected together as they are now which is fine.... as long as they are good connections!