HELP. I have just been away for the week end and now have a BIG problem. While I was away I was using an auxillary socket when I shorted it out accidentally. No problem I thought I will just change the fuse. I went to the fuse box but all the fuses were intact but I had no electic at all. I got my meter out and found that with the battery disconected I had 12.6volts. When I reconnected to the caravan wiring I had 4,6volts.When connected to a generator everything worked but on disconnecting back to zero. Also when I got home I tried to use my mover. It engaged the mover but wouldn't move it at all and then wouldn't disengage the mover. I changed the battery for an other one and it moved it a bit then gave up. It did disengage though.I know a little about electrics but this is way over my head. I am thinking that the caravan 12v circuit board is suspect but I don't want to change it and then find I still have the same problem. Anyone know a good caravan electrician in the Midlands ( Walsall) Nigel
Was the second battery fully charged? A fully charged battery should be 12.8v at 12.4v it's only 75% charged.
A motor mover demands a lot of power to overcome the inertia.
Before I did anything else I would try with a fully charged healthy battery.
When you dead shorted the battery you may have buckled the plates.
Saxo1
If you are confident that you short circuited the auxiliary power supply then it should have blown the fuse without any question, that's exactly the purpose of why fuses are installed but you need to check whether the right amp rating fuse is installed. If the rating should be say 10 amp and you have a 20 amp fitted then this is the reason why it failed to trip the fuse and protect the circuit. As the fuse didn't blow then I will second the answer that the problem is with the leisure battery. The acid inside keeps the lead plates cool but if a surge of heat has been inflicted then the plates could have sizzled and warped thus making the separated plates make contact which in turn short circuits the battery thus giving you only 12.6 volts. The battery will now most probably fail to hold a charge so you need to replace the leisure battery and identify all the fuses to ensure that each and every one are the correct rating. As mentioned, a motor mover takes a lot of power so you need a fully charged battery when ever you intend to use it. Also, a low battery can cause the water pump to activate even when the taps are not turned on and this will also drain the battery very quickly.
Thanks for your replys. I have tried a new good battery and still nothing works. If I had fried the batterey the new battery should allow all the other systems to work and it doesn't. This why I suspect the circuit board. Nigel
With the battery disconnected you should check for continuity between the pos and neg cables. This will rule out a dead short within the vans wiring/circuits should it not be present. Make sure all 12v systems are off then switch on one by one. If you then see continuity, you will know which circuit is at fault. You must also drop test the battery to determine good or bad. You should have a remote fuse located near to the rear of the battery box, inside the van this should be rated at 20amps.
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Thanks for everybodys help. I have fixed the problem. I removed all the fuses and put them back one by one in the hope of finding the problem circuit. I got them all back with no problem, even the one I short circuited in the first place. All Ok now . Nigel