I brought my 540 home yesterday in readiness to pack it this week for the off next Saturday. The van is one I bought in Holland at the back end of last year and, apart form the one night in Dunkirk on the way back, I haven't had the chance to use it. Electrically, it is set up with a BIP and a charger and I've added a Motor Mover since. When I bought it, it had no battery. I fitted the battery yesterday and used the mover to get it into my drive. I then plugged the mains in having checked the charge in the battery before and after to prove the charging system was working. Everything fine. I've gone out to it this morning and can see the battery is fully charged but the BIP is making a constant buzzing noise. Relatively loud. Is this known behaviour from a BIP, do others experience it? Of course, what I don't want to do is set off to France and have it fail on me whilst I'm away. I don't think I realistically have any time to make any major changes to the electrics before I leave (though I know there are options to replacing a BIP if need be..)

Any help or observations gratefully received!

Oh, and if it's relevant, the battery is showing 13.94 volts this morning

ours buzzes but not too loud can hear it now sat over it, someone once said tighten all wires in bip, (without power connected,) just incase one wire is loose,
Arron Calder has more experience of the bip woes than me, and wrote up his whole experience of the bip which am grateful for..
remember something about charger going off, and the short term solution perhaps long term was to invest in a separate battery charger.
mines showing 14volts with our solar's x regulator fitted but at night is around 13.7volts 13.6volts on hook up if that helps..
enjoy your hols

Well, I've got to the bottom of it! A pal dropped by who as well as being a caravan owner, was an electronics engineer in an earlier life. I had already worked out it was the transformer in the BIP that was humming and when we took the cover off, it was no surprise to see the transformer covered in rust and the buzzing coming from the rusty plates.. We sat down and looked through the wiring diagram and my pal immediately recognised that there are basically 2 12 volt circuits - one coming from the transformer and one supplied from the battery. As I will always be on hook up and I have a battery in case I am ever off grid for a short period of time, my pal suggested that the transformer output was, in effect, redundant. So, we simply removed the live (mains) feed to the transformer. And that was it! I had shown him the Aaron Calder article on BIP upgrade, which rather supported his views on what was going on and we will carry that out when I'm back from France.

Everything still seems to work ok without the transformer outputting 12 volts so I'm totally happy that I haven't affected anything. This will only work, however, if you have a battery and a battery charger in the circuit.

thanks for updating
transformer covered in rust!!! is this a water ingress or just natural condensation
all adds to the knowledge base, and confirms why I make the tea and let someone else deal with the tronics

Condensation, I'm pretty sure. My pal didn't have too high an opinion of the electrical design that had been used and was more that happy to help me with the update that will take place. I'll post a report on that when we've done it...