2000 Winnebago Journey battery problems

[Scotsman]

I live in UK and have above rig........Whilst on holiday in Devon recently whilst on plug in i noticed that house battery was getting hot and smell of sulphur coming from it......called breakdown, and guy said battery u/s and needed replacing....replaced it with new one, and immediately the 2nd one started getting hot..........On trip down south, i noticed ammeter on dash was right up just below the red box,(if that means anything to anyone)....To cut long story short, both batteries were replaced,and situation norm returned.......One returning to scotland, i had to park up (wildcamp) as it was too late to return rv to its storage facility. I stopped the engine, and attempted to start onan genny(in nose) from the control panel in rv......looking forward, i could see the green light on rocker switch on dial flashing,which it usually does till genny fires up and goes solid green.....all of a sudden it stopped flashing,the inverter housed in cabinet next to tv let out a screeching noise then nothing.......now lights wont work...carbon monoxide alarm on floor which has green warning light went dead......fridge conked out.......when i check battery levels on control panel,chassis batteries are showing good charge.....but when i put to house batteries the screen just goes clear.......nothing showing at all........Worringly, i could also start genny from engine b4....i tried this last night,and nothing.......the light on genny switch just doesnt come on...dead as a dodo......Anybody please have any ideas????????....PLEASE.

[doc]

I might start by removing the battery cables and thoroughly cleaning the connections. I my experience, most 12 volt electrical problems can be traced back to some sort of ground or connect problem.
Are you sure the batteries were installed the way the old ones came out? Did all the 'smaller' wires attached to the positive posts get reattached when new batteries went in? I had one that when the new batt was placed, the small wire fell behind it. Found it when I was going over a diagram I had made before removing the old ones.
good luck

[Scotsman]

I'll need to check that again.......but first look everything looks attached and tight.......mere fact theres nothing at all makes me think a fuse or relay has went somewhere........but i dunno enough about it to know where to check........