# RV/MH electrics - FIRE!!!!!!!!!!!!!!!



## 98064 (Mar 10, 2006)

Hi, first post so any thoughts whilst I drink beer and contemplate in advance of a lot of crawling around in the cold tomorrow?

We bought an older Dodge based RV late last year, few things to sort out here, odd battle scar there but we love it. Anyway, we 'excersize' the old girl regularly and last time out I noticed the dash charge guauge suddenly started showing a substantial discharge. Now I assumed something to do with the split charge widget and, thanks for the advice Steve at RV Maintanance, disconnected our known dodgy leasure battery to test, well disconnected the -ve as the positive is difficult to reach especially in the dark. Well, driving the beasty home just now all seemed well again until guage suddenly goes to heavy discharge , b****r probably not the split charge doings then. I'm getting to the fire bit..... 
So on the wall at the back is an old torch holder/charger (guess as there is nothing in it), well with the gauge showing the discharge I lifted the revs up to see if it was just because the engine was at idle, corner of my eye I first saw a spark then this torch holder thing burst, literaly, into FLAMES! Engine off, and I've not moved that fast in many years! 
Turns out the holder widget was wired to an adjacent light fitting ie 12volt, now here's one question for you all how is the fitting hence the holder seeing 12 volts with the leasure battery disconnected? Next up I put a multimeter accross the two wires and, nothing with the ignition off, nothing with the ignition on, start the engine I've got 30 volts dc that rises with the engine revs, I took it up momenteraly to approx 2500 and the meter showed 50+ volts. 

Any thoughts?

I'm not the sort that's fazed (no pun intended) by electrics there's just a lot of options floating round my head so..........

Cheers, Simon.


----------



## 88927 (May 10, 2005)

Hi Simon and welcome to the site.

My first thought is to get a large fire extinguisher to hand... You sound as though you have got a real strange one there. I do not understand how you have only got voltage with the engine running unless the fitting is supplied by the split charge relay?? And 50 volts??? Are you sure that you are seeing DC or could it be AC ripple that is apparently pushing the volts up. Maybe you are getting power from the alternator, and maybe it is not going through the rectifier stage??? What does the voltage look like on the battery terminals? Are you using a DVM or a moving coil meter?
Have you disconnected the smoked fitting? and if so what is your gauge showing now? I would be very tempted to get an auto electrician to check out the wiring as it sounds as though Mr Bodge it has been playing.....

I know there are no answers here but hopefully I have given you some thoughts...

Keith


----------



## Scotjimland (May 23, 2005)

kands said:


> My first thought is to get a large fire extinguisher to hand...


Spoken like true submariner :lol: :lol:


----------



## Bagshanty (Jul 24, 2005)

... regulator gorn?

To push out the current required, an alternator must have the ability to push sufficient volts to keep the current flowing at that level. Normally the regulator will keep the volts down to 14.2 volts. On open circuit (eg battery removed) and no regulator, the voltage will go as high as it likes. 

Well that's my view, as an ex skimmer!


----------



## 98064 (Mar 10, 2006)

Cheers for responses.

DVM and a fresh one no reason to doubt, many fire extinghishers and yes fitting removed plus wiring removed back to point of splice into loom. I understand alternators but, if the regulator failed just what could the voltage get up to, or, re later posts that's the first test tomorrow in daylight (with the many fire extinghuisher) basically the alternator has to be the favorite start point, combination of time to think on it and a confident sounding post, Bagshanty, thank you.

'till tomorrow, Si.

PS Mr Bodge has had a little go but I'm typically a dab hand at exsorsizing Mr Bodge!


----------



## 98064 (Mar 10, 2006)

*Fixed, well it will be!*

So, in case anyone's interested though worth all bearing in mind.

2 days trying to diagnose
1 voltage regulator 
1 alternator
3 complete examinations of the wiring (dash out etc etc)

Problem, split charger! I'd disconnected the leasure battery circuit and the feed from the alternator but forgot to disconnect the split charger to engine battery connection DOH!!!
Well hey, at least I know I've got a new alternator and regulator plus a good pair of spares and our wirings spot on!

Just need to order a new split charger.

Si.


----------



## 88724 (May 9, 2005)

Hi 

I dont like split charge relays, under most circumstances they are not the way to go, but that still doesnt explain a reading of 50+ Volts


----------



## 98064 (Mar 10, 2006)

50+ volts caused by a short on the split charger, not a dead short as such but a high resistance short if you like and for some reason this caused the alternator to produce daft voltage. Don't know whether this is normal or a quirk of old American units.

Si.


----------

