I own a RHD 2004 Ducato 2.8 JTD motorhome on which I recently changed the starter battery.
When I got the old battery out I found a 12v + cable just floating around between where the side of the battery had been and the inside of the offside inner wing.
The cable (which is red in colour) had no connector on it and I could see that the end of the cable was burned as if it had been shorting out somewhere.
As I couldn't locate anywhere where the cable had been previously fixed I isolated it with tape and fitted and connected up the new battery.
The engine started and ran perfectly.
I have been worried where this cable should have been so I untaped it (with the new battery still in place) and checked with a multi-meter to establish if it was live or not - it was.
A visual check showed that the cable ran FROM some sort of connection block situated on the body of the vehicle about 4 inches just above and to left of the battery.
I read somewhere that these vehicles have an emergency battery isolation (intertia switch) located somewhere near the battery and wondered if this is what the connection block is. But if it is that doesn't explain why the engine started with a lead hanging off it.
It really is a mystery and one which I am worrying about, so if there is anyone out there who might be able to shed some light on the subject I would be only too please to hear from you.
Thanks

Just a thought,- do you have a large positive terminal plate which clips onto the top of your battery containing heavy fuses? Is there a broken ring Terminal anywhere on that. It can be a struggle to remove and replace the heavy battery and if it snags agains some cabling whilst doing so, a cable Terminal might get broken.

blaven said:

Just a thought,- do you have a large positive terminal plate which clips onto the top of your battery containing heavy fuses? Is there a broken ring Terminal anywhere on that. It can be a struggle to remove and replace the heavy battery and if it snags agains some cabling whilst doing so, a cable Terminal might get broken.

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Thanks for your reply, much appreciated.
There is a large flat terminal block attached to the + terminal on the battery which I had to remove when I recently changed the battery. On my vehicle there are no fuses on it, just ring connectors with cables attached.
Like you my first thought was that this 'floating' cable had come off there but there where no spare ring connectors on the plate, and the cable is already carrying a 12 volt + at battery potential, so I couldn't think of a reason why they would return it to the + terminal on the battery.
I'm totally flummoxed.

I'm just wondering if this cable is anything to do with the additional chassis battery location beneath the drivers seat. Don't know if this applied to all X244, which I think yours is, but mine does have additional wiring allowing the conection to another chassis battery (not leisure as I once thought). Might be worth a peep inside the seat box, perhaps someone fitted another battery in there, doubtful, but if there is heavy duty wiring inside it must be incorporated in the vehicle wiring somewhere.
HTH

archemedes said:

and the cable is already carrying a 12 volt + at battery potential,

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You mentioned that it was connected to a terminal block mounted on the inner wing. This is a popular location for converters to mount electrical equipment and AFAIK this block is not original Fiat so I suspect that the cable is getting the 12 volts from the habitation battery (you could easily check this by disconnecting the habitation battery)

This doesn't solve the question of what it is for, though it might have been part of the split charging system (check whether or not the alternator is charging the habitation battery to confirm this)

Crossingkeeper said:

You mentioned that it was connected to a terminal block mounted on the inner wing. This is a popular location for converters to mount electrical equipment and AFAIK this block is not original Fiat so I suspect that the cable is getting the 12 volts from the habitation battery (you could easily check this by disconnecting the habitation battery)

This doesn't solve the question of what it is for, though it might have been part of the split charging system (check whether or not the alternator is charging the habitation battery to confirm this)

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I admit that it did cross my mind that the cable might have something to do with the split charging.
I do know that with the engine running the starter battery is charging, as the voltage shot up from 12.6v to 14.10 v with the engine revved up.
What I don't know is whether this cable is part of the habitation battery charging circuit, so I will have to check that out somehow.
Thanks

lancepar said:

I'm just wondering if this cable is anything to do with the additional chassis battery location beneath the drivers seat. Don't know if this applied to all X244, which I think yours is, but mine does have additional wiring allowing the conection to another chassis battery (not leisure as I once thought). Might be worth a peep inside the seat box, perhaps someone fitted another battery in there, doubtful, but if there is heavy duty wiring inside it must be incorporated in the vehicle wiring somewhere.
HTH

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Thanks for your reply.
I have got 2 habitation batteries under the passenger seat in the cab which I am sure charge up when the MH is on 240 volts.
What I dont know is whether the habitation batteries are charging from the alternator, which is something I'm going to have to find out.
I am thinking that if they are not charging then maybe that odd flying cable should go onto the starter battery.
I think that I am going to disconnect the habitation batteries to establish if the 12 v potential on the mystery cable disappears. If it does, then it is odds-on that it is part of the split charging circuit.
Thanks

...first, if you can get to the leisure battery(ies) check the voltage without and with the engine running.

If they are receiving alternator charge, the voltage should rise almost immediately from c12.6v to North of 13.7v.

If you see no change, then (since it is 99.99% certain they should be charging from the alternator) I would definitely suspect the the lead as being part of the split-charge arrangements.

Another thing occurs to me and that is (I think) that in a properly configured split-charge system, the leisure batteries should only be connected when the engine is running (split-charge relay operated) - you might want to check whether the floating lead has voltage with/without the engine running.

HughJampton said:

...first, if you can get to the leisure battery(ies) check the voltage without and with the engine running.

If they are receiving alternator charge, the voltage should rise almost immediately from c12.6v to North of 13.7v.

If you see no change, then (since it is 99.99% certain they should be charging from the alternator) I would definitely suspect the the lead as being part of the split-charge arrangements.

Another thing occurs to me and that is (I think) that in a properly configured split-charge system, the leisure batteries should only be connected when the engine is running (split-charge relay operated) - you might want to check whether the floating lead has voltage with/without the engine running.

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Thanks for the input.
There is definitely a 12v + potential on the floating cable with the engine off.
This rises to the same potential (14.1 v +) as the starter battery with the engine running.

archemedes said:

I am thinking that if they are not charging then maybe that odd flying cable should go onto the starter battery.

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Lol, only if it is routed via a split charge relay, as mentioned by Hugh, otherwise when parked up for the evening off hook-up you might run the starter battery down beyond a point where it is happy to crank the engine.

Crossingkeeper said:

Lol, only if it is routed via a split charge relay, as mentioned by Hugh, otherwise when parked up for the evening off hook-up you might run the starter battery down beyond a point where it is happy to crank the engine.

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This is really a nightmare situation.
Am I correct in saying that if this cable has anything to do with split charging the habitation batteries when the engine is running then when the engine is not running there should not be any + voltage on it?
How about this scenario, what if that connection block I described earlier is really a split charging relay and that loose cable has broken off a lead to the habitation batteries?
The only way that I'm going to sort this one out is to find out if the habitation batteries are charging when the engine is running which will have to wait for a day when it's not pouring down outside.

lancepar said:

I'm just wondering if this cable is anything to do with the additional chassis battery location beneath the drivers seat. Don't know if this applied to all X244, which I think yours is, but mine does have additional wiring allowing the conection to another chassis battery (not leisure as I once thought). Might be worth a peep inside the seat box, perhaps someone fitted another battery in there, doubtful, but if there is heavy duty wiring inside it must be incorporated in the vehicle wiring somewhere.
HTH

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There is only one starter battery on my motorhome. The other two which are situated under the passengers seat are both 110 Ah habitation batteries.

What model of motorhome is it?

HughJampton said:

What model of motorhome is it?

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It's a 2004 Hymer C546 with a Fiat 2.8 JTD engine

archemedes said:

Thanks for the input.
There is definitely a 12v + potential on the floating cable with the engine off.
This rises to the same potential (14.1 v +) as the starter battery with the engine running.

Click to expand...

archemedes said:

This is really a nightmare situation.
Am I correct in saying that if this cable has anything to do with split charging the habitation batteries when the engine is running then when the engine is not running there should not be any + voltage on it?
How about this scenario, what if that connection block I described earlier is really a split charging relay and that loose cable has broken off a lead to the habitation batteries?
The only way that I'm going to sort this one out is to find out if the habitation batteries are charging when the engine is running which will have to wait for a day when it's not pouring down outside.

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I had thought that the cable was connected to the habitation batteries but as you are reading alternator voltage on it this suggests that (a) it is the feed from the split charge relay to the habitation batteries (but disconnected from them) or (b) it is a supply from the habitation batteries to an accessory that was removed by a previous owner when they sold the van on (with the split charging system working correctly)

Really, as you mentioned, the best way forward now is to first measure the voltage at the habitation batteries with engine running then disconnect these and see if that cuts the supply to the cable.

Crossingkeeper said:

I had thought that the cable was connected to the habitation batteries but as you are reading alternator voltage on it this suggests that (a) it is the feed from the split charge relay to the habitation batteries (but disconnected from them) or (b) it is a supply from the habitation batteries to an accessory that was removed by a previous owner when they sold the van on (with the split charging system working correctly)

Really, as you mentioned, the best way forward now is to first measure the voltage at the habitation batteries with engine running then disconnect these and see if that cuts the supply to the cable.

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Yes I agree, that's the next move as soon as the weather improves.
I popped into the MH today and briefly started it up which went ok.
I checked all the ancillaries but not the habitation batteries as they are currently being charged via a 240 volt input.
Surprisingly I found that the horn is not working which it definitely was when it had its last MOT in June.
This is yet another avenue to explore.
In the meanwhile I have ordered a Ducato 2 Service and Repair Manual on DVD which hopefully will shed some light on my problems.
Thanks for your valuable input.

The only other thing I can think of is a battery-to-battery device, installed to keep the vehicle battery "topped-up" from the leisure batteries.

Something like a CBE CSB-2 or a Battery Master.

These would allow current to flow from the leisure batteries under controlled circumstances

Hopefully I will be able to check out most of the possibilities tomorrow.
Thanks for your input.

You must have quite a big passenger seat as my Kontiki has 2 habitation batteries as well but only one under passenger seat and one under drivers.
Looks like the one under passenger seat is goosed as the terminal came off when I touched it and battery is flat. Not happy with wiring connectors on this as well. Looks like system needs a good check over. Its got a Solar Panel on the roof too and its turned off...

Remove the wire and forget about it.

If all the electrics are working as intended then it's most likely either something that a previous owner fitted and a subsequent owner removed but not fully or something the manufacturer fitted but was removed by a previous owner. because it was redundant Another possibility is just bad wiring, the wiring in my camper, while factory fitted looks like something an apprentice fitted on their first day at work, it's an untidy mess.