Cab battery Fuse

[Top Hat]

My cab and leisure battery's are not being charged when the engine is running in my Fiat Ducato.
I have looked today for the alternator/cab battery Fuse with no luck, can anyone point me in the right direction, I have looked at the fuse locations in the book but no mention of this fuse.

 

[Tombola]

check behind the drivers seat in the floor, and under the passngers feet panel coming off the battery.
what year is the van

 

[Two on Tour]

Have you checked the mega fuses on top of your cab battery ?

 

[Top Hat]

It a 2010, I will look at those locations tomorrow.
I have looked at the battery located under the passenger's feet but, I was looking for a standard fuse, will look again tomorrow

 

[Tombola]

It a 2010, I will look at those locations tomorrow.
I have looked at the battery located under the passenger's feet but, I was looking for a standard fuse, will look again tomorrow

just checked behind my drivers seat (sometimes may be behind the cowelling) mine is on the floor and one does say 20a cab battery fuse

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[Landy Andy]

In my 2010 Duc I’ve got some big fuses and wiring under the lower panel behind/beside the drivers seat. The trim panel that cover the seat belt roll and mechanism.

 

[Pausim]

20A and 50A fuses are more likely to be the domestic connection to the engine battery. The main engine battery fuse should be right next to the battery as shown by Two on Tour above.

 

[Tombola]

20A and 50A fuses are more likely to be the domestic connection to the engine battery. The main engine battery fuse should be right next to the battery as shown by Two on Tour above.

that would makse sense as my 20a battery fuse behind the drivers seat in the fuse box is where the van to cab connector is

 

[Top Hat]

20A and 50A fuses are more likely to be the domestic connection to the engine battery. The main engine battery fuse should be right next to the battery as shown by Two on Tour above.

I haven't checked the cab battery fuse yet, I am now thinking because the leisure battery is also not charging the this fuse on the cab battery might not be to blame? might have to look at other thing maybe, split charge relay, alternator etc.

 

[Pausim]

If the charge is not reaching the engine battery it can not reach the leisure battery either, because the connection comes from the engine battery. I would start at the engine battery and work back through the fuses towards the alternator. Once you have sorted the engine battery out the leisure battery charging will probably be ok. The split charge relay should only operate when the alternator is charging the engine battery.

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[denisejoe]

Check the battery clamps was on an aire in Belgium guy next door said goodbye jumped in van and nothing we checked every thing with a multimeter 11.8v on terminals but I checked on the battery 12.7v check terminals pos could just be moved with nut fully tight had to file a bit of the terminal reassembled and all ok

 

[Top Hat]

If the charge is not reaching the engine battery it can not reach the leisure battery either, because the connection comes from the engine battery. I would start at the engine battery and work back through the fuses towards the alternator. Once you have sorted the engine battery out the leisure battery charging will probably be ok. The split charge relay should only operate when the alternator is charging the engine battery.

Thanks for that, in my ignorance I thought the split charge relay did just that, split the charge between the two. I will do as you suggest.

 

[Pausim]

Thanks for that, in my ignorance I thought the split charge relay did just that, split the charge between the two. I will do as you suggest.

I can see why you might think that, confusing terminology. Indeed there are devices that do as you thought, sometimes found on solar and marine applications.

 

[autorouter]

There should be a wire from the cab battery to the split charge relay, with a big fuse (30 or 50A) near the cab battery.
There should be a wire from the hab battery to the split charge relay, with a big fuse (30 or 50A) near the hab battery.
Both fuses need to be OK for the charge to go from cab to hab battery.
There is probably another wire from the cab battery, with a 20A fuse, for the 12V fridge heater element.

At the split charge relay, the voltages of the two power terminals should be identical to the two battery voltages. They will no doubt be slightly different, so you can check which is which. When the engine is running, the voltage of the two power terminals should be exactly the same as each other.

 

[Pausim]

Both fuses need to be OK for the charge to go from cab to hab battery.
There is probably another wire from the cab battery, with a 20A fuse, for the 12V fridge heater element.

The trouble is the OP reports that neither his cab battery or hab battery is being charged. I am suggesting that until the cab battery charging problem is resolved he has no way of telling if the hab system is working. My guess is that when the cab (engine) battery problem is resolved his hab (leisure) battery problem will also disappear.

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[autorouter]

The trouble is the OP reports that neither his cab battery or hab battery is being charged. I am suggesting that until the cab battery charging problem is resolved he has no way of telling if the hab system is working. My guess is that when the cab (engine) battery problem is resolved his hab (leisure) battery problem will also disappear.

I think you're right about that. I'd like to know if the cab battery is actually not being charged, or is it maybe a control panel or indicator showing a misleading reading. What's needed is a direct multimeter voltage reading at the battery terminals, with the engine stopped, and with the engine running. That will show if the battery is being charged by the engine.

The cab battery should always charge from the engine/alternator, whatever the state of the fuses to or from the split charge relay.

 

[Top Hat]

I think you're right about that. I'd like to know if the cab battery is actually not being charged, or is it maybe a control panel or indicator showing a misleading reading. What's needed is a direct multimeter voltage reading at the battery terminals, with the engine stopped, and with the engine running. That will show if the battery is being charged by the engine.

The cab battery should always charge from the engine/alternator, whatever the state of the fuses to or from the split charge relay.

Tested both the cab and leisure battery's with a multi meter and both are being fully charged through the solar panels (cab by means of a linked battery master) and they both correspond with the panel, as soon as I start the engine both reading fall.

 

[Top Hat]

When I say both fall I mean they are on float charge approx 13.8v leisure and 13v cab, when engine is started both drop to approx 12.6v

 

[Pausim]

When I say both fall I mean they are on float charge approx 13.8v leisure and 13v cab, when engine is started both drop to approx 12.6v

Does your van have a smart alternator?

 

[Top Hat]

Sorry I don't know, I've had the van for 30 months with out any problem in this area.
Before the problem when the engine was started the voltage jumped to approx 14v to the cab battery.

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[autorouter]

If the cab battery is not being charged by the alternator, then it's either a bad connection (including earth strap), blown fuse, bad alternator or a smart alternator that's working as intended.

There will be practically zero volts across a properly working fuse, when the engine is running or not running. If the cab battery positive post is like the pic in post #3, then it's one of the two big fuses, maybe someone knows which one of those goes to the alternator.

If the fuses are good, then you can check the earth strap by connecting a jump lead between the battery negative terminal and a solid metal contact on the engine somewhere. If it works OK with the jump lead connected, then it's an earth strap problem.

If not the above, then it's looking like an alternator problem, especially if you can find out if it's a smart alternator or not.

 

[Top Hat]

If the cab battery is not being charged by the alternator, then it's either a bad connection (including earth strap), blown fuse, bad alternator or a smart alternator that's working as intended.

There will be practically zero volts across a properly working fuse, when the engine is running or not running. If the cab battery positive post is like the pic in post #3, then it's one of the two big fuses, maybe someone knows which one of those goes to the alternator.

If the fuses are good, then you can check the earth strap by connecting a jump lead between the battery negative terminal and a solid metal contact on the engine somewhere. If it works OK with the jump lead connected, then it's an earth strap problem.

If not the above, then it's looking like an alternator problem, especially if you can find out if it's a smart alternator or not.

Interesting, so if I disconnect the batteries from the solar panel and discharge both batteries, when the engine is started if they then start charging this will indercate a smart alternator

 

[2bob]

any more news on this as mine gone same way mh sundance 2005

 

[Top Hat]

I plan on doing some investigation on Saturday, to busy at the minute, just as well we can't go out anyway.

 

[2bob]

thx

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[Top Hat]

Have you checked the mega fuses on top of your cab battery ?

View attachment 470063

How would I recognise a blown fuse on the 4 fuses shown (same setup as mine) I presume I have to remove the fuse (no sign of burn on the top) and inspect the bottom, will the large one be from the alternator.
Yesterday I confirmed the alternator is not smart (we have something in common) looked at 1or2 other things and got called away so will check out connections and fuses next week

 

[Two on Tour]

How would I recognise a blown fuse on the 4 fuses shown (same setup as mine) I presume I have to remove the fuse

Leave the fuses in situ and use a multi meter that has a "continuity" mode (where the arrow is pointing on my meter)and measure across the fuse.
A blown fuse will register 1 and good fuse will register all zeros or very close to that, and if your meter has a buzzer, the a good fuse will buzz and a blown fuse will not.

 

[autorouter]

How would I recognise a blown fuse on the 4 fuses shown (same setup as mine) I presume I have to remove the fuse (no sign of burn on the top) and inspect the bottom, will the large one be from the alternator.

There's no visual indication on this type of fuse. Disconnecting the wire and checking with a meter is the only sure way.

Alternatively for a quick check, the voltage across the fuse terminals should be approximately zero. So if you measure it as 12V, or anything other than zero, then you can be sure the fuse has blown. This test doesn't always work - you can sometimes read zero volts across a blown fuse.

There are two sizes: Mega fuses are 51mm between centres, and Midi fuses are 30mm between centres.

MEGA fuse (40 - 500 Amp rating)

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www.altecautomotive.co.uk

Midi Link Fuses

Midi link fuses used for protecting larger current circuits in automotive, marine and leisure applications. Available in current ratings from 30A to 150A.

www.12voltplanet.co.uk

 

[Top Hat]

Thanks all, all fuses are good, 001 and accompanied by buzzing, removed and cleaned up earth strap and terminals, ran battery down to 12.1 still no charge so not smart.
Have now booked into a auto elec, will report back if it is indeed the alternator

 

[Itsmcb]

I've found this interesting, any solution yet?

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