Technical Alternator fuse

[scottalej]

Batteries not charging off alternator, idle speed higher than normal and oil light flickering (NOT flashing) occasionally. 2003 Ducato x244 2.8jtd motorhome. New alternator and reconditioned Elektroblock 2 years ago. Just had welding done and, although it shouldn't have caused any issues, I'm thinking that the alternator fuse might have blown. Any other suggestions? TIA

 

[Communicator]

Batteries not charging off alternator, idle speed higher than normal and oil light flickering (NOT flashing) occasionally. 2003 Ducato x244 2.8jtd motorhome. New alternator and reconditioned Elektroblock 2 years ago. Just had welding done and, although it shouldn't have caused any issues, I'm thinking that the alternator fuse might have blown. Any other suggestions? TIA

On the x244 alternator fuse should be a 125A (pink) Midi fuse. The fuse is located in the battery fusebox, info that I have suggests that it is the one closest to the battery positive terminal. Should be easy to check after unclipping cover, but disconnect battery negative first.

Unfortunately there are lots of anecdotal stories about stray welding currents damaging alternator diodes, so best to disconnect battery negative as a precaution prior to welding.

If the alternator fuse has blown, then it would suggest that at least some of the alternator diodes have been damaged. It may be possible that these could be replaced. I have done a similar repair, but that was a very long time ago.

Another item to look at is the warning light for which Fiat use a battery icon. If the light does not illuminate with ignition on, then it coud mean that the alternator regulator has been damaged, but do also check 10A fuse F37 in LH Cab fusebox. While not shown on the diagram this fuse is also essential for main beam headlights, so a quick check for the fuse would be to try the headlights.

Perhaps TIA is your normal complementery close, but please post on this thread to tell us what you have found. It could help others in the same situation.

 

[ZaphodB]

and oil light flickering (NOT flashing) occasionally.

This is a weird symptom, does it flicker at a different rate if revs are raised ?

...and does the battery voltage change (at all) when running ?

 

[scottalej]

Thanks. I didn't see a fusebox near the battery but I'll have another look. There's a big board with multiple fittings on the positive connector and 3 fuse holders situated above it.

 

[Communicator]

Thanks. I didn't see a fusebox near the battery but I'll have another look. There's a big board with multiple fittings on the positive connector and 3 fuse holders situated above it.

The battery fusebox on x244, and later Ducato models is attached to the battery positive, with stabilising metal clips to the case. The cover is retained by two plastic clips. It is your "big board".

 

[scottalej]

The battery fusebox on x244, and later Ducato models is attached to the battery positive, with stabilising metal clips to the case. The cover is retained by two plastic clips. It is your "big board".

No cover on it which threw me. Battery light comes on with ignition. Full beam working. On a camp site tonight so on hook up. Leisure battery is charging but not the engine battery.

 

[Communicator]

No cover on it which threw me. Battery light comes on with ignition. Full beam working. On a camp site tonight so on hook up. Leisure battery is charging but not the engine battery.

Does the starter/engine battery normally charge when on EHU? What is the make of the habitation electrical system? e.g. Sargent, CBE, Schaudt etc

 

[scottalej]

Does the starter/engine battery normally charge when on EHU? What is the make of the habitation electrical system? e.g. Sargent, CBE, Schaudt etc

Yes it does. It's a Schaudt

 

[Communicator]

Yes it does. It's a Schaudt

The lack of starter battery charging means that you are runnung the engine from the battery. When the battery becomes discharged............ I hold diagrams for several different versions of the Electroblock. The Electroblok model number will allow me to select the correct diagram, if it is in my library.

 

[scottalej]

The lack of starter battery charging means that you are runnung the engine from the battery. When the battery becomes discharged............ I hold diagrams for several different versions of the Electroblock. The Electroblok model number will allow me to select the correct diagram, if it is in my library.

EBL 100.
I was able to charge the engine battery with a separate charger last night.

 

[Communicator]

EBL 100.
I was able to charge the engine battery with a separate charger last night.

I was thinking about changing Batt1 & Batt2 connections on rear of EBL, so that engine battery was charged in place of hab battery. This would probably provide more current to starter battery than most separate chargers.
As away from home you presumably have reduced access to tools/ test instruments.
You confirmed that battery warning light illuminates. I forgot to ask whether it goes out as normal when engine started. If it does go out the the alternator is at least partly functional.
My present worst case scenario is that the alternator has been damaged causing the fuse to blow.

If attempting the following, take extreme care not to short the battery positive to earth.

Perhaps the best way to check would be to bridge the suspected (pink?) fuse with a small test lamp. The test lamp should not light. If it does illuminate, then the alternator is at least suspect. If the test lamp stays dark, then there is some hope.

If the you do not feel competent to carry out the above, do not attempt it.

While the engine battery is not being charged from the alternator, when driving I suggest switching the fridge off, and avoiding using the heater fan and headlights.