Voltage On Fiat Ducato Engine Bay Positive Battery Point

[davida71uk]

Hi Everyone. We had an issue with our starter battery over the weekend, an unexpected voltage drop with a Vanbitz Battery Master (I need to call them to check this) meant I had to jump the engine battery. The Victron Smartshunt had %89 and 12.2v on the Leisure batteries (it had been in covered storage since 26.03.2022) but the starter battery was down to 11.2v (beyond the .7v difference) and couldn't crank the engine. I used a Norco pack on the starter battery and got the van started.

The issue I had was that I had to connect the Norco pack directly to the battery under the passenger side floor as I couldn't jump the battery from the terminal in the engine bay. With a voltmeter directly on the engine battery it was 11.2v pre-jump which was the same as the habitation panel (listed as 'fair'). When I tried to use the Norco and also jump leads on the engine bay points nothing happened.

I checked the voltage on the engine bay positive point and it was negligible. The reading didn't change beyond a background fluctuation. The question is, should I see the same voltage on the engine bay positive point as I see directly on the battery? If I don't, as is the case, does that mean the engine point may be disconnected from the battery? Has anyone ever measured the voltage on that positive engine bay point?

Thanks.

 

[Mixyblob]

It sounds like you might have a high resistance connection between your battery terminal and the connector that feeds the remote positive jumping terminal.

 

[Phill D]

The short answer is yes.

 

[davida71uk]

Okay, thanks, need to get that checked. I also called Ian at Vanbitz and 12.2v is the floor at which the Battery Master won't send a trickle charge to the engine battery, to save a leisure drain.

 

[Burgo]

When I jump started ou r ducato the underbonnet positive had 12v +. Are you sure you had the other test lead on a good earth - if you dabbed onto something mounted on antivibration mounts, or on a non conducting sub assembly you'd get a low or negligible reading.

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[davida71uk]

I think so, I used the earthing point in the engine bay, the central plate with the black wire.

 

[TheBig1]

check the voltage under the bonnet with the engine running. It should show a healthy charge going to the battery. If not, it may be one of the fuses on the battery terminal under the floor has failed

 

[GeoffnDee]

It would also be worth checking the 2 x earth lead connections are clean and tight , engine to body and battery to body.
The jump start point under the bonnet should be the same voltage as the starter battery under the floor.

 

[Stealaway]

Is there a lot of paint on the earthing stud insulating it?

 

[davida71uk]

Is there a lot of paint on the earthing stud insulating it?

No, bare metal, all clean.

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[Off da Grid]

I always attach the Earth jump lead to the big fat engine lifting eye.

 

[davida71uk]

I always attach the Earth jump lead to the big fat engine lifting eye.

Is that bare metal? Can you post an image please?

 

[Mr David]

Might this Motorhome thread be of use?
https://www.motorhomefun.co.uk/forum/threads/fiat-ducato-charging-problem.227995/#post-4343782

 

[davida71uk]

Might this Motorhome thread be of use?
https://www.motorhomefun.co.uk/forum/threads/fiat-ducato-charging-problem.227995/#post-4343782

Hi Mr David, not really, charging is not the issue, at least when the engine is running, it's outside on solar or on hook up. My battery master and B2B charger are all working correctly. I do have an issue with storage drain but then we did leave it under cover for 4 weeks.

The issue is testing and jumping from the points in the engine bay vs. directly to the battery. I posted another thread a while back about a rogue connector swinging in the air near the engine bay positive terminal. I cannot be sure as it goes into conduit behind the air intake but I think that black wire and connector is the earthing point wire on the plate that every video seems to have someone connecting the negative jump lead to.

I've not looked again but am interested in this "big fat engine lifting eye." that Off da Grid commented about.

 

[davida71uk]

Thanks everyone for the replies, I am sorted. I earthed my tester to a lifting eye on the block and got a solid 13.0v-13.1v. So it must be that plate is not earthed correctly.

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