This is a tricky one- assistance needed

[TCG]

A good friend of mine owns a Duccato 2.3 X290 2016 motor home

Motor home engine started first time after many months sitting on the drive. after about a week or so his engine battery went flat, even while on hook up the battery was less that a year old. Hab batteries fully charged no problem.
Charged up Cab battery - showing 12.7 volts - great - within 5 hours the battery had discharged and was flat again.
battery under warranty - so battery changed for a new one. he put new battery on and overnight the battery discharged and was flat next morning.

Obviously something is draining the battery big style... but what?

Any assistance really appreciated

 

[PJGWiltshire]

Not a real expert but consider this .You will need at Multi meter. And then connect through the negative pole of engine battery on amps. If the battery is being discharged then there will be an amp reading showing draw. The process then is to remove each fuse on the engine circuits( there could be two sets of fuses) one by one until after a removal you hope to see that the Amp reading go to Zero. If you get that you then know what is drawing the amps and thus sort that problem.

 

[berni109]

Process of elimination firstly check battery disconnected then start removing fuses to find the discharge curcuit. To completely flatten the battery overnight I would start with the bigger amperage ones.
Beat me to it but assumed no meter

 

[jockaneezer]

...and check the condition of the van's earth straps, you might want to undo them, clean them up and refit them.

 

[Ingwe]

...and check the condition of the van's earth straps, you might want to undo them, clean them up and refit them.

I need to find out where the earth straps actually are. Not apparent to me just looking into the Peugeuot Boxer engine bay. I assume it requires me to crawl under the van?

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[PhilandMena]

I

...and check the condition of the van's earth straps, you might want to undo them, clean them up and refit them.

How would that cause a drain on the battery ???

 

[jockaneezer]

There will be a cable type one from the battery negative to the van's bodywork and possibly a flat braided wire one from the gearbox to the bodywork. They sometimes get corroded up and go "high resistance" which can lead to lots of problems, especially involving immobilisers.

I

How would that cause a drain on the battery ???

I was (rightly or wrongly) led to believe that a high resistance earth can cause any "usual" battery drains (immobiliser, radio, alarm etc) to draw a higher current ?

 

[autorouter]

If you are going to buy a meter to investigate battery drain, get a clamp meter. This clips around a wire and measures the current drain by sensing the magnetic field that the current generates. No electrical connection required, no disconnecting wires or disturbing the circuit you are trying to measure. Best for beginners and convenient for professionals.

I usually recommend the Uni-T UT210E clamp meter because it has great ability to detect small currents. But this current drain is so large it will show up on any DC clamp meter. Just make sure the meter can measure DC current - quite a few just measure AC, which is fine for house wiring but no good for vehicles. The description often says AC/DC, but usually that's the volts measurement. The amps measurement is usually AC only.

Note that a clamp meter usually has sockets for test leads and can measure volts, continuity, ohms etc just like a normal multimeter. Best of both worlds.

 

[Diabalo]

I can recommend the Uni-T UT210E clamp meter also, great bit of kit just over £30 on fleabay

 

[WynandJean]

I need to find out where the earth straps actually are. Not apparent to me just looking into the Peugeuot Boxer engine bay. I assume it requires me to crawl under the van?

I did that - assumed the battery would be in the engine bay but couldn't find it. It's beneath the passenger footwell under a panel.
P.S. Auto correct thought that should read 'football'!
Wyn

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[Ingwe]

I did that - assumed the battery would be in the engine bay but couldn't find it. It's beneath the passenger footwell under a panel.
P.S. Auto correct thought that should read 'football'!
Wyn

But I'm not looking for the battery but the earth strap. I don't think the thread is talking about the battery earth lead (I may be mistaken). I think the lead I'm looking for attaches the engine to the gearbox somewhere.

 

[Spriddler]

I think the lead I'm looking for attaches the engine to the gearbox somewhere.

An Earth strap is needed between the engine or g/box and the chassis because they are usually on rubber mounts and therefore insulated from the chassis to which the battery's Earth lead is connected. The engine and the g/box are normally bolted together in metal to metal contact anyway so 'Earthing' one automatically earths the other.
A bad Earth connection can drive the current to find an alternative route. E.g. on my Mini with a bad Earth connection due to rust/corrosion so that the Earth return found its way up the choke cable causing it to seriously overheat and set fire to the padded dashboard!

 

[Ingwe]

An Earth strap is needed between the engine or g/box and the chassis because they are usually on rubber mounts and therefore insulated from the chassis to which the battery's Earth lead is connected. The engine and the g/box are normally bolted together in metal to metal contact anyway so 'Earthing' one automatically earths the other.
A bad Earth connection can drive the current to find an alternative route. E.g. on my Mini with a bad Earth connection due to rust/corrosion so that the Earth return found its way up the choke cable causing it to seriously overheat and set fire to the padded dashboard!

Spriddler-do you know where this earth strap is located on a Peugeot Boxer based van? Thanks

 

[Spriddler]

Spriddler-do you know where this earth strap is located on a Peugeot Boxer based van? Thanks

No, sorry. It will probably/should/might be a braided strap maybe 1/2" to 3/4" wide so not difficult to spot and it will be 'on its own' i.e. not within a wiring loom. Some earth straps are just heavy round black insulated cables but the following still applies.........
TBH as a practical chap and to save faffing about with finding, removing and cleaning the existing strap (which will no doubt be fairly inaccessible, filthy/corroded) I'd buy an Earth Strap from a car parts dealer already having connectors fitted on it and fit it as a second one between an accessible and clean engine or g/box bolt and an accessible and clean chassis/body bolt. (You can fit as many earth straps as you like).
Be careful when choosing the engine or g/box bolt that the selected bolt isn't an oil drain plug

Here are pics and details of earth straps:

car earth strap products for sale | eBay

Buy car earth strap products and get the best deals at the lowest prices on eBay! Great Savings & Free Delivery / Collection on many items

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[Diabalo]

As Spriddler says

Fiat X250 DIY supplementary Earth Strap example

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[Ingwe]

Thanks for the useful photo and link. One (hopefully) last question: is there any merit in getting the covered lead rather than the bare strap. Good to know that you can have several earth straps.

p.s. I'm sorry for pinching this thread.

 

[autorouter]

It's easy to check the earth wiring with a meter. Set to the lowest resistance range and touch the probes together. If it's a super meter with a 'zero ohms' function, use that to zero the reading with the probes touched together. If it doesn't have that function, just remember the reading, usually between 0.1 and 0.5 ohms.

Next, touch the probes between the engine metal and an unpainted metal part of the bodywork (the head of a bolt is usually convenient). The resistance should be so small that the reading doesn't change. If you get a change, you have an earth problem between the engine and bodywork.

You can check the earth between the negative battery terminal and the bodywork in a similar way.

 

[TheBig1]

I will go out on a limb and suggest that a sudden high current draw with the engine off could easily be a sticking relay. It can stick closed, but if it sticks open, and the circuit continues to draw high current, the battery will quickly go flat. Maybe the diesel heater circuit for cold starts. Have seen this a few times over the years

 

[Spriddler]

..... is there any merit in getting the covered lead rather than the bare strap.

Nope, none at all. All metalwork of the m/h engine, chassis etc. is at the same potential (i.e. Negative) as the earth strap so it isn't necessary to insulate it except for rare/unlikely situations with which you will not be involved in merely adding a strap. The covered one looks tidier