Technical No start but a buzzing sound

[Barry webb]

Hi this is my first post i have a 1999 fiat ducatto 2.5 tdi motorhome for some reason it's developed a problem.
When i turn on the ignition I get the battery light on the dash bright and the other lights like glow plug lights are very dim and a buzzing noise can be heard.
On trying to crank the engine it makes all strange electrical noises and won't start.
If I disconnect the leasure battery and try to crank it it does nothing.
When i try to turn the blower fan on it also make a strange sound and even the lights sets the buzzing off.
If anyone out there can help as I can't get a auto electrician for 3 weeks.
Barry

 

[Communicator]

Hi Barry,

Welcome to the forum.

1. You say that nothing happens when your habitation battery is disconnected. May I suggest that as a precaution, you leave the battery disconnected until your problem is resolved. It sounds as though your habitation battery is trying to power the vehicle system. This should not happen, but if a split charge relay is energised via ignition on, rather than from D+, then it will happen. If the hab battery is powering the vehicle system then it is possible to seriously damage parts of the habitation electrical installation.
2. What is the state of charge of vehicle (starter) battery?
3. Check condition of starter battery negative and earth connections
4. With starter battery negative disconnected for safety, check that main positive connections are clean, and firmly tightened.
5. Are the starter battery cable connections original, or have they been replaced with a type that has screw clamping for the cables? Internal corrosion can occur.

 

[Barry webb]

Hi thanks for your help my leasure battery is a lithium 12v 300ah would that make any difference.
My wife has now told me to stop playing with the van of fear of a electrical fire and I don't have any insurance to be working on it.
If something happened I would lose the lot.
Barry

 

[The Panda Nut]

I suggest she is right unless you know what you are at it sounds like a job for a mobile auto electrician and I suspect its something easy to identify with the right test gear. Even the leisure battery sounds like an expensive thing to damage. If you want to remove the batteries and take them to a battery specilist and get them tested this would be a simple and safe start.

 

[Communicator]

Hi thanks for your help my leasure battery is a lithium 12v 300ah would that make any difference.
My wife has now told me to stop playing with the van of fear of a electrical fire and I don't have any insurance to be working on it.
If something happened I would lose the lot.
Barry

As you have a lithium based habitation battery, there should be a B2B (Battery to Battery charger) to provide the correct charging profile.
However I have seen lithium batteries offered as a "drop in replacement" for a lead acid battery.

If a B2B is fitted then either any split charge relay should have been disabled, or modifications made so as to prevent the split charge relay, and B2B operating in parallel, with the split charge relay effectively shorting across the B2B input and ouput positive terminals.

I would not expect a B2B to pass power towards the starter battery, but a battery master or similar device may do this, particularly if solar panels are fitted.

As I previously suggested, keep the negative of your lithium battery disconnected, until fault is cleared.

I advise against creating matrimonial disharmony.