Split charger problem

[ninja.turtle007]

The trigger wire on the split charger was spliced into the wire running from the ignition to the diesel pump. Shouldn't it be from the blue alternator wire?

Anyway it has been all working fine until last week when the trigger wire melted! At the same time the van kept conking out. I removed the trigger wire and rejoined the pump wire and all seems to be good. What do I need to be checking or replacing within the split charging system? Or was the melt wire due to a bad connection to the pump?

Thanks

Tom

[ewenmaclean]

Hello,

the split-charge relay should indeed be fed from the blue exciter wire. I would check the wire you're talking and earth definitely go to the 85/86 pins, and there's a big fat wire going from the starter battery positive to the leisure battery positive.

If it's all ok I can't imagine why you'd melt that wire - the solenoid in the fuel pump shouldn't take too much either, but I'm not sure of your set up. On mine the ECU controls the shut-off solenoid and so problems like that can be more complicated.

Good luck sorting it out

Ewen

[Oldiebut goodie]

I would just replace the split charge relay with a voltage sensitive one then you will not have to worry about where to splice into the loom as it is triggered by the battery voltage rising. Seems stupid to me to interfere with the fuel cut off solenoid like that.

[California Dreamin]

If it's all ok I can't imagine why you'd melt that wire -

Good luck sorting it outEwen

There is a subtle but vital difference between taking the feed from the 'exciter' wire and diesel pump shut off solenoid.
The exciter feed only trips the relay AFTER the engine starts.

Think about it....taking the feed from the pump means as soon as you turn the ignition on the potentially 'flat' leisure battery is linked to the charged starter battery so sapping loads of it's energy just as it is needed to power the glow plugs and supply the 160 - 200amps to the starter.

Wiring from the exciter (as it should be) means that connection is ONLY MADE once the engine is started and the alternator is charging....much better.

Martin

[ewenmaclean]

I am aware of this difference, and you make a good point - my point was that if the large current you are talking before the engine starts is shared between the batteries, as it has been in this case, the current will be taken by the link between the positive terminals mainly, and much less by the current going through the wire connected to the 85/86 pins because of the internal resistance - the currents calculated according to the reciprocal of the resistance.

For that reason I question whether the "trigger" wire is correctly wired up, irrespective of when it is triggered.

[California Dreamin]

My reply wasn't a criticism but to point out regardless of the reasons for melting, the 'trigger' wire for the relay needs re-wiring to the exciter or the split charge relay replacing altogether with a voltage sensing type (which negates the need for this trigger feed).

Who knows what has occured here....when circuits are mixed in this way there are all sorts of senario's that can surface, back feeds through the cut off solenoid who knows..best thing is not to try and make do but take out that which you know is not correct and start again.

Martin

[ninja.turtle007]

Thanks for the replies, very helpful.