Help get us home from the Alps! (Auto Electrics)

[Citizenfish]

We are currently in the Alps in our motorhome, how we made it I don't know. I'm not sure we're going to make it back unless someone can help solve this total mystery.

 

Van is a coachbuilt on a Fiat 2.3 diesel, 2008 (Ci conversion)

 

Our charging system is failing but appears to be failing randomly. We drove from swindon to Dover fine and stopped the van waiting for the ferry. Then I started it to drive on and got the battery warning light. I thought this was odd but ignored it. Driving off the ferry warning light again. We stopped in a layby and I measured voltage over the battery, 12.4 volts. Not good as it should be 14v with the alternator going.

 

I stopped then started the van and the voltage went up to 14v. So we decided to keep going.

 

We then drove 200 miles and stopped for diesel. Starting the van, warning light comes on again. No amount of fiddling or fuse pulling can get it to go away. Our only choice was to gamble, so we drove another 120 miles until the battery was near flat (I have a spare) and camped for the night.

 

Next morning, the van just about manages to start on the old battery, and guess what 14v at the battery. We drive 300km and stop for diesel. Start again and the warning light is back on.

 

The only link I can make is a warm engine is causing it and there is some sort of relay/cut-out circuit that is killing the charging current to the battery. There must be a split charging circuit as the leisure battery charges when we are moving.

 

We notice that if we put the fridge to DC charge, the light stays lit for ten seconds after starting then it switches off completely after we hear a relay click.

 

I have 4 days to fix this before we head home. I'm pretty certain the alternator is ok (when it works) as it is brand new (replaced in Feb).

 

What else should I check? I cannot find the schematics for the van online and don't have them with us. Any other ideas most greatly appreciated.

[BGD]

I've had this symptom on a couple of vehicles over the years.

 

First and really simplest check is to ensure cable connections on battery terminals are REALLY clean and really TIGHT.

Wiggle the clamp connections hard. Any movement at all, and they are too loose.

Ideally, remove the clamps from the terminals, clean, sand the contacts and clamps, and re-attach. (Make sure you've got any radio codes etc to hand in case you need to re-enter them after disconnecting/reconnecting engine battery.

 

In a roadside emergency, you can even tap the top of the clamp connectors lightly with a small hammer etc (watch you don't short the live connection to anything metal near the battery!) to ease them a smidge further down & tighter onto the battery terminals.

 

This was the cause of the intermittent battery-light-on problem both times for me.

 

Good luck.