What's going on?

[Vagophile]

I used my Cali as an office all day on Thursday and last call was our local supermarket quite near home. It's a 2013 two litre bi-turbo blue motion stop/start model. After the shopping, the van refused to start, exhibiting all the signs of a flat battery. No problem, I'll just walk home and return with my car complete with jump starter and jump leads. When I got back, I checked the Cali battery voltage at 11.8 volts. Surprise. After connecting the jump starter (9000mAh lithium-ion polymer fully charged), the engine would hardly turn over, definitely no chance of it starting. The same happened when I used the jump leads. Both the jump starter and jump leads have been used in the past to start both diesel and petrol engines up to three litres without any problems. I removed the battery, took it home, charged it overnight and fitted it the next day when it was showing 12.8 volts. The van started immediately, even though the temperature was minus two degrees centigrade.
Is there something in the stop/start electronics that has prevented the booster process from working successfully?

 

[WelshGas]

I used my Cali as an office all day on Thursday and last call was our local supermarket quite near home. It's a 2013 two litre bi-turbo blue motion stop/start model. After the shopping, the van refused to start, exhibiting all the signs of a flat battery. No problem, I'll just walk home and return with my car complete with jump starter and jump leads. When I got back, I checked the Cali battery voltage at 11.8 volts. Surprise. After connecting the jump starter (9000mAh lithium-ion polymer fully charged), the engine would hardly turn over, definitely no chance of it starting. The same happened when I used the jump leads. Both the jump starter and jump leads have been used in the past to start both diesel and petrol engines up to three litres without any problems. I removed the battery, took it home, charged it overnight and fitted it the next day when it was showing 12.8 volts. The van started immediately, even though the temperature was minus two degrees centigrade.
Is there something in the stop/start electronics that has prevented the booster process from working successfully?

Maybe a poor connection that was fixed by removing then re-installing the battery?
Where did you connect the black -tve connection of the jump leads or power pack?

 

[Vagophile]

Where did you connect the black -tve connection of the jump leads or power pack?

To a bolt head at the bottom of the partition on the left of the battery compartment. On reflection, maybe not a very good connection, but the jumper leads are quite short. If there's no trick to jump starting a stop/start engine, then I'll have to accept operator error. Where is the recommended earth connection when jump starting?

 

[WelshGas]

To a bolt head at the bottom of the partition on the left of the battery compartment. On reflection, maybe not a very good connection, but the jumper leads are quite short. If there's no trick to jump starting a stop/start engine, then I'll have to accept operator error. Where is the recommended earth connection when jump starting?

That’s fine. Since everything was resolved after removing, charging and then refitting the engine battery I believe a poor connection on the battery +/- pole was the problem. Resolved by redoing the battery connections.