Jump starting a VW van

AdrianC

ElephantBoy57 said:

I do have a cigarette socket multimeter to monitor the voltage, but not sure it will be of any use. From the cigarette socket, the voltage reading seems lower, around 11.5v, 13.9v when engine running, started ok.

That's telling you what you want to know.

11.5v is pancake.


13.9v is low for charging voltage - it should be nearer 14.5v. It may be being dragged down by a very flat battery, though.
If it stays that low, then your alternator's not putting out as much as it should be - and that'll be a part of why your battery discharged.

ElephantBoy57

AdrianC said:

11.5v is pancake.  13.9v is low for charging voltage - it should be nearer 14.5v. It may be being dragged down by a very flat battery, though.
If it stays that low, then your alternator's not putting out as much as it should be - and that'll be a part of why your battery discharged.

I think its a low reading because its a cheap USB reader and not a proper multimeter taking a reading at the battery. Increase both readings by 1v and its looking normal.

11.5v and it started perfectly ok. When I get the chance, I will take a reading from the battery with my multimeter.