LDV Convoy Minibus. Question about Jump Starting (Dual Batteries). Any experts?

Hammyman

It was 12V so it doesn't matter a toss which one it was connected to.

vaio

gilbert_and_sullivan wrote: »

You'll never get agreement about jump lead connections, in car strorage compounds where they jump start dozens of vehicles every day, the mini buses used by the ferry drivers have permanently connected jump leads with the crocodile clips attached to a rubber wrapped bar when not in use.

One of the ferry drivers will simply touch the contacts to any of the battery terminals if the flat vehicle is 12v and a mate will start the flat car, no finesse, no worries about sparks or shorts or spiking, simply get on with it no time for mucking about.

What i'm interested in knowing here was this LDV van completely flat, if so did the one set of leads start it?...in my experience it usually takes 2 or sometimes 3 sets of good quality leads to jump start vehicles of this type, 12v vans and 4x4's, if they are completely drained, where a 24V 14 litre truck will happily fire up with one set, most odd.

From the way I read they OP, they didn’t jump start it in the tradition sense, they left the leads connected for 25 mins which effectively recharged the flat battery which then started the van.

gilbert_and_sullivan

vaio wrote: »

From the way I read they OP, they didn’t jump start it in the tradition sense, they left the leads connected for 25 mins which effectively recharged the flat battery which then started the van.

Ah would appear so, i'm much obliged to me learned friend.

Rover_Driver

gilbert_and_sullivan wrote: »

What i'm interested in knowing here was this LDV van completely flat, if so did the one set of leads start it?...in my experience it usually takes 2 or sometimes 3 sets of good quality leads to jump start vehicles of this type, 12v vans and 4x4's, if they are completely drained, where a 24V 14 litre truck will happily fire up with one set, most odd.

If a 12v vehicle takes, for example, a 100 amp supply to start, if it was a 24v vehicle it would only take 50 amps, (double the voltage, halve the current) and it is the size of the conductors in the jump leads and the current flow in them that is important.

gilbert_and_sullivan

Rover_Driver wrote: »

If a 12v vehicle takes, for example, a 100 amp supply to start, if it was a 24v vehicle it would only take 50 amps, (double the voltage, halve the current) and it is the size of the conductors in the jump leads and the current flow in them that is important.

Still doesn't explain why a 2.5 litre Transit or almost any old school Japanese 2.5 to 3 litre Diesel 4x4 needs three sets when a 12/14 litre 6 pot truck engine will happily jump from one set.
The differences in compression pressures should more than take out the voltage difference.