Voltage drops across the entire system

[WLC]

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So, the relay remains, to keep the circuits isolated when the engine is not running.

Say you run a thick cable direct from alternator to leisure battery, and leave everything else as it it John.

Does your splitter still keep the circuits isolated when the engine is not running please

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[ghost123uk]

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So, the relay remains, to keep the circuits isolated when the engine is not running.

Say you run a thick cable direct from alternator to leisure battery, and leave everything else as it it John.

Does your splitter still keep the circuits isolated when the engine is not running please

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No, that would not work because where the new cable connects to the alternator there is also the existing cable, which goes to the main battery +ve, so you would be making a permanent connection to both batteries +ve terminals.The splitter (relay) has to be there to prevent this.

[WLC]

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No, that would not work because where the new cable connects to the alternator there is also the existing cable, which goes to the main battery +ve, so you would be making a permanent connection to both batteries +ve terminals.The splitter (relay) has to be there to prevent this.[/color]

Not a problem John

Simply remove the existing power cable at the alternator and insulate it's end
Best to secure the loose end somewhere so it can't make contact with an earth.

Now mainline electricity along a thick cable direct from your alternator to your leisure battery
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[Oldiebut goodie]

Is this for real?

[WLC]

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Is this for real?

You bet Pop

It's a no brainer.

You've got two batteries, one is nearly full, one is nearly empty.

Which one do you mainline electricity to

Like I said, it's a no brainer.
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[Oldiebut goodie]

I am beginning to wonder who is the no brainer !
You intend to disconnect the starter battery from the circuit - you will end up with a dead van.
I'm out of this - it is getting a bit silly now.

[WLC]

I am beginning to wonder who is the no brainer !
You intend to disconnect the starter battery from the circuit - you will end up with a dead van.
I'm out of this - it is getting a bit silly now.

No way Jose

You've got two batteries, one is nearly full, one is nearly empty.

Which one do you send electricity to via a relay that only drops voltages when the current is high

Like I said, it's a no brainer.
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[Oldiebut goodie]

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Simply remove the existing power cable at the alternator and insulate it's end
Best to secure the loose end somewhere so it can't make contact with an earth.

Now mainline electricity along a thick cable direct from your alternator to your leisure battery
.

As I said this is getting silly, I'm out of here.

[WLC]

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Simply remove the existing power cable at the alternator and insulate it's end
Best to secure the loose end somewhere so it can't make contact with an earth.

Now mainline electricity along a thick cable direct from your alternator to your leisure battery
.

As I said this is getting silly, I'm out of here.

As you wish
But you could be missing out on the best thing since sliced bread
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[Mocki]

How about just replace the main wire from the alternator to the starter which has most likely gone high resistance ?

[WLC]

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How about just replace the main wire from the alternator to the starter which has most likely gone high resistance ?

That's pretty deep water Sir.
I'll PM you either today or tomorrow
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[Mocki]

Nope, no deep water, just plenty of years experience fault finding on these vans.....
Simply replacing the output feed from the alternator that goes 20" to the main terminal on the starter with a better quality ( double the thickness) replacement could solve johns problem...

Moving the main battery to the engine bay and using the now redundant main battery feed to feed the fusebox and the split charge next to the leisure battery also is a easy mod that improves things.

[WLC]

Nope, no deep water, just plenty of years experience fault finding on these vans.....
Simply replacing the output feed from the alternator that goes 20" to the main terminal on the starter with a better quality ( double the thickness) replacement could solve johns problem...

Moving the main battery to the engine bay and using the now redundant main battery feed to feed the fusebox and the split charge next to the leisure battery also is a easy mod that improves things.

Have you tried mainlining electricity down a thick cable straight into the leisure battery
If so, what was the voltage drop between alternator and battery live please

Yeah, using the redundant starter cable and a thicker cable between the alternator and the starter solenoid will improve things
PM coming your way

[itchyfeet]

Ghost back to your OP,

I wonder how long you let the van idle for before you took these measurements?
What was the state of charge,
how much do you use it?
When did you last charge or trickle charge the battery?

I don't need to tell you that If there is any significant charging current the resistance of the wires will give volt drop.

I just did the same test but I have had my van on charge overnight because I haven't used in for 2 weeks, the charger soon went to trickle charge after a couple of hours so the battery levels are good.

Immediately after start up and after the split charge relay connected I saw about 13.1V on the leisure batt voltmeter but it soon climbed after a few minutes to the figures below presumably because it was well charged so the current flow soon dropped off.

I suspect my drop from alt to batts is mainly due to ignition current, as I rev this voltage drops a little as the coil draws more current.

I'm going to do this again after the van has been standing unused for a week or so and see how it compares.

I should add the regulator is also 14.5V and new, fitted by the company who did the bearings so it may be a cheap and nasty one as its reading low, any reccomendations for better quality 14.5v regulators greatfully recieved

[WLC]

I'm going to do this again after the van has been standing unused for a week or so and see how it compares.

.
If you turn the headlights on after after your voltage reading at starter has settled down you will a rough idea of voltage drop against a rough idea of the extra current flowing
A side / rear bulb takes about 1/2 amp, a headlight takes about 5 amp.
Unless you run special bulbs of course

It's bit trickier putting a known load on your leisure battery I'm afraid

It's not very scientific of course, but it does give a picture of what's going on
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