What cable type for -ve earth?

[dsmith1974]

I would solder the ends.

Martin

So would I

Guess I'd better do that too, they're just crimped at the moment. Will it need a specific kind of solder or tip or will any do?

Thanks
Duncan

[CovKid]

I always use a gas soldering iron as you need substantially more heat than the average 20w iron. However, I picked up a big 100w iron from Maplins at the weekend. Seemed a good deal at £15. I used cored solder but guess you could even use plumbers and flux - don't see why not. There aren't that many jobs on a T25 where a big iron is needed (starter brushes?) but its still a good thing to have. Shrink tubing worthwhile too. Neatens and seals the job.

[ScienceBoy]

I always use a gas soldering iron

I need one

[ghost123uk]

they're just crimped at the moment

Soldered properly is good, but well crimped is OK too, it's what VW did. Soldering "big stuff" like this requires a bit of practice/experimenting/experience, but it is a good and fairly simple skill to learn. Personally, I find flux and non"multi-core" solder is the way to go on "big stuff" and if buying solder from the likes of Maplin, don't under estimate how much you will need

[CovKid]

Aye, Maplins not being the best place in terms of cost.

The big advantage with soldering is its ability to 'seal' the connection somewhat rather than leaving exposed copper which soon tarnishes. In conjunction with shrink sleeving, you get a solid air/water-tight seal. Trick is to avoid wicking otherwise it'll flow further down the cable than you might think causing it to be too stiff in some applications. Practice is the key - that and monitoring how much solder is being absorbed.

Certainly (for me) anything exterior gets soldered and sealed. I actually did the same with the mega dash cable and junction boxes I put in the WIKI. Mostly because once done, I didn't want to have to revisit the job. I still have to be REALLY careful where I use main beam - it is ridiculously bright.

VW crimp loads of cables but the earth crown is a notoriously weak point and I always felt that should be more substantial.

Like all manufacturers, VW fitted what would meet needs at the time (at minimum cost and only marginal headroom) but for most of us we've added more electrical items and those thresholds are soon exceeded. The earth should at least match the positive.

This page covers ideal cabling: https://club8090.co.uk/wiki/VW ... headlights" onclick="window.open(this.href);return false;

[dsmith1974]

Thanks all. I can have a practice with a gas iron, core solder and heat shrinks at the weekend (see how close I can get to CovKid's picture above..) But it's good to know that a strong crimp should suffice for inside (takes the immediate pressure off..)

On a plus note, I did manage to get the alternator charging both batteries and all ancillary leisure components (lights, stereo etc,) working by replacing the VSR and re-connecting some loose wires (hopefully in the right places!).

I made a circuit diagram of the existing setup, but am not sure I understand it 100%. Will try and upload it tonight. It would be good to know if it looks safe or not.

[dsmith1974]

Apologies for the overlap with often recurring threads, but would anyone mind advising on whether the circuit below looks safe/usual or unusual, please? Everything's now working, but there are a couple of areas I don't fully understand yet, and it'd be nice to have some peace of mind that the batteries won't be exploding anytime soon..



Usage
On Arrival
* (Optionally) Unscrew ISO (to prevent any possibility of LB draining VB).
* Flick the CXP7 switch from OFF to LEI (Caravan Battery).

Before Leaving
* Replace ISO.
* Switch CXP7 from LEI to OFF.

What's understood
* When CXP7 is switched to LEI it joins the lead from LB+ with STB.E (and in turn bridges STB.A and STB.C (providing power to the interior lights, Propex heater and water pump)).

* The LB receives a charge from VB+ via STB2.B/VSR.O/P(A)/STB1.B (so long as the alternator is running).

* LB always powers a 12v DC power outlet that can be used to power a TV/DVD player.

* LB always powers the radio via STB2.D.

What's not so well understood
* Shouldn't CPX7.1 (CAR) be connected directly to VB+?

* If I disconnect VSR.Pwr In 2 then the measured voltage at the battery posts drops from ~13.6v to ~12.6v..
..it's as if the alternator output is returned through the chassis GND and is routed through CPX7.1 (CAR) into VSR.Pwr In 2.

* Disconnecting VSR.O/P(B) makes no difference to anything as far I can tell.

* From the manual I got the impression that VSR.Pwr In 1 switched to OP(A) and Pwr In 2 switched to O/P(B) independently but in practice an increased voltage in Pwr In 2 also results in an increased voltage to O/P(A)

http://www.rydertowing.co.uk/downloads/ ... 1170-3.pdf
http://www.freewebs.com/12voltsdc/Zig%20CPX7.pdf

Many thanks,
Duncan

[dsmith1974]

I always use a gas soldering iron as you need substantially more heat than the average 20w iron. However, I picked up a big 100w iron from Maplins at the weekend. Seemed a good deal at £15. I used cored solder but guess you could even use plumbers and flux - don't see why not. There aren't that many jobs on a T25 where a big iron is needed (starter brushes?) but its still a good thing to have. Shrink tubing worthwhile too. Neatens and seals the job.

Crimped, gas soldered and heat shrinked today. Looks and feels much better. Ta.