Club 80-90 Forums

Jumper cable may well be good enough (depends how thick) and I'm fairly sure cooker cable is thick enough too - just a thought. You can buy big terminals in some accessory shops and certainly available online. Solder and crimp tight.

http://cgi.ebay.co.uk/600amp-7-8Ft-Long ... 518cc2d1f3" onclick="window.open(this.href);return false; - cheap

I reccomend crimping them. Quicker, easier, safer and costs less also less likely to mess the job up. If you have been at sea fishing since you were five OBG isnt it time you had a rest? A lot of these jumper cables are only rated for short and ocassional use, not suitable for long term continous use such as battery charging. Quality cable is expensive. I cry every time I have to buy some. However my projects work, they stay working and more importantly no one gets hurt. Oh and sometimes the punters pay me as well. LOL.

Cafnod wrote:I reccomend crimping them. Quicker, easier, safer and costs less also less likely to mess the job up. If you have been at sea fishing since you were five OBG isnt it time you had a rest? A lot of these jumper cables are only rated for short and ocassional use, not suitable for long term. Quality cable is expensive. I cry every time I have to buy some. However my projects work, they stay working and more importantly no one gets hurt. Oh and sometimes the punters pay me as well. LOL.

Cooker cable is not suitable. It is solid core and not suitable for use in vehicles/boats/planes etc as the vibration can cause it to fracture.

I'll rest when I am dead!Old fishermen never die - they just smell that way!
I've been spoilt when I've got hold of jump leads - I've always managed to find cheap top-knotch flexible ones.
You work and get paid? What is this country coming to?

I like your guys enthusiasm even if I don't totally agree with the context of your comments.
I know I am on a hiding to knowhere with this one but I do think some of your recommendations are a bit over the top and whilst I would totally agree with the principle of bigger is better you can only call these comments a recommendation based on your opinions. However, reading your replies it does sound like you are implying that 100amp cabling and 140amp relays are necessary and not just a personal recommendation.
My point.....on a two battery setup: One 72 amp starter battery and one 100amp leisure... even with a flat leisure battery, the alternator regulator is controlling rotor magnetic strength based on the state of overall battery voltage. As both leisure and starter batteries are linked the regulator believes it is charging one partially charged battery and alters the rotor magnetic strength (alternator output) accordingly. What this means in real terms is the infinitely variable output of the alternator very rarely hits it's maximum output and when it does much of this current goes directly to anchillaries such as lights/heated rear window and blower motors. Besides, full alternater output is only likely to happen if both batteries are flat and obviously the split charge circuit is there to prevent this happening anyway.
I just don't believe such heavy wiring is required although no harm is done is has no obvious benefit.
Let me use VW and Westfalia's own factory split charge circuitry as an example: A California/Atlantic has a 40 amp relay with 30amp fuse. Occasionally owners complain that with a totally flat leisure battery the fuse will blow. By this you can deduce that on initial start this circuit has a peak amp draw to the leisure exceeding 30amps! but only for a few seconds, after which time the amp draw drops sharply to below 20amps (I know, I've used an expensive amp clamp meter to test my own setup under these exact conditions)
Now lets get back to 140amp relays and 100amp cabling....a necessity or an opinion.....people will make there own minds up.
Having said all of this, I think the standard Westy split charge circuitry is adequate at best and could be improved upon but my recommendations for upgrading would be based on the known requirements of a modest two battery split charge system and they would be:
70amp relay (large terminals on the switched connections)
50/60amp cabling on the switched wiring 16 amp cabling on the switching side.
40/50amp fuse
That's essentially doubling up on the known demand of an average flat leisure/partially charged starter split charge system.
Things would obviously be different for a multi leisure battery setup but that is discussion for another time.
Cafnod
Your picture example may have been 100% reliable for four years but those small relays and buzz bars look worryingly close to eachother. If those relays come loose on their screws they could swing and touch, the same goes for the two large poss and neg cables on the buzz bars although I amit this would be unlikely, for me they are just too closely mounted.
No offence intended, just my opinion.
Martin

There are a couple of benefits.
If the starter battery is fully charged and the leisure discharged think about the current that will suddenly flow upon starting the engine - alternator plus charge from the starter battery, this will be in the order of 100A not 40A. You are not just dealing with the output from the alternator.

The heavier the cable the better to negate voltage drop, if you are charging a 110Ah leisure battery you need all the volts you can get from the system to keep it in good order.(I use a 40w solar panel also to keep the leisure in peak condition - another can of worms)

For the sake of a few pounds it is well worth putting in an efficient system. (Most of you would doubtlessly spend the same amount of money on aluminium tubes containing a brown liquor without thinking about it!)
These recommendations are from tried and tested systems that have been carefully researched. (see SBMCC.co.uk - self build motor caravanners club)
Quoting a 25 year old VW policy of fitting a system that was adequate at the time is ridiculous - we are making greater demands on the electrics today so fit the best not something that is just adequate or a small step up. I have yet to hear of anyone that has regretted setting up a good system but there are several that have rued putting in an underrated system.

Cafnod doesn't get many potholes/ lurching on his narrowboat!(quite a smooth ride on canals).

OBG...you are quoting lots of figures...where do they come from? if you are saying 100amps is flowing to the leisure on start (with a flat leisure)why is it that so many westfalia owners have never blown their 30amp fuses? have they never had a flat leisure battery?
You say that quoting 25 year old policies is ridiculous because we are making greater demands nowadays....when most of these vans remain pretty standard and untouched and the basic alternators and leisure batteries remain rated pretty much as they were coming out the factory. Sure some owners have extra lighting and Audio but this is usually used parked up 'on camp' and simply flattens their battery quicker.
As for my recommendations being a 'small step up' I don't call a 70% increase in relay size and around a 50% increase in cabling size a small step.
I am not arguing against over rating a system....there is never any harm done by using heavier gauge wire or larger relays, my point is, you shouldn't be misleading owners by suggesting anything less is inadequate when clearly this isn't the case.
Martin

right guys cant seem to find any push fit terminals that will take 10mm cable, how do i go about getting the thick cables to attach to the relay, the biggest push fit i can find is to take 6mm, i want these http://cgi.ebay.co.uk/10-YELLOW-CRIMP-T ... 25576f04eb but need em to take the 10mm cable. also where do i find put an inline fuse to put into the 10mm cable ?

wat do i buy guys, links would be useful ? ive found the inline fuse before the relay was melting away nicely too so for now ive took the wires out but wanna get em replaced asap as me stereo/lights are on the 2nd battery and this wont be recharging as it is.

thanks again

Well I'll just bite my lip.......
Now you have gone for 10mm cable it kind of makes your choices rather limited.
This kind of relay will be your best choice as it has stud terminals so you can fit larger eyelet terminals

http://cgi.ebay.co.uk/Heavy-Duty-Relay- ... 3001r34037" onclick="window.open(this.href);return false;

These type of eyelet connections:

http://cgi.ebay.co.uk/Battery-starter-c ... %26ps%3D63" onclick="window.open(this.href);return false;

This should be up to it (60amps fuse holder) not as heavy as your main wiring tho..

http://cgi.ebay.co.uk/MAXI-FUSE-HOLDER- ... 3357272ceb" onclick="window.open(this.href);return false;

Martin

ok thanks for that, but as ive now gotta basically start again wat would you suggest, i dont by any means have to use 10mm cable, i could go for thicker if needs be ? i just wanna install wat would be the most reliable/best so watever you guys suggest i shall do.

thanks

Hi Hixsy
Been out doing the fireplace on my boat today. The tiling was an absolute pig, but we neednt go there.
A bigger relay to take heavier cables should have stud terminals not push on types. Ring terminals of whatever size I can crimp up for you or you can just pop into a friendly auto electricians and they will probably do it for free. get some heatshrink to seal the join of the terminal with the wire.
Reason I am suggesting heavy cable is as OBG says voltage drop. The higher the current the greater the voltage drop. also if its running underrated it doesnt get hot and melt insulation and diesnt melt fuses either. Clamp meters. Probably a snapon. Personally I use fluke gear, I have snapon still but rarely use it. Thats another discussion though. Tolerance on relays current handling can be up to 20%. Therefore we are looking at a lesser increase than 70% when we take such a large variable into consideration.
where do I get my figures? The BMEA, the IEE and the word of a good friend who teaches electrical engineering and who used to design and install the wiring for operating theatres among other things. Oh and another friend who designs a lot of the control gear for modern cars. I can ask for sources to be cited if necessary.
Vehicle wiring products a good, but a little on the dear side.
Designers of anything are unable to future proof there systems. Nor are designers infalable, please do not forget they may also be constrained by the number crunchers there brief may be about cost rather than efficacy. And as OBG says a thirty year old system. A lot of the stuff we use did not even exist then.

ok thx mate for the info, if im honest i just dont get this electrical jargon lol

would you link us the bits i need please ? wat size wire ya suggest etc ? also is the negative/ground as important, will i need as thick cable for that too?

Hi Hixsy
Its confusing but stay with it and you will be helping other people soon mate, we all had to learn and not all minds deal with knowledge in the same way, for example I loathe bodywork.
Relay as suggested by RW would be fine. 10mm cable ample. yeah you need the earth to be the same size but only a short earth as it will bolt to the body, not return back to the starter battery. In marine electrics everything has to be earthed individually thats why when you saw my wiring there were a lot of wires, everythings is earthed back to the batteries, directly or to earthing points then by a cable the same size as the positive feed cable. But all thats another issue soz.
If you can buy all your gear from one place and tell them you want the terminals to suit the cable and the relay. If seperate get the stud diameter of the relay power terminals and ask for ring terminals to suit the cable and the stud diameter. its pretty easy, also there are only a few sizes. Its a bit like buying a pair of jeans, you need two measurements. You can get a maxi type fuse holder, or you can buy a strip type fuseholder, here is a good place
http://www.vehicle-wiring-products.eu/V ... mepage.php" onclick="window.open(this.href);return false;
Not the cheapest but very comprehensive and they will help you out over the phone by checking terminal sizes and stuff for you and although they have p & p standard rates they have helped me out by charging a couple of quid if I need the odd bit. I have dealt with them for years.

ok ive ordered this http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... K:MEWNX:ITand the relevant amp cables etc, so touch wood i should be fine when i get it installed

bit annoyed that i followed wiki stuff

use 35 amp fuses and 35 amp wires instead

and it still werent enuff for my setup. Has every1 else whos used them instruction been ok ? Maybe it needs to be updated telling people they'll be needing 100amp+ wiring/relays? or maybe im just unlucky..lol

40amp relays should be fine. Are you drawing a lot of current generally Hixsy?