Wiring question

[Bogwoppit]

I'm converting a vehicle. I've got a zig, spilt charge relay and leisure battery to put in. I have thin wire which came with the relay to connect it to the starter battery and alternator. Can someone please give me a clue as to what size/amapge/wattage/voltage wire I need to go from the relay to the leisure battery, to the zig, and onwards to power a fridge, lights and a water pump?

I'm stuck and I can't find any info anywhere on the actual size of the cable! Everywhere just says things like - 'You need heavier duty cable for the fridge' etc. But what actual size???

Thankies

[Bogwoppit]

Another stupid question... do I need 2 core cable for the lights and appliances?

And lights - how do the switches fit into the lighting circuit? I'm using separate switches, so need to fit them into the wiring... does that mean each light will have to come individually from the zig unit? Or am I being dense???

[1664]

Have you read these in the Wiki? https://club8090.co.uk/wiki/Ma ... Electrical" onclick="window.open(this.href);return false;

Lights generally have their own individual switches. What Zig is it?

[Bogwoppit]

Hi 1664. Thanks for the reply. I have had a look through the Wiki, but I'm not very good at taking things in... my attention span is that of a goldfish!

It's a Zig Marque 1, which is actually for a caravan, but I'm hoping it will do the job as I will just wire the leisure battery to the 'Caravan' side of the main switch, and not use the 'Car' side at all.

On second inspection the spotlights I've got have actually got their own switches, so I'm thinking they can go all on the same circuit now?

[1664]

It's a Zig Marque 1, which is actually for a caravan, but I'm hoping it will do the job as I will just wire the leisure battery to the 'Caravan' side of the main switch, and not use the 'Car' side at all.

From what I can find, the Zig Marque 1 is identical to the Zig CP400 except that it has an analogue battery voltage indicator as opposed to the green and red LED indicators. It is a distribution unit only and does not have a built in charger. As you say it has a switch to choose between which battery is connected and 3 switches and fuses for the camper circuits eg, lights, water pump, fridge ignition etc. The individual fuses are rated at 10amps I believe giving a potential total power consumption of 30A. I would recommend that you wire BOTH batteries to the unit as
1) your leisure battery system may go pear shaped and you could switch to the starter battery as a temporary emergency supply and
2) you can monitor your starter battery condition whenever you wish.
To safely carry the potential current draw you'll need twin cable sized at 4mm c.s.a to each battery and fused at 30A as close to each battery +ve terminal as possible. Frankly there's no way you'll be consuming that sort of current (it would suck your battery dry in minutes) but technically speaking you could so the wiring system has to be able to cope with it.

On second inspection the spotlights I've got have actually got their own switches, so I'm thinking they can go all on the same circuit now?

What sort of lamps are in these spotlights? If they're filament lamps or domestic type 12v halogen lamps then they're not really suitable for this application due to their high current consumption; the filament type will be about 10 watts and the Halogen can be between 20 to 50 watts. Fluorescent or LED lighting is ideal. I have a spotlight in the back (which takes an old type 10 watt filament lamp) but that was only used for very short durations when I was scratting in the back for something and I have now replaced the filament lamp in it with an LED substitute which takes a fraction of the current.
I'd recommend you wire your lights on at least two separate circuits connected to different fuses at the Zig. That way if a fault occurs on one you won't lose all your lights and be fumbling around in the dark looking for torches etc. Twin 1.5mm c.s.a cable can be used for circuits exiting the Zig; you could use smaller but volt drop is another consideration you need to take into account.

Which brings us to the split charge system (oh dear). Back in the good old days when it were all grass round 'ere and campervans were still in nappies, the 12v equipment consisted of a couple of 8 watt fluorescents,a little used water pump and (if you were 'modern') an electronic fridge ignition circuit. These presented very little load and the leisure battery never really went 'flat' providing the camper was given a run every couple of days or so. Consequently, the split charge wiring and relay were sized to cope with a partially discharged battery rather than a flat one, typically 2.5mm cable and 20A fuses. However, these days there's iPods, Laptops, TV's, hair straighteners, ICE and the like which can pull a battery right down; so down in fact that once the camper is started the leisure battery will suck as much juice as the alternator can give it – way, way more than 20A.
Hence some members on here have been upgrading their systems to cope, the most popular seems to be a 2 pole 'intelligent' relay which monitors the starter battery voltage and switches the relay to charge the leisure only once the starter battery is fully charged. This saves running the 'signal' wire to the relay that's mentioned in the Wiki. The other bonus is that the relay being 2 pole allows you to 'double up' the charging circuit to the leisure battery thus allowing a much heavier current demand without burning out your charging circuit. Size of cable is determined by relay current rating and thus fuse sizes. You need to position fuses at BOTH ends of the charging circuit(s).

There are a couple of old threads in 'Camping' and 'Technical' that go into the detail of this so try searching using 'split charge relay' or similar search terms.

[Bogwoppit]

Thanks very much for all that... I've taken in about half of it so far

A mechanic mate has said today to wire up the 'Car' side of the Zig switch to the starter battery too, which corresponds to your suggestion, yes? So I think I've got the gist of that bit - starter battery straight to 'Car', starter battery and alternator (on separate wires of course) to the relay, then that to the leisure battery, leisure battery to Zig 'Caravan', then 'lights' to lights, 'pump' to water pump, and 'aux' to fridge. Am I ok so far??

Now, you say twin cable... I've just bought 6mm (to be on the ultra safe side and because my fridge is around 8ft from the battery) auto cable, one lot of black and one lot of red. Will that do? Why do I need twin? Is that just to earth stuff? Talking of which, if I'm wiring up the starter battery to the Zig will that have to be earthed?

And if the fridge goes to the Zig does that mean I'll need that one on a bigger fuse than 10 amp or will that do? (Sorry, don't understand the bit about it overall being 30 amp - is each switch not separate then?)

My relay came with some thin (1.5mm? 2mm?) cable. Should I use that or should I use the 6mm for everything? Off hand (it's outside in the bus!) I think it's a 50 amp relay, with two fuses that came with it, I think 30 amp but not sure, I'll look tomorrow. If they are less than that should I change them for 30s?

Lights... they are LED spots, so hopefully won't use much at all. I have six spots and one strip light for the loo I was going to use 2.5mm cable for the lighting, again I've bought one lot of black and one of red. Is that ok? Does each light need earthing separately?

Tbh I won't have a lot of equipment - don't do telly or anything when I'm away, so basically just lights and water pump when standing as fridge will go to gas.

Sorry for all the questions, it's just sooooooooo nice to find someone that will reply!!!

[1664]

no, I haven't forgotten you, but it's nice out & I have a couple of jobs to do on the van before it starts snowing again
I'll reply later today

[jamesc76]

Just one thing about the fridge, I dont know exactly how zig units are set up, but the fridge should be fed from the starter battery side and only able to operate on 12v whilst the engine is running, they use loads of power!

[ermie571]

right folks...treat me gently here....I am no expert.

My zig is the cf8 with charging system, so potentially different to yours with regard to the batteries. Right, I had an issue where the starter would get flat, if switched to charging touring, then parked up.
Mate of mine (ta vwcamperfan) found the following internal wiring diagram for the zig



now...the red circle indicates that the starter is simply added to the circuit, not instead of the leisure, thus linking the batteries. And as with water, leccy I am told likes to be balanced....so the bad will drain the good until they are level. Hence my flat starter (didn't realise I had a leisure that wasn't working properly).

Again, if this isn't the same in your zig, apologies.

Em
xx

[1664]

Emma unlike the Zig CF6/CF8, the Zig CP400/Marque 1 only has a three position single pole switch so it cannot connect both batteries together.

Tracey, what James has said is correct. The only connection between any Zig unit and a fridge is the 12v electronic gas ignition circuit which is only required for the post 'piezoelectric' push button ignition fridge models. It's not because the Zig couldn't handle the current, it's because the battery cannot sustain the 8 to 9 amp demand for any appreciable length of time. The actual 12v fridge supply is only connected via a relay (same set up as the split charge relay) once the engine is running so that the alternator supplies the demand while you drive. Once parked up you are supposed to switch to either gas, or 240v mains operation if you're hooked up on site.

Look what I've just found https://club8090.co.uk/forum/viewtopic.php?p=7366237" onclick="window.open(this.href);return false;

Anyway, you've already bought the 6mm cable – a bit big but that goes in your favour when you use some for the split charge system. I actually only mean twin for the small circuits, not the 4mm but I said twin out of habit

I have made a few assumptions here; that your van is RHD, petrol, starter battery under driver's seat, leisure battery under passenger seat and that your furniture will run down the RHS of your van with the Zig mounted somewhere in or next to it. I am also assuming you will 'double up' on the split charge system as mentioned in my previous post to allow a higher current recharging of the leisure battery.

You need to run 2 x 6mm reds from the leisure battery compartment to the starter battery compartment. Then run 2 x 6mm reds and 1 x 6mm black from the starter battery compartment to the Zig and connect the reds to the Zig selector switch connections by 6mm crimp on 'spade' connectors. As you said, starter to 'Car' and leisure to 'Caravan'. Leave the black for the moment. The battery end of the black either connects straight onto the starter battery negative terminal, or can go on the negative connection to the bodywork itself adjacent to the battery. You then need 2 x 6mm black cables from the leisure battery negative terminal to the bodywork adjacent to the battery in the same way as the one in the starter battery compartment – scrape the paint away to give you the best possible connection (You can re-paint over it after it's connected).
I need to know what sort of relay you prefer using for your split charge (intelligent or standard, rating etc) before I can continue at the battery end. This also applies to the fridge 12v relay.

The 'final circuits' from the Zig (lights, pump etc) should ideally be run in twin 1.5mm or 2.mm cable. Being twin 1.5mm will minimise volt drop and the outer sheath also gives the cable physical strength against knocks and abrasions. Since you have already bought 2.5mm singles you can use them as long as you protect them from rubbing against sharp edges of bodywork etc. Hopefully the size will not prove to be an obstacle when it comes to connection at the light fittings.

If you have an electronic gas igniter on your fridge, simply run a pair (red & black) from the Zig to the fridge igniter connections.
Your fresh water pump wiring depends on how the pump is operated, but I'm going to assume you are going for a remote switch mounted on the furniture or a floor mounted foot operated one. Run a pair from the Zig to the pump via the switch. Connection to the pump should be straightforward. At the switch cut the red cable and connect the red ends to the terminals of the switch allowing the black to continue straight through.
As far as lighting is concerned, you could wire the lights individually back to the Zig but this will leave a lump of bulky spaghetti to wrestle into connectors before final connection to the outgoing Zig terminals, not to mention the amount of cable you'd use. Far better to run two separate circuits (ie, two 'pairs' of cables), 3 spots on one, 3 spots and your fluorescent on the other (your 'strip' light is a fluorescent isn't it?). Just run a pair from the Zig to the first light, a pair to the next light and so on.
The connections to the Zig outgoing terminals are also spade connections which will require crimping. Since you will need 6mm spade crimps for your battery connections to the Zig, it should be possible to 'double up' the 2.5mm cables into one spade crimp should you wish. You have 3 fuses so I would have the water pump on one, 3 spots and fluorescent on another, and 3 spots and fridge igniter 'doubled up' on the other. Frankly, I'd also 'double up' a 12v ciggie lighter type socket with the other 3 spots – if you do get a 12v TV it will have a suitable adaptor and also mobile phone chargers can be obtained with this adaptor. The ciggie lighter on your dash is connected to the starter battery and you wouldn't want to sit for hours in the rain watching TV flattening that at some point in the future.
This leaves you with a clump of blacks which all need connecting to the Zig negative terminal. Easiest way to do this is the just stuff all the cables into one big screw connector.

This just leaves the 12v supply to the fridge. Run a 2.5mm pair from the starter battery compartment to the fridge. Connect the fridge end. By now you must be realising that a lot is going to happen in the starter battery compartment but I need to know your relay(s) decision to carry on.

As an aside, when you run a pair to anywhere, tape the red and black together every few inches or so and support them where needed with clips, cable ties or those sticky back cable supports you can get. Wherever they go through a hole in the metal work, install a rubber grommet to prevent chafing as they will be prone to move when the vehicle is being driven.

[Bogwoppit]

Wow...


1664 Marry me!


That is fantastic information. I am sooooooooo indebted to you!!! Seriously, that is an amazing piece of instruction, thank you so much.

The relay I have at the moment is not a self switching one if that's what you mean by intelligent? It's just an ordinary one, I think it's 50 amps. But if you mean I need a second relay for the fridge then I can get a self switching one if you think that's better? (In other words, have a self switching one for one thing and the ordinary one for the other, whichever way round you think is best). And for not having looked for that forum post myself

I've just been out and bought a crimping tool which will do all sizes, and it strips the cable too Also got some connector blocks to do the lights. I think the cable I've got should be ok for the lights as it can run more or less the whole way along a channel above the windows, but I'll make sure it's well protected. The lights are actually already on one circuit, or were... it was a minibus so had six interior lights in the back. They would come on when you open the door, and also have a switch in the dash. I was going to cut the cable at the door and so isolate the circuit, then connect it from there to the Zig. I've taken the actual lights themselves off, leaving the wires, which I intended to use for my lights. Would you advise against this if you say to put them on two separate circuits? Also - the lights have a piece of wiring coming out of them to connect to which is smaller than the 2.5 I've got. Is that ok?

Good idea about the ciggie lighter! I'll do that for sure.

Not sure if the fridge has an electronic ignition or not... tbh I haven't even looked at it since I took delivery! It's a second hand Electrolux 212A from a caravan. As for the taps - there are two as the caravan had a water heater in, but I will only need to use one. They are proper taps which turn, but only to an 'On' and an 'Off' position, so basically like pressing a switch but turning instead, and there are wires coming out of them... that's the extent of my knowledge!!

Now, I'm going to have to order some more cable if you say not to use that same circuit for the lights, so what size should I get?




Emma, that is very interesting even if it doesn't apply to my zig (I wouldn't know whether it does or not!!! ) It's worth keeping hold of that info just in case. And stop pinching my E

Thanks again so much 1664... If you ever need a rainbow painted on your Dub be sure to ask me!

[1664]

Right then Tracey, as you know I'm in Wales at the moment with Colette, Harry and Phil so having trouble getting internet access (sat outside the local library on their wifi at the moment). Before I went into the relay(s) and fuses side of things that I'd double check that 6mm autocable would carry the same as 6mm 'mains' cable and happened upon this http://www.caravanandmotorhomebooks.com ... g_woes.htm" onclick="window.open(this.href);return false;

Not being an auto electrician and not having ever bought autocable, I was completely unaware of this (frankly ridiculous) shortfall in the description of auto cables which, if correct, would suggest that your 6mm is in fact 6mm c.s.a diameter including the insulation , whereas mains cable being described as 6mm means 6mm c.s.a of copper conductor and does not count the insulation.

I think before you start/continue you need to verify the true c.s.a copper componant of the cables you have purchased - do you know an electrician you can show the cable to? Failing that, pop to your local DIY mega store and look at the size of the copper componant of the equivalent sized mains cables there.

This may just be a storm in a tea cup and maybe your cable sizes are actually what they say they are but best to make sure before you install it all and then find out they're too small. As my internet access is pants at the mo, I'll PM you my phone number.

Oh, and Courgette says we can't get married

[Bogwoppit]

Rotten old Courgette... I don't mind sharing!!

Nah, seriously, thanks mate, I'll have a look at that info about the cable and see if I can get someone to have a look at the stuff I've got before I go any further.

I managed to find some domestic (twin core and earth) cable which I'm thinking I could possibly use for the lighting? Obviously not use the earth wire. It's 1mm though so not sure if that's big enough for my LEDs... If I can use it then I'll be able to do two separate circuits without having to buy loads more stuff

Hopefully the bloke is coming to do the welding sometime this week and he knows about leccy as well so he can tell me what I've done wrong so far!

[nedkelly113]

Hi
I wouldn't use domestic cable in your van it'll get too hot if its close to its max rating. You need tri-rated cable. The cores are much thinner and there are more of them so the current carrying capacity is higher for same size cable. And its much easier to work with. Pop into halfords and have a look at thier cable. Bit pricey but it'll show you the diameter you'll need for your various circuits.

Ned

[1664]

Tracy, there's no reason you can't use the lighting wiring that is already installed in the van and connect it to the Zig – you're using exactly the same lights that were connected to it in the first place aren't you? There is no reason to split the existing lighting circuit into two circuits other than in the unlikely event of a fault blowing a fuse, you would have another healthy circuit running a few lights just to get you by until the fault was fixed. You don't have to split it up.

I wouldn't use domestic twin and earth cable for the lighting or the fridge either. The copper cores are solid rather than stranded and so do not cope very well with repetitive movement or vibration which is inevitable in a vehicle. If your original cables do not fit the bill, buy some 2 core flex or twin cable with stranded cores http://cgi.ebay.co.uk/10M-FLEXIBLE-2-CO ... 3cab976a38" onclick="window.open(this.href);return false;

You will struggle to source a 2 core 2mm/2.5mm size so I'm tempted to say use the 1.5mm for the lighting (if needed) and the fridge. The cable is also rated high enough to easily cope with the current demand of the fridge (9amps approx) but as you said your fridge is some distance away I'm a bit concerned about the volt drop. I'd still be tempted to temporarily wire the fridge up with it and try it out. Failing that by far the cheapest solution is to buy some 3 core 2.5mm flex which is widely available and simply cut the earth off at both ends.

In an ideal world, this is the stuff for the job http://stores.ebay.co.uk/Kojaycat-Vehic ... ec0Q2em322" onclick="window.open(this.href);return false;
but the prices are frightening and frankly the cable in the first link will do the job perfectly adequately.

You do need to ascertain the true size of the “6mm” cable you bought though.

I shall mention the 'sharing' option to Courgette but don't get your hopes up. Besides, I'm no spring chicken......

Hi
I wouldn't use domestic cable in your van it'll get too hot if its close to its max rating. You need tri-rated cable. The cores are much thinner and there are more of them so the current carrying capacity is higher for same size cable. And its much easier to work with. Pop into halfords and have a look at thier cable. Bit pricey but it'll show you the diameter you'll need for your various circuits.

Ned

Ned, there's no need for tri-rated cables. The mains cables ratings are calculated to ensure they don't get too hot (too hot being greater than the melting point of the insulation which in the case of PVC is 70C). Tri-rated insulation can withstand greater temperatures which is why the copper cores can be smaller for any expected current flow. You are also forgetting that smaller cores mean larger volt drop over a given distance. The current demand of Tracey's circuits a way below the rating of the cable and I doubt they'd even get warm let alone 'hot'; the larger size is just to try and alleviate any volt drop that might occur as her potential loads are quite spread out from the sound of it.