:( Hi all, Can anybody see any problems if I pick up a 12v pos permanent and a 12v pos ignition switched, in the fuse box next to the drivers door, Is it OK to insert some contacts into some unused fuse positions which are correct on the live side of the fuse box. Its to feed the electrics for a caravan so it would power the fridge with the engine running (8amp) and charge the van battery and be able to power the caravan off the car in an emergency (8amp) the caravan has change over relays so the max current would be in the region of 10amp off the permanent fuse.Would it upset the CAN bus ? cheers - Stuart.

:( Hi all, Can anybody see any problems if I pick up a 12v pos permanent and a 12v pos ignition switched, in the fuse box next to the drivers door, Is it OK to insert some contacts into some unused fuse positions which are correct on the live side of the fuse box. Its to feed the electrics for a caravan so it would power the fridge with the engine running (8amp) and charge the van battery and be able to power the caravan off the car in an emergency (8amp) the caravan has change over relays so the max current would be in the region of 10amp off the permanent fuse.Would it upset the CAN bus ? cheers - Stuart.

Hi Stuart

I don't know where you are getting your figures from ?

You are looking at at least 30 Amps to supply every thing, but the easiest way to connect all what you want and not have any problem with can-bus,

is to drop a wire straight from the battery (protected by a fuse) down along the chassis and up into the boot, and connect a "Smartcom"

http://www.towsure.com/product/1828-Self-Switching_Combination_Relay

and then from there take the the three outputs 1, the fridge 2,battery charge, and 3, permanent live, the first two will become live when the engine is

running and go off when you turn off the engine.

My main advice is when wiring from the battery use as thick a cable as you can, because if it is too thin you will loose a large voltage drop at the caravan

You can loose as much as 3 to 4 volts and at 30 amps that will not be enough to charge the battery or run the fridge, I would suggest at least 10mm

cable but the bigger the better.

Radiotwo

Hi radio2 (name ?) Don't think it will be anything like 30a ! the fridge will pull 8a when the engine is running and as for charging the battery I did a test once with a flat (10v) batt and I was putting about 2a into it and that was at the 7 pin socket at the back of the car,and it was wired in 6mm cable ! you are correct in wiring it in a large cable as people think because its only 12v that they can use a 1mm cable with the corresponding voltage drop. Our caravan is a 2005 with the switch over relays built in the fuse/control box and it only needs a permanent feed and a switched ignition and it will switch the fridge in circuit and also has a relay for the battery charge. I have already run the cables to the fuse box so its just a matter of inserting some fuse connectors in the correct places as the wires to the fuse box are fairly large, I just don't know if any of the input circuits are CAN bus controlled (circuit diagram ?) can any of the dealership lads help out ? thanks for the reply radio2, what caravan have you got ?and what do you tow it with ? cheers - Stuart.

Hi radio2 (name ?) Don't think it will be anything like 30a ! the fridge will pull 8a when the engine is running and as for charging the battery I did a test once with a flat (10v) batt and I was putting about 2a into it and that was at the 7 pin socket at the back of the car,and it was wired in 6mm cable ! you are correct in wiring it in a large cable as people think because its only 12v that they can use a 1mm cable with the corresponding voltage drop. Our caravan is a 2005 with the switch over relays built in the fuse/control box and it only needs a permanent feed and a switched ignition and it will switch the fridge in circuit and also has a relay for the battery charge. I have already run the cables to the fuse box so its just a matter of inserting some fuse connectors in the correct places as the wires to the fuse box are fairly large, I just don't know if any of the input circuits are CAN bus controlled (circuit diagram ?) can any of the dealership lads help out ? thanks for the reply radio2, what caravan have you got ?and what do you tow it with ? cheers - Stuart.

Hi Stuart

(Name?) you mean to say that is not a big enough clue !!

Again I think you need to do some more tests, as the new fridges are rated between 10 to 20 amps on some of the bigger fridges, and as for battery charging, thats another reason for thick cable, if you say

it was only drawing 2A @ 10 Volts then there was a problem, either a very high resistance or very thin cable, or the battery was duff.

I know the caravan has built in relays, but I still like to have some sort of isolation especially for the battery connection as if the car battery was flat, and you try and start it, the current would come from the

caravan battery, which would burn it out !

You say you have wired to the fuse box but I bet it is not very thick cable you have used ? and even then running down to the back of the car it would be too thin.

You ask what caravan, mine is a Bailey Champagne 2005, and tow with a Toyota Amazon,

But as said I would not touch the cars fuse box but , use one length of cable down to the back of the car, I know this is a bit over the top, but I use 50mm cable from the battery to the boot, and tap off for the

smartcom and I get 14.5 volts at the caravan battery and full voltage at the fridge and get ice in the freezer box within 1 hrs drive, now as I said over the top, but I also have a socket for a anderson plug to run

a winch.

Steve

I recently took a feed for my towbar electrics (only basic single electrics) from a bus bar at the rear of the fuse box - the fuse box is designed for distributing a heavy load, so I would have though you would be fine assuming that you choose your cable sizes and fuses correctly. Ideally you would add new fuse connections to the fuse box but I don't know how easy it is to get the necessary connectors, in my case I took a feed from the bus bar at the rear of the fuse box which has spade connectors on it.

The instructions (if you can call them that) for the towbar electrics kit I bought indicated that a feed should be taken from the battery but good luck with that - I couldn't work out how you would run a cable from the battery area through the bulkhead. The fuse box is much easier.

- I couldn't work out how you would run a cable from the battery area through the bulkhead.

You don't have to run the cable through the bulk-head if you do it the way I suggest, ie from the battery down the chassis leg to

the boot, where you usually find a way into the boot

Radiotwo

Edited 10 March, 201016 yr by RADIOTWO

Thanks for the replys lads, Steve have you done a test to what current is going into the battery with your heavy wiring as it sounds as though your heavy wire is for your winch 40-50a ? I do have some 10 or 16mm singles but I think that would be over the top, like you say its handy to have an isolation relay when starting the car and it should only be powered when the engine is running -NOT ignition controlled- on my last Octavia I picked up a feed just above the pedals where there was a terminal block. Caravan this end is a Fleetwood Colchester 470/2eb 2005 which the Scout tows brill, see you on a DA meet sometime, cheers - Stuart

You don't have to run the cable through the bulk-head if you do it the way I suggest, ie from the battery down the chassis leg to

the boot, where you usually find a way into the boot

Radiotwo

I personnally would not want to run a heavy duty (or any) power feed externally underneath the car - I just think that it could be vulnerable to damage.

There is a good grommet to get through the front bulkhead - remove the panel under the glovebox and the grommet is in front of you.

You can push a rod through the grommet and then find it next to the battery.

John.

Thanks for the replys lads, Steve have you done a test to what current is going into the battery with your heavy wiring as it sounds as though your heavy wire is for your winch 40-50a ? I do have some 10 or 16mm singles but I think that would be over the top, like you say its handy to have an isolation relay when starting the car and it should only be powered when the engine is running -NOT ignition controlled- on my last Octavia I picked up a feed just above the pedals where there was a terminal block. Caravan this end is a Fleetwood Colchester 470/2eb 2005 which the Scout tows brill, see you on a DA meet sometime, cheers - Stuart

Hi again Stuart,

I have not done a test recently, but as the battery is on constant charge I don't think it would be that high, but that is relative to the state of the battery, as said before if the battery was at 10 volts (without working out) I would guess it would be about 30 amps.

You are a bit conservative on the winch currents, its nearer 200Amps, but depending on what its pulling ie pulling a two ton car onto the trailer its poss 250 amps

You say you have some 16mm cable I would use that, and get the smartcom and solves all the problems re can-bus and isolating when the Ign is off !

I see you are just in Ashton if you want some help just shout !

Steve

I personnally would not want to run a heavy duty (or any) power feed externally underneath the car - I just think that it could be vulnerable to damage.

There is a good grommet to get through the front bulkhead - remove the panel under the glovebox and the grommet is in front of you.

You can push a rod through the grommet and then find it next to the battery.

John.

Hi John.

Why would it get damaged ?

Your brake lines and fuel lines go down there and they don't get damaged ! and a few cars have batteries in the boot and run the cable back to the front via the same means.

I have used this method on a number of vehicles over the years, including 4x4's without any problems

you say there is a grommet in the bulkhead, but getting large diameter cable is going to be very hard, and much easer to follow the easy path to the back of the car

Steve

Edited 11 March, 201016 yr by RADIOTWO

Hi John.

Why would it get damaged ?

Your brake lines and fuel lines go down there and they don't get damaged ! and a few cars have batteries in the boot and run the cable back to the front via the same means.

I have used this method on a number of vehicles over the years, including 4x4's without any problems

you say there is a grommet in the bulkhead, but getting large diameter cable is going to be very hard, and much easer to follow the easy path to the back of the car

Steve

Hi Steve,

As I say, this is my opinion.

I am involved in developing and maintaining a standard for installation of comms equipment into vehicle - doc ref: FCS1362 so have a little bit of experience with these things!

It is simply best practice to run the cable inside the vehicle.

You can download a copy of FCS1362 on this page: http://www.fcs.org.uk/IndustryCodesOfPractice.aspx

Cheers,

John.

Hi John, whats your callsign ? cheers - Stuart.

Hi Steve,

As I say, this is my opinion.

I am involved in developing and maintaining a standard for installation of comms equipment into vehicle - doc ref: FCS1362 so have a little bit of experience with these things!

It is simply best practice to run the cable inside the vehicle.

You can download a copy of FCS1362 on this page: http://www.fcs.org.uk/IndustryCodesOfPractice.aspx

Cheers,

John.

But you cannot easily run 50mm cable through the car, but I cannot see where you "cannot" run the cable outside the car, other that the obvious and not to get near hot, or moving parts.

You say you are involved in comms in vehicles, do you know G4LUL ?

Steve

Hi John, whats your callsign ? cheers - Stuart.

Go on then Stuart whats yours ?

Steve

Edited 11 March, 201016 yr by RADIOTWO

Go on then Stuart whats yours ?

Steve

Well, I don't mind telling you mine! - G8SYD.

John.

But you cannot easily run 50mm cable through the car, but I cannot see where you "cannot" run the cable outside the car, other that the obvious and not to get near hot, or moving parts.

You say you are involved in comms in vehicles, do you know G4LUL ?

Steve

Hi Steve,

G4LUL - checked but "details withheld" so quick google confirms that yes I do know Brian! (had not connected him with the call sign) - have had many a discussion with him about antennas, which is what I am involved in as the day job.

John.

CQ,CQ G7MFK Calling, member of Oldham radio club, 73s - Stuart

CQ,CQ G7MFK Calling, member of Oldham radio club, 73s - Stuart

Well its a small world this radio lark, but now you both have replied I can now give mine,

Its G6YRK

But to John, do you see much of Brian ? I have not spoke to him for a couple of months, I believe he has changed his

position within the company and does not have a company car, so don't hear him as much, the only time I get to talk

to him is on the phone when we discuss our local Repeater he looks after

Steve

Well its a small world this radio lark, but now you both have replied I can now give mine,

Its G6YRK

But to John, do you see much of Brian ? I have not spoke to him for a couple of months, I believe he has changed his

position within the company and does not have a company car, so don't hear him as much, the only time I get to talk

to him is on the phone when we discuss our local Repeater he looks after

Steve

Hi Steve,

I don't actually - I only tend to see/speak him when he has some issues with an installation that involves our products - he is a very good radio man of the "old school".

I know that there were some changes where he is, I will probably/hopefully catch up with him at a exhibition in London next month.

John.

CQ,CQ G7MFK Calling, member of Oldham radio club, 73s - Stuart

Hi Stuart,

Do you have 70cm ? if so do you get on WP ??

Steve

Hi Steve, yes I do have 70cms, don't have my repeater data cards handy whats the i/p freq (just found it-your the keeper !) will have to blow the dust off the 847.will go and give you a call now ! 22.20. 73s - Stuart

Edited 14 March, 201016 yr by sparky2