Jump to content

Vehicle Wiring Regulations for Kits?


Recommended Posts

As for separate ground points for 'noisy' items - what particularly do you think is noisy? By all accounts a dedicated run straight to the vehicle negative is sensible for CB radios but that's about it.

I'd probably phrased it the wrong way around. Seperate earth for the equipment that can be effect by or malfunction because of noise, rather than seperate earth for noisey stuff. Starter, solenoid, and HT system will be major sources of noise. Relays can also cause a bit due to their coils.

Is the CB direct to reduce the audio noise you'd otherwise suffer? I remember a background tone on AM in my old VW that used to follow engine revs! In retrospec possibly the aftermarket coil and hall effect points creating a much larger voltage & spark leading to the old suppression leads being insufficient.

Cheers for the supplier recomedations, I'll look into them.

Link to comment
Share on other sites

Nice post to read having just finished wiring a 110 from scratch with a very custom loom and some extra's...

Living on the Continent means I can't say anything on the UK situation bet here it is very much up to the tester to decide if it will pass. All functions need to be there, flash rate needs to be correct etc.

2014-06-03Zekeringenboordspanning.jpg

If there is any interest I can do a write up on what I did but I must warn you - it will upset a few people as I went a bit OTT

  • Like 1
Link to comment
Share on other sites

If there is any interest I can do a write up on what I did but I must warn you - it will upset a few people as I went a bit OTT

I'd be interesting to compare notes. Like you say there will be a many/most that will not like what I'm considering either. I'm planning a complete custom dash and body electronics. There are a few reasons for this:

~ Drop voltage on dash switches to 5v or less - they may already be lower volts, not actually checked! This will reduce switch wear and chances of water causing problems.

~ Current loom has been hacked about by previous owners and don't think it will give me decent reliability.

~ Read article about just chucking full voltage at the lights takes them out of design spec shortening there life, and a significant factor shortening the life of filament bulbs is going from 0 - 100% voltage in the very short period of time it takes for relay contact to stop bouncing. This rapid voltage causes rapid heating and thus expansion. Rapid cut causes contraction, repeating causes fatigue.

~ Don't like the large bundle of wires going to the back of the car. I'd rather a larger capacity main feed, comms tx/rx, and a coms (low noise) ground. This would allow me to add an arduino lighting controller to the back and have mosfets ramping/pwm the supply up smoothly and limiting it to a peak current.

~ Bulb failure detection should be an easy add. Probably look at light sensor rather than voltage so it is less sensitive to light source type, eg LED or filament.

~ Adding an additional circuit such as a work light at a later date would not effect the main loom, just use a spare output on the light controller. Spare outputs would allow on the field swaps incase of circuit failure.

~ Whole unit could be modular allowing a spare to be carried with you. It should be fairly easy to spec a system to increase bulb life (yeah, I know LED are more reliable and I may use them, but you can't get them as easily when out and about as filament at the moment.) and on paper out last a relay.

Link to comment
Share on other sites

If there is any interest I can do a write up on what I did but I must warn you - it will upset a few people as I went a bit OTT

Definitely interest from me too! As for going OTT - why not, it's a hobby, and let's face it, the wiring in a Defender is the classic victim of 'built by Brummies, spec'd by accountants' so improving it has to be a good thing.

~ Don't like the large bundle of wires going to the back of the car. I'd rather a larger capacity main feed, comms tx/rx, and a coms (low noise) ground. This would allow me to add an arduino lighting controller to the back and have mosfets ramping/pwm the supply up smoothly and limiting it to a peak current.

Even on modern cars, certain lights (brakes, indicators) have dedicated wiring and don't rely on any sort of bus system (albeit with a bulb failure of some sorts). Not to say it can't be done, but it's a path I wouldn't go down - because I don't think it's actually much of an issue.

Link to comment
Share on other sites

Even on modern cars, certain lights (brakes, indicators) have dedicated wiring...

Thought that may have been the case which is what got me trying to figure out whether this was due to regulation/standard or generally acknowledged industry best practice. As it is a business at it's core it is driven by finance and sales figures. There are many things which are not done to cars as it wouldn't make financial sense which are fieasable for hobbyists. Take most of the mods people make to the suspension for an example, front and rear lockers, winches, underbody and steering protection...

I think the brake lights are one system I'd consider running back on a dedicated line from the switch to the lights. It could make an IVA inspector a little more comfortable and avoid any potentially awkward conversation about why your brake lights weren't working following an accident!

Link to comment
Share on other sites

It shouldn't really matter where the control box for the lights is located, I think. Many modern cars already have nearly all the lights controlled by a computer, so why not just move it closer to the light cluster? Definitely agree on the brake lights though, have a separate dedicated feed for that.

The only issue I can see is synchronisation between front and back for the indicators.

I guess the reason companies don't do it is because a bit of wire is cheaper than developing the ECUs.

Link to comment
Share on other sites

Thank you.

At the moment very busy with testing the 110 to gain trust after a serious problem with oil leaks and I need her for the Greenlane Trips to do the job. Toilet, kitchen, fridge, heating, interior etc. need to go in and please remember that English is not my native language..

http://s178.photobucket.com/user/wilderbrook/media/2014-02-23%20%20Rechter%20voorzijde.jpg.html

Link to comment
Share on other sites

  • 2 months later...

Morning all. I'm still on this, not forgotton but not had much more to say recently!

So far I've scanned all of the haynes manual wiring diagrams in and deleted all the things that I'm definatley not using. It was a long couple of hours looking through them on Saturday and I got a little confused with the interlock relays. I don't think there is a key or Transfer box lock on mine. If there is it's broke! I do realise that Haynes isn't renouned for being 100% accurate and equally my spec vehicle may not be covered but it's a good start!

While getting on with this I've tried to get an idea of when I want things on. So, permanent live (apart from battery isolators off), key in accesories position/ign/start, etc. Also looking at prioritising the devices. Bit like has been said on here before. Hazards as bullet proof as possible, then brake lights, etc. Basically safety critical parts high up, then keeping the engine running (after all it does help brakes!) and dropping all the way through to the 12V sockets. As for the CanBus system (recent arduinos can support canbus) it's not going to save myself much wiring but I haven't ruled it out. For example at the back I will need dedicated wiring for brakes and indicators/hazards but beyond that there is scope for a controller to run fogs, sidelights, work lights, interior lights, and maybe even drive a solenoid for a winch (also physically isolated further up the wiring loom).

Thought I'd hit on a gold mine with some recent mini/cheap PLCs from RS but it doesn't look like these are intended to be daisy chained easily.

As for relays, there's a lot of them on the discovery isn't there! :-o I acccept that in some situations it will be more appropriate to use a relay (like one that clicks on with accessories or ign keyswitch position). I thinnk I'll look at force guided contacts for these situations so they can be easily monitored.

Any way I'm rambling on when I need to get back to work!

Link to comment
Share on other sites

I don't get your bit about headlights/relays/voltage.

The only reason relays are added on LRs is to get the 12-14v at the light that its designed for. Its not really going to shorten the life of the filament! And neither is the fitting of the relay, defenders are one of the few vehicles to just run it all through the switch and not use a relay normally.

I also don't see the benefit of running the dash switches at 5v? Just seems like extra work for no reason?

Link to comment
Share on other sites

Nice post to read having just finished wiring a 110 from scratch with a very custom loom and some extra's...

Living on the Continent means I can't say anything on the UK situation bet here it is very much up to the tester to decide if it will pass. All functions need to be there, flash rate needs to be correct etc.

If there is any interest I can do a write up on what I did but I must warn you - it will upset a few people as I went a bit OTT

I'd be interested to read it Arjan! :)

Link to comment
Share on other sites

I don't get your bit about headlights/relays/voltage.

The only reason relays are added on LRs is to get the 12-14v at the light that its designed for. Its not really going to shorten the life of the filament! And neither is the fitting of the relay, defenders are one of the few vehicles to just run it all through the switch and not use a relay normally.

I also don't see the benefit of running the dash switches at 5v? Just seems like extra work for no reason?

Dash switches at 5V is to limit arcing and to also reduce the likelyhood of water causing problems. Reducing arcing also reduces contact wear and thus increasing switch life, or increasing reliability.

As for lights read here: http://www.powerbulbs.com/eu/blog/2012/01/how-long-do-headlight-bulbs-last

Having looked into the loom a little further I doubt I'll make much progress on that. Fatigue is a major contributor to bulb failure. Adding a ramp up and ramp down on the voltage even over a short time frame should increase it's lifespan by reducing the rates of thermal contraction and expansion.

I'd also like to fuse the starter at 500A, fuse the winch feeds at something similar, run dual batteries, and have physical isolators on the batteries. There are many 12V batteries capable of 600 cold crank amps, so a pair of them in parrallel should easily be capable of blowing a 500A fuse in a dead short.

There are many other resons why I'm looking at this, but like the work many people do to their engines or the rest of the trucks this work is for my own entertainment as part of the project.

Link to comment
Share on other sites

Dont forget redundancy on certain systems eg sidelights need to be supplied separately to either side , so that other than a fail at the switch both tail lights or front lights dont fail at the same time , likewise with main /dip lights. Been like that on vehicles since about early 80's

Link to comment
Share on other sites

  • 3 months later...

I've been working on stripping down the Discovery to the point where it can take the kit body and start work on the wiring loom. It's becoming obvious that a lot of my initial ideas may take more time than I can afford to give the project at the moment. I do however still intend to rebuild my loom and add in features for safety and reliability, such as isolation switches and such.

It occured to me last night that one of things that was attractive about solid state alternatives to relays (low current to close the switched circuit) may also be its down fall. Water on the electrics. While relays don't like it from what I've seen and read 12v circuits can generally take it so long as there isn't much in the way of ICs or other sensitive electronics? Alternators being a good example here. While they do get eaten up by lots of high water levels crossings I think this is more related to corrosion and general gunging up? So the way the relays conduct current (as opposed to mosfets where the gate is more of a capacitor) could be resulting in small leakage currents due to water conduction across circuits being ignored? After all it's common to see cars with headlights on floating in floods.

So all in all while I still like the idea of solid state alternatives I think this is not fiesable unless I find an affordable off-the-shelf product. I've seen a couple of interesting items including delphi and hella solid state relays which appear to be plug in alternatives to the mechanical relays, but I could only find a price (£90!) for the hella unit.

The specification points for my loom are now:

Fully fused and isolated - I've seen fused battery terminals and 'mega fuses' which are in the 500A teritory. Likewise marine isolators which can handle 300A continuous which should be ok for winches and starters.

Fully crimped loom - This will split people. I used to like soldering joints as it looked neater and theoretically gave a better joint but from what I've read it can cause a stress raiser in a wire which can cause the wire to fail thorugh fatigue.

Monitored / accessable test points - The machine electrical panels that I've worked on have been easy to fault find because of easily accessable terminals with contacts that can be prodded easily with a multimeter! I'd like to add a little diagnostics at a later date but not necessarily straight off. This will just mean I'll identify test points in the loom and make sure that when an electronically controlled switch (either mechanical or solid state relay) is being driven by multiple sources there are diodes in place to prevent one signal energising all of the inputs.

If anyone has any hidden gems of information with regards to low cost solid state relays I'm still lisening! Particually if they are quick enough to be used in Pulse Width Modulation circuits to remove resistors in heater or wiper (assuming there are resistors in the wiper drive - may not be the case) controls!

Link to comment
Share on other sites

  • 1 year later...

Things are getting close to bill of materials stage. Fusing like a modern car does certainly stack up the number of fuses but on the plus side I have found suitably rated fuse boxes with bus bars which means less junctions and bus bars either before or after the fuse boxes. I'm planning for the bulk of the electrics to be between and slightly back from the driver and passenger. The batteries will be under the load bay between the axles. Down side is the starter cable needs to be more meaty but frees up space under the bonnet. If I can I'll build the main fuse boxes and relays on a removable panel so I can build and test it outside of the truck. With the loom being further back it is easier to have all of the switches switching to earth to activate relays. Not too challenging but did cause a little head scratching and the buzzer requirements for the fog lights and position lights being left on a little more, particularly with removable doors, and so no door switches to trigger the buzzer!

Bit of a teaser post really. I hope to write up it and add a long overdue post to my blog.

I've taken many of your comments into account (eg ditch 5v switching etc) and am now aiming for a reliable and easy to service loom (i.e. easy to fault find, not necessarily simple!) that doesn't suffer any significant voltage drops at expected loads. I've no illusions of the loom being cheap!

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy