A few days ago we were at the Manchester Caravan & Motorhome show and we think that finally we may have found our next caravan. I posted on Twitter couple of photos and said something along the lines of “Now anyone that reads the blog will know we have been looking for a new caravan for the last couple of years and finally the @CoachmanCaravan Laser 665 ticks nearly all the boxes…“
A follower on Twitter – Venomator @Venomator tweeted back “I would be very interested to know what box/es remain unticked then?…” so this is a bit of a reply really.
One of the biggest things I have been looking out for on any caravan or motorhome is a sticker announcing that the charging systems installed are suitable for Lithium chemistry batteries. So many people have been asking me recently about changing over to Lithium and what’s involved… well quite a lot actually. There is not that much difference between a motorhome or a caravan when it comes to changing over to Lithium.
The existing shore power charger built in to most motorhomes and caravans is not lithium friendly and will probably result in either damaged lithium cells or a battery that is never really charged. So the inbuilt charger will need to be swopped out.
The solar chargers on most (not all) leisure vehicles can’t be programmed for lithium, so that will need to be replaced. And finally the vehicle charging system, which currently on most production leisure vehicles be it motorhome or caravan is not suitable for lithium batteries so a DC to DC charger will need to be installed.
All this adds up to a bit of a job and a fair chunk of beer (or wine) tokens on top of the price of a Lithium battery. I have seen lithium batteries that are advertised as direct replacements and can be dropped in place of an existing Lead acid wet cell or AGM battery but this would imply that they have charging circuits built into the battery and careful research shows the same battery and part number offered by a different vendor with no such claim to be ‘drop in’ replacements. So beware.
As I really wanted to start off a new van with a lithium set up (I can get around 360Ah of lithium for the same weight as 110Ah of good quality lead acid) but the down side is I’d have to virtually rewire the charing side of a new caravan. I eagerly await one of the big caravan manufactures to offer a “Lithium Ready” product and maybe they would like to use my label!
I don’t think it would be that difficult to achieve and due to production volumes, the additional cost would only be marginal. I expect that (or hope!) that one of the aftermarket companies such as Sterling Power or RedArc would offer something that might be a cost effective ‘box’ to achieve a changeover.
So what else was on our unticked list?
I still would like caravan manufacturers to actually go out and look at a site full of caravans being used. I can’t understand why they don’t move the electrical hook up and water at least behind the axle so it would be closer to where the EHU post is. One thing I find is having a VW Amarok which is one of the widest pickups on the UK market, on some pitches if we are using the Aquarol it’s damn near impossible to squeeze down the side. Moving everything to the rear would make it so much easier… well for us it would.
While I’m on the subject of EHU’s & water connections…. Instead of cutting lots of small holes in the sides of our vans for water and 16 amp connections… do what our American cousins do… locate everything in one locker and save on the routing out holes in the sides and adding plastic doohickeys with sliding or hinged covers. I do like the fact that some caravans now have the battery stored in a floor compartment.
The other one that missed the tick box was the lack of being able to sit in front of a mirror…
Not a deal breaker for me… but Sue thought that if they had made the mirror so it could swing round either way to face each bed that would have been ideal. Some of Swifts offerings have got it spot on with a mini dressing table. Coachman however have conveniently located a socket for hair dryer/straightners. I did wonder about having a small stool or seat spanning across the two beds… but think the mirror swivel is a much better idea. Maybe it’s something that could be added as an after market item using a swivel TV bracket maybe”
Now… anyone know where I can buy some cheap lottery tickets…. hello… anyone….
My email box tends to get a wide variety of questions covering all sorts of subjects. The most frequent one is to do with wiring and electrically related problems. Sometimes trying to diagnose issues via email and a few photos is a bit of a challenge, but hey who doesn’t like a challenge! One thing that I do see a lot of is electrical work that is…. well, quite frankly not up to scratch in my opinion. So here is my attempt at a basic guide.
You have to have a plan.
So many projects start by adding one or two things… extra 12 volt outlet here… maybe another light and then something else comes along that needs adding in. Before you know it you have a mess of spaghetti that the local Italian restaurant would be ashamed of. It is all too easy to fall into the trap of adding circuits to existing fuses…. or installing a new fuse and a few weeks later adding another circuit to it as it’s easier than installing another fuse.
You can download these and other drawings from the Electrical Drawings page in the drop down menu under “Document Library”
You need to draw out how the major elements are going to connect together – leisure batteries, solar charger, DC to DC charger, inverter and include all the big fuses, buss bars and fuse box. Don’t think about where any of this goes for the moment just get the basic layout and how everything interconnects worked out. It might take a few goes but paper is usually cheaper and less frustrating than sorting out the mess afterwards.
Once you have all that figured out you can start working on the details… just how many fuses will be needed… and what ever number you come up with add half as many again as a minimum. Having a few spare fuse positions that maybe never used is way cheaper than in twelve months time having to install an additional fuse box. A this point you can start adding details…. what size cable is needed for each link, what sort of fuse box do you need.
You can also now start to think about specific facilities you might need. For example, many overlander vehicles will have a button on the dash that when pressed and held down activates a high current relay that links the house batteries to the engine cranking battery. Very handy to have… jump leads are not much use if you are 200Km from the nearest vehicle. If your only trip ‘off road’ however is the muddy car park at the local car boot sale than maybe not a priority.
Don’t use the vehicle chassis as a ground.
Modern vehicles are constructed using different materials and quite often panels and sub frames are glued together. Back when virtually all the panels were spot or seam welded steel, using the body and chassis as a ‘ground’…. which really isn’t a ground but the neutral return path… this was acceptable. However now, sections can be glued together and are often sub assemblies of aluminium and other light weight materials bonded together. Just because you see a neutral bonding point (earth terminal) don’t assume this is is capable of being a suitable point to bond the neutral side of a circuit or accessory you are installing. Modern vehicles often have small bonding straps between sections that can carry the current that the vehicle manufacturer rated the bonding point for. Adding additional equipment and accessories might exceed the original design spec.
I did see a spectacular failure due to a 3000W inverter having it’s neutral lead ‘grounded’ in the rear of a vehicle. Running at about 2000W the neutral side was trying to ‘return’ a current of about 170 amps through the body of the vehicle, which lead to serious damage to some of the vehicles wiring and a number of vehicle components… and a ‘repair’ bill of nearly £1500.Putting a riv-nut in a body panel that is mastic bonded to the body is not a suitable negative bonding point!
Additionally a number of vehicle circuits are now negative switching or operation and installing additional equipment or accessories could have unforeseen issues. Always from any accessory or piece of equipment you install, add the neutral return path back to a suitable single common point or buss bar you install for the purpose and connect this directly back to the leisure battery.
Ideally all the ancillary leisure circuits should never rely on any of the vehicle wiring and the negative side of the leisure wiring should only ever connect to the negative side of the leisure battery.
Don’t use battery terminals as a junction post.
Both the leisure battery and engine battery should only have connections that lead to either in the case of the positive terminal a master fuse /circuit breaker and isolator switch. The negative terminal should only have the connection to a master negative terminal point or buss bar.
If you want to install any sort of battery monitoring, it is convention to install the shunt on the negative return to the battery between the negative buss bar and the negative battery terminal. If you have multiple circuits terminated on the battery terminal it makes future changes and upgrades, including installing a battery monitor very difficult.
Using the battery terminals as connection points for multiple services also makes fault finding very difficult. Each circuit may or may not have it’s own fuse and it’s difficult to isolate circuits….. plus I’ve had enough sparks flying round when trying to disconnect a battery because someone did not install an isolator to know that it’s only a matter of time before one goes ‘pop’.
Please, just don’t do it.
Have a think on this. If you had to go to an auto electrician to get a fault traced and corrected, they would immediately put at least an hours time on the invoice just to figure out what was going on with all the cables on the battery. Also, If you don’t have a battery master isolator installed, get one installed now. It’s a safety item that must not be missed out. Having the ability to quickly turn off all the leisure circuits in an emergency might just save you from the unthinkable happening.
Every cable should be terminated. Period. There shouldn’t be any cables in an installation that don’t have a crimped (or soldered) termination. Even if it’s a screw terminal such as those found in joining blocks or 13 pin plugs.
If you are embarking on a wiring project, its always best to start building up your stock of terminals. I usually buy selection boxes of terminals on line and supplement these with bags of single type connectors for the more commonly used ones. To keep everything organised tote organiser boxes are my preferred option.
There is nothing more annoying than running out of the something and its always just as you want to finish a project off so you end up cutting corners.
For some of the larger cables, if you don’t feel up to making your own terminations there is usually a local auto electrician available that will terminate them for you for a small charge. However, a crimping tool that will terminate up to 50mm cable is not that expensive – around £27 and will probably work out cheaper in the long run. I’ve a link to the one I bought via Amazon and regularly use in the SHOP page.
Get the size right…
Selecting the right size or gauge of cable is critical. There are two factors that determine what gauge of cable to use for a installing any particular circuit. The maximum current that’s going to be drawn and the length of the cable. Once you have selected the right size cable then means you can select the right size fuse for the circuit. Never fuse a circuit greater than the current capacity of the cable.
You can download these and other drawings from the Electrical Drawings page in the drop down menu under “Document Library”
I generally tend to list what is going to be installed, then work out all the gauge for the cables for the circuits. From there it’s easy to see which is going to be the most popular gauge and rather than buy several different gauges of cable try to select a limited selection of gauges.
Always go for the safe option of over specifying the gauge of cable for any particular circuit. If it’s a 10 amp circuit and you have used cable suitable for a 16 amp circuit, it doesn’t mean however you need to use a fuse greater than the 10 Amp circuit requires.
Something else to consider too. Most 12 volt cables are copper, however if you are installing them in a less than ideal environment, such as a boat, you may want to opt for tinned copper cables. These are far less susceptible to cable corrosion. Even in the best marine installations I’ve seen copper cables corrode through in less than a couple of years.
Cardinal Sin! – Never ever use two smaller cables to make up the equivalent of one larger capacity cable. You would be surprised how many times I’ve seen this… sometimes done by “professional” tow-bar installers when reported poor leisure battery charing or poor fridge performance is reported and the voltage drop is too great.
Wiring Looms – wrapping it up properly!
Dressing cables into looms is not difficult nowadays. There are many options available on the market to help you produce a professional looking finished product. I personally like for looms within the vehicle using a felt finished looming tape. You don’t wrap it so it overlaps but at a sharp enough angle so as it spirals round the cable bunch it leaves some of the cables exposed.
Felt is good as not only does it keep the loom together, it allows quite a bit of flexibility and prevents cables from rubbing or banging on flat surfaces making a noise.
For any cables outside the vehicle body there are two options depending on use. In the main I’d go for split tube conduit. It’s available in various sizes and can be bought in either cut lengths or rolls. The other option is to use self amalgamating tape. It looks like ordinary PVC tape but as you wrap it round you stretch it and it releases a chemical which when overlapped onto its self becomes a permanent bond, effectively making a sealed tube. It is generally however fairly inflexible. Both have their place.
Anything in the engine bay or underneath the vehicle I use split tube and generally only resort to self amalgamating tape to seal inline joints.
Relays….. yes or no?
For me its Yes. I much prefer locating all the relays in one place therefore minimising the amount of heavy cable. By using relays to do the heavy switching you can use smaller and sometimes more attractive switches. I have in the past used 7 core trailer cable to connect 4 switches including LED indicators back to a relay bank rather than make up a custom wrapped loom.
You can download these and other drawings from the Electrical Drawings page in the drop down menu under “Document Library”
It also makes tracing faults easier, as it’s simple to test if a switch is working, you can hear or sometimes feel the relay operating as you operate the switch. Its unusual to have a fault with a relay but quite simple to test… just unplug and swop over with a known working relay. If all the relays are located together it makes this task and testing the feed to the relays so much simpler. From that point all you need to check are the two wires going out to the device and the device itself.
Obviously some circuits don’t require a relay or if it’s designed to be turned on for a long period… such as a diesel heater, then adding a relay will just increase current draw, albeit small, on the leisure battery. A bit of common sense can easily determine if you should opt for a relay or not.
Grommet?…(no not Wallace’s friend!)
Whenever a cable or cables pass through anything solid you should use a grommet. You would be surprised at the amount of damage I’ve seen to cables due to either not installing a grommet to an insufficiently sized (too small usually) grommet.
When ever I pass either a cable or loom through a bulkhead for example I like to supplement a grommet with a bit of heat shrink sleeving over the cable as well. Even passing a cable through an existing grommet from the engine compartment to the interior, adding a length of heat shrink sleeve won’t do any harm.
Having a handy selection of grommets available before you start threading wires through is far better than trying to install protection afterwards. You’d also be surprised at how many cables I come across that have been damaged while pulling through holes in metal and wood panels. Always better to start with a grommet or two! Where a cable or loom passes through a grommet, it’s aways best practice to try and anchor the cable or loom either side of the grommet to something solid using “P” clips. This will reduce the chances of ‘fretting’ with the movement of the vehicle.
While we are on grommets…. a quick note about cable-ties (zip-ties). Stop doing them up so tight! I’ve come across cables cable-tied to a chassis rail so tight that the cable-tie has cut into the insulation and is fretting the conductor inside. Cable-ties are generally made out of a harder plastic than the cable insulation so will over time wear away at the insulation.
Get yourself a cable-tie tool that not only allows you to precisely control how much tension you put on the tie but also cut the end off so that there isn’t a wrist slashing booby trap lying in wait for some unsuspecting person. I use a fairly cheap pair (left). I think they were around £8. So not really expensive. But they make a nice neat job of installing multiple cable ties with the correct tension and the ends cut cleanly off level with the lock tab. You can buy ones that have a tension dial built in so you can set them to a pre-tension, but I find after a bit you know just how much to squeeze the handles to get the correct tension.
So what is the correct tension… well if you are doing them up so tight an elephant could dangle on the cables then that is too tight. They should be tight enough so as not to slip but you should be able to spin them round the cable(s).
Cable-ties really should not be used to make looms or anchor cables or looms to anything solid. If you want to make a loom, wrap it in specialist loom tape. If you want to anchor cable or a loom to something solid use a “P” clip. If required… use a length of heat shrink to make the loom a tighter fit in the ‘P’ clip.
I know you are dying to ask…. when do I use cable-ties? Well generally at the installation stage to get things to stay in place before installing P clips or if I have to run a new loom along the same path as an existing loom, I generally opt for cable-ties to hold them both together (as long as the original is suitably anchored to support both)
While we are talking abut cable-ties… I have seen the worst kind of mistakes in the use of them. It is not OK to cable-tie anything to brake lines, fuel lines, vacuum lines, hydraulic hoses, coolant hoses or steering components (yep one bright spark cable-tied his front LED light bar wires to some of the steering components!)
Heat Shrink Tubing
An absolute must have in my opinion. There are two main types – plain and pre glued. The plain are the main one you would use, while the pre glued are great if you have to over sleeve a connection to make it waterproof. As you heat up the pre-glued type, the glue softens as the tube strings and bonds to the cable as everything cools. They can be a little more rigid when installed, so make a service loop in the cable. The finished covering is usually waterproof enough for brief submersion if done correctly.
Having a selection of sizes and colours is handy and assortment boxes of multiple sizes and colours can be bought on line cheaply enough. In the workshop I use an old paint stripper heat gun on low power as I find that is more controllable than a flame.
Bridging the gap… something in the future?
Although not so common in the UK, in Australia and the USA wild camping (boon docking) is probably as popular as campsites. To this end trailers and caravans usually have much larger battery capacities than anything found in Europe. It’s not uncommon to find outfits with 600 to 800Ah battery banks recharged mainly be solar, buy increasingly (especially in Australia) an additional bridge between tow vehicle and trailer is made using heavy duty “Anderson” connectors and cables capable of supplying upwards of 60 Amps from the vehicle to the leisure battery bank.
With the cost of lithium batteries reducing almost daily, I can foresee very soon that light weight lithium batteries will be installed in caravans. The down side of this currently and trying to retrofit Lithium is the existing charging setup of current European vans is not really suitable for looking after these type of batteries. We have a Sterling Power Wildside unit installed in our caravan which allows us to charge any type of battery chemistry, including lithium when connected to the tow vehicle. The draw back is the caravan’s inbuilt charger is only capable of wet lead acid or AGM. I think that a high capacity DC to DC charger installed in the vehicle and an additional cable to supply the caravans battery banks may not be too far away. It’s something you might want to keep in mind for the future. It’s something I’m looking into currently.
Well, that’s a bit longer than I anticipated and there is still a few things to cover. If you made it this far…. take a toffee out of the jar… well done! If you think I missed something or would like me to cover something specific, drop me a comment below.
The problem with information on the internet is that although there is some great advice to be found there is also some less than great…. poor… really really poor advice and sorting out the good from the bad is sometimes not easy.
We are currently pitched on the Caravan & Motorhome club site Beechwood Grange near York and I decided to sit down and pen this post as for the last few months I seem to have been sorting out a number of problems via emails and phone conversations that really should not have arisen.
I’m going to give you a couple of examples of what’s been dropping in my inbox. To protect the inoccent I’m not going to name anyone or the channels. I do have the OK to relate these issues.
“Hope you can help, I’m converting a VW Transporter into a camper van and have been following a number of YouTube channels for information on how to do it. It’s nearly complete but I have a problem when I go to use my inverter off grid. The base of the seat starts to warm up and a get a funny smell in the front of the van”
After an exchange of emails and a few photos were sent I eventually worked out what was going on. The 2000W Pure Sine Wave inverter was floor mounted in a cupboard towards the rear of the van where it was convenient for the mains sockets on the inverter to be reached. A suitable size Positive (+ve) lead ran back to the two 100Ah AGM batteries located under the front seat. A suitably sized Negative (-ve) lead also ran back to the batteries and was bolted to the chassis under the seat along with a number of other smaller -ve leads. The batteries were mounted on a wooden platform above this connection. The +ve lead from the inverter went to one battery +ve terminal and a link wire to the second battery +ve tied the two together. The size and rating of this tie wire was a lot less than it should have been.
The -ve posts of each battery had a very short 10mm2 cable going to a threaded stud mounted on the base of the seat and were helpful on to the stud by a star washer and nut. The seat base was a 3rd party metal fabrication hat had been powder coated and bolted to the vehicle floor by 4 bolts and ‘penny’ washers.
What was going on?
When the inverter was operated, it drew current from the battery down the +ve lead. Apart from the fact there wasn’t a fuse between the battery and inverter this side of the circuit was OK. The return path however was a different story. The inverter -ve lead was connected to the vehicle chassis under the seat – not at one of the seat mounting points. The -ve of the two batteries was connected to a stud that was a press fit into the seat base. It didn’t have a hexagonal head just a mushroom head. It was also way under size for the terminals that were fastened to it. The oversize star washer stopped the nut pulling through the terminals. The return current path therefore had to flow into the vehicle chassis, up the four bolts holding the seat to the floor and through the seat base to the push fit stud and finally into the two short leads connecting the battery -ve terminals. The relative high current drawn by the inverter through the single undersized push fit stud and the four floor bolts that were securing a powder coated frame with penny washers presented enough resistance for 60 or 70 Amps of current to start to heat things up a bit and burning off some of the powder coating. 70 Amps passing through a 0.1 ohm resistance will generate 490 watts of heat (calculated using R x I2 = P) this is why it’s critical to get any cabling correctly crimped with the right terminals for the job.
Don’t rely on the vehicle chassis as a return path. install cables for both ‘legs’ of the circuit from source to destination and back again.
There wasn’t a fuse installed near the battery. Any cable coming from a battery MUST have a fuse close to the battery before it goes off anywhere to supply anything else.
If a cable terminal requires an M4 nut and bolt…. use an M4 bolt nothing smaller will do.
If you are ‘grounding’ to anything metal, clean the surface, use a dab of protective dielectric grease (there are different ones for steel and aluminium!) and make sure any washers used work correctly. Flat clean washers for electrical contact and a star washer as a mechanical anti vibration measure to stop the nut loosening.
“When ever we have been away for a few days off grid on the return trip there always seems to be a strange smell coming from the engine compartment. We have a self converted T6 camper and 400Ah of AGM leisure batteries with 240 watts of solar on the roof. After watching a couple of YouTube installations of DC to DC chargers I recently installed a Redarc DC to DC charger to help keep the leisure batteries in good condition and fix some issues I was having with the smart alternator”.
OK again after several email exchanges and a couple of video clips I got to the bottom of this one as well. The RedArc unit is capable of charing at 50 Amps and to do this pulls around 55 to 60 amps from the vehicles alternator. However there are a couple of issues in doing this. One of the first things that the Car Audio guys always recommend before installing any of the mahoosive bass pumping amps in vehicles is to replace and upgrade three essential cables. The first is the cable from the alternator output to the battery, the second which might not seem so obvious is the ‘earth strap’ as it is sometimes called from the engine to the vehicle chassis. This need either replacing completely with a larger cross section and also where it terminates on the vehicle needs altering. Usually the Audio boys install a new cable from the alternator mounting bolt directly back to the negative battery terminal*. Why” Well quite often the engine earth strap is just a simple copper braid strip sized just big enough so the starter motor current won’t burn it out for the 5 to 10 sends the starter is operated. You start trying to push the engine battery charing current and the additional 60 amps for the DC to DC charger through it, it starts to get warm. Not a problem as usually it’s not covered in a PVC jacket and hanging down in a bit of air flow under the engine. So the Audio guys change or upgrade it and they pull more current than we do. The third and last one that is upgraded is the short stubby battery negative lead going to the vehicle chassis. For our purposes, not really a necessity but hey ho.
*A note of caution. On most vehicles now there is a shunt between the large negative cable going to the battery and the negative terminal of the battery. This allows the vehicle ECU to determine the current flow in and out of the battery. It is important that you only connect any ancillary equipment to the cable side of this shunt and not to the battery side.However some DC to DC chargers specify you connect to the battery side of the shunt. Please refer back to the instructions with your particular unit.
What was going on?
Well basically the negative side of the circuit was getting a bit warm and the lead from the alternator was running at virtually it’s maximum rating. What you have to remember is that the vehicles electrical system is really designed down to a price and to do just the job of keeping the vehicle running. As soon as you start to ask a bit more of it you are stressing some elements and you have to consider all aspects and upgrade parts sometimes.
Adding an additional earth strap from the alternator mount directly to the chassis side of the shunt on the negative post of the engine battery and upgrading the alternator positive cable made a big difference and there is no longer any smell after a couple of hours of charging from the engine. Apparently starting the diesel engine has been improved with the report: “it seems to turn over a lot faster when starting” so maybe there was an underlying issue with engine earthing somewhere?
My two cent’s….
Don’t use the vehicle chassis as a neutral return path for any additional equipment you install. Modern vehicles are not so much welded as bonded together and some have aluminium or plastic body panels. Additionally even the steel they are made from is not as good a conductor of electricity as copper. Leave the vehicle electrics to the vehicle body and install your own neutrals.
Don’t ‘ground’ the leisure battery to the vehicle body. Keep the leisure battery circuits isolated from the vehicle body. Run a suitably sized neutral cable directly from the leisure battery to the vehicle battery.
Don’t use leisure battery terminals as a place to connect everything. Use a proper terminal bus bar block for live and neutral connections. The only connection on your battery terminal should be the main conductor going to either a second battery or a bus bar terminal block. The only exception to this is for battery monitors!
Don’t assume the vehicle electrics are up to the job. Most vehicle electrics do the job they were designed to do and not much more. As soon as you start asking the alternator to charge another one or two 100Ah batteries you are ‘stressing the system’ to a greater or lesser extent. Some big 4 x 4’s can handle this, some smaller vans might not be able to. Consider what you are installing and think about how the vehicle will handle this and look to see if anything needs upgrading.
Know what cable terminations to use and where. Also don’t cheap out on the correct terminal installation tool. If you are building or converting a camper van is it worth saving £25 on a proper ratchet crimp tool?
Don’t watch someone on YouTube do something and assume that if you do it exactly the same way it’s going to be right. It’s interesting on how many times people make a video on wiring or installing equipment and follow it up with “if you want to know more go and watch so and so’s video about it. He produces really good videos how to do this” Just because someone produces really good videos doesn’t mean the videos show how to do something correctly. It’s only how they did it, not an installation bible. You have to do your own research and learn to sort out the good guides from the bad.
I have watched an awful lot of YouTube motorhome refits, camper van, step van and bus conversions etc and a lot of the electrical installation – especially on the 12 volt side is poor in my opinion. I’m not an expert however and I’ll only ever say how I’d so something and the rational behind why I’d do it that way.
Just throwing this out there to see if there is any interest….. I was thinking about doing either a small forum on the blog or a Q & A page as a resource for some of the electrical ramblings. Would that be of interest/use to anyone? I do know that quite a few of the electrical drawings I have done have been downloaded and again wondered if specific drawings for equipment would be useful. Let me know in the comments below.
A short while ago two people contacted me separately asking if I had any information relating to rewiring restoration caravans so that they could plug into a modern 13 pin electrics tow car and take advantage of leisure battery charging and run a modern fridge or coolbox.
This was followed up be someone asking me how they could upgrade a late 1970’s caravan and still incorporate and use the “CAR-VAN” switch to change between using the leisure battery or vehicle battery.
I came up with a couple of drawings that covered the basics to show how they could be upgraded to modern tow vehicles. The one above is a basic ‘front end’ from 13 pin plug back to a fuse block for the road lights and a habitation relay.
The drawing below add in the option of a “CAR-VAN” switch (sometimes labeled as CAR-CARAVAN) which uses the same 40 Amp relay as the habitation relay rather than a chunky high amp switch found in some models. However installing a CAR-VAN switch does have limitations… for example you could not install an inverter.
If you want to download these drawings (or any others I have done recently) they are now in PDF format sized A3 and can all be found on the “Electrical Drawings” sub menu below “Document Library“. I kept getting emails asking where such and such a drawing was, so I decided to put them all into one place.
I don’t normally do electrical drawings for specific projects (unless being paid), however if you have something that you think might be of interest to a wider audience drop me an email.
I fitted the ProVent to our VW Amarok when it had done about 8000 miles (12,800Km) and we have now done just over 13,000 miles (21,000Km) a great deal of it towing. I opted initially to drain the ProVent every 600 Miles (1000Km) and the first three each time I got about half a cup of slightly oily water. It was clear like water but when rubbed between your fingers it felt ‘slippy’ a bit like baby oil. I did notice that one draining that covered two long tows up to the Lake District what came out was slightly darker, still about the same quantity though. However I did notice on the last draining I had more of a dark oil content as a separate layer in the lighter clear ‘oily water’. Watching the video below I did find out that this is normal. The filter that is in the ProVent takes a few hundred Km to start working properly, first catching the condensate and then once the filter is saturated does it start to catch and drain the heavy oil.
I did recently remove the hoses on the intercooler (inlet and outlet) just out of curiosity and the interior from what I could see was still clean, with only a light covering deposited from the first 8000 miles (13,000Km) of running without a catch can fitted.
So how much have I got out?
Well in the first 5000 miles (8000Km) I have now filled an old 500ml 2 stroke oil container and just started on my second. I’ll continue to drain at the 600 mile mark. Although I must admit I now drain it before a long towing trip and again when I return home. It only takes about a minute and doesn’t require any tools so really is one of those tasks that is easily accomplished with the minimal of effort. Hopefully this will keep our engine in tip-top condition and not start to suffer from the oily carbon build up that saps power and is prevalent in all diesel engines.
Here’s an excellent video from the guy’s at 4WD Actionwith probably the best explanation I’ve seen so far on the net… (Video (c) 4WDAction.AU)
I seem to have had an increase over the last few weeks of emails from people involved in building, modifying or upgrading Overland Expedition type vehicles. I think some of my posts must have been quoted or referenced in related forums. A lot of questions are related to roughly the same group of topics so I thought I’d produce three drawings to help answer the bulk of the questions. If you read down the comments on some posts I have answered a lot of specifics that might help. I’ve merged a lot of the questions into a paraphrased ones…
“How can I get my LED light bar and spotlights to come on when I use my main beam switch but I want to disable them when on the highway?”
The questions were from a number of 4 x 4 Off Road enthusiasts and Overland vehicle people. Simplest way I could come up with was using a couple of diodes (details on the drawing) Three switches… one for LED Light Bar, One for Driving Lights and one that allows you to sync the LED Light Bar and Driving Lights to the operation of the main beam in the vehicle. Flash the main beam and with the Sink Switch ON… all the lights will flash. Note… this may be illegal in some countries, so having the option to turn off the facility when on the roads ‘should’ keep you within the law…. don’t quote me on it!!!
“Whats the best layout for connecting a solar controller / inverter / isolation switch to my battery bank?”
The best schematic I could come up with that is flexible for most situations. I’ve put a few notes on the drawing. The various components I’ve drawn generically…. all can be found at your preferred supplier.
“What’s the basic layout of the vehicle fridge and leisure battery charing circuit?
This I think has come from a few on-line discussions relating to poor performance of the fridge and leisure battery charing in older 4 x 4 vehicles. I was receiving for a while a number of questions related to upgrading older installations. I also receive a number of emails asking how to add the facility of fridge and leisure battery charging to older vehicles and upgrade the 7 pin tow socket or old military lights socket.
You can download the PDF’s and are free to use for personal use. If you post them on other forums I’d appreciate a link back to this page and/or an acknowledgement.
I’d appreciate any feed back in the comments below.
A couple of eagle-eyed mirror aficionados have spotted that we use Milenco Grand Aero 3 towing mirrors… but they also spotted that there was something different about the mounts. OK I’ll have to admit you are an eagle eyed bunch!
On the Amarok, the mirrors are quite big and if I get them adjusted about right I can just see down both sides of the caravan… we’re not 8 foot wide. However, driving without mirrors is more likely to attract attention and it’s easier and safer just to fit a pair. I first went for a brand that I’d used on the Land Rover Freelander, however the Amarok’s mirrors are quite deep and it wasn’t till I tried them that I realised how much of an issue that was….
The other issue I had… I didn’t particularly like the fitting….. it was about on the limits of extension and about 25% of the mirror was obscured by the Amarok’s door mirror… just at the point the would allow you to see the wheels of the caravan. Not ideal.
So I looked round for a mirror that would move the face of the mirror rearwards in about the same plane as the normal Amarok mirror. The added depth of the Milenco Grand Aero looked as though it would do the job perfectly.
Actually it was a little too much. As the mounting for the mirror was now on the door mirror plane, not as the previous mirror the back of the mirror housing it shifted the face of the Grand Aero too far rearwards. I liked the vision the Grand Aero gave and the mounting.
To the Bat Cave…
I just happened to have some lengths of 12mm steel tubing and a bending tool. Maybe I could solve the problem without searching round for other products.
I used a welding rod to hand bend a profile that seemed to put the mirror into the right position. I worked out I’d only need two bends to get the mirror in the right position.
I installed the two mounting brackets on the door mirror in the final position I wanted them and slid a length of tube into them. Marking where I wanted the first bend to be and using an angle finder to approximate the angle that would move the mirror far enough forward so the face was in line with the door mirror face… this then gave me the point to start the bend upwards to get the mirror at the correct height.
Ok before I get a lot of comments asking why installed the mounts on the lower edge of the mirror… two reasons…. if they do move about or squish down on a bit of grit any scratches won’t be seen in the painted area of the door mirrors and from the driving position they don’t obscure my view if I have to look past the top of the door mirrors. I’ve also noticed when its raining I don’t get nearly as much water running down the face of the door mirror. And another reason…. the bottom of the door mirror on the Amarok is not quite as curved and the clamps fitted more securely. I’ve got everything dialed in now to the point where I don’t actually need to adjust the mirrors each time I fit them.
At this point I hadn’t cut the tube to length on the vertical section so I had the chance to adjust the height of the Grand Aero. After a bit of trial and error that involved a clamp and running round to the driver’s seat… and back again to adjust I got what I thought was the right height for me.
As you can see in the photo above, the reflective face of both mirrors is in near perfect alignment… and for me that makes it easy when driving as I don’t have any perceived shift in focus. The picture below is from the drivers position… I put the camera as close as I could to where my eyes are and I get a great view rearwards. Note that installing the mounting clamps on the bottom edge of the door mirror does not block the forward side view over the door mirror.
The driver’s side was bent the same… just opposite ‘handed’ and the length worked out right for the height too.
When seen from the front… even though I’m not quite ‘square on’ to the caravan, I’m angled slightly to the left when sat in the drivers seat, the mirror is fully outside the extended side line of the caravan giving me a great view.
I gave the now bent and drilled tubes a light emery and de-grease followed by couple of coats of grey acid etch primer. This was topped off a few days later with a fine bed liner spray. This game the arms a durable coating plus the bed liner finish is quite ‘grippy’ and allowed the clamps the hold fast without too much yanking on the knobs.
We have been using these now for about two years and for me they work out just fine.
I had all this stuff in the Bat Cave as it was purchased for other projects, so the mirror arms didn’t really cost me anything. Both arms were made out of one 1 metre length of 12mm steel tube.
The tube bender I paid less than £30 for it about 12 months ago from Amazon. The 12mm Steel tube, again from Amazon was around £4 for a 1 metre length and the Truck Bed Liner paint was around £8.
It’s that time of year again, a few days before the opening of the North’s biggest caravan and motorhome show and the first of the New Year at Manchester’s Event City and again we are sat thinking about changing the van this year. Mind you we were convinced last year… and the year before we were going to change the caravan.
In 2017 we went to the shows, round dealers and almost did the deal. However a few things just kept us from signing on the dotted line. We also came close last year, but again there were design elements that just didn’t sit right with me.. or t least would make me compromise more than I wanted to.
So here is my guide to any caravan designers out there working on the 2020 design that they hope is going to be the next winner.
Looks and sounds good…
A locker containing a TV swing out arm…. OK stop watching American RV shows right now. What were you thinking guys… We don’t sit round campfires watching TV in the middle of the Mohave… honestly we don’t. If people want to watch TV in their awning I’m pretty sure they will have come up with a way by now that suits them. It’s not even like you designed the thing so that you could leave a 24 inch TV permanently mounted and closed away securely in the locker.
While we are on the subject of TV’s…. stop putting the radio in a cupboard in the front of the caravan… put it near where you provide a TV mount. A lot of thin screen TV’s have poor speakers and a great solution that many caravaners opt for is connecting the TV sound to the radio AUX input… but a lot don’t because it becomes a major challenge routing a pair of screened wires round and through all the cabinets. Make it easy, put the radio near the TV, install a AUX jack and sell it as a feature!
Right, which designer is going to own up to designing a storage space in the wardrobe in the rear bathroom of a van to store the table. Did you design the van and at some point while you were stood at the coffee machine someone say to you “Dude I didn’t see where you stored the table in your design” and you immediately rush back to your workstation and in a panic put in the wardrobe in the rear washroom.
Have you ever had to get a table out, and set it up with a caravan full of people balancing drinks when some one is shooting “PLEASE SET THE TABLE UP NOW… DINNERS READY”
It’s on the other side…. or end!
Right I want all designers to go and stand on empty pitches at five caravan sites and look round. What do you see? Bollards…. you read that right Bollards… at the rear of the pitch. Why there you may ask? Well designing a site or upgrading a site if you can avoid digging across a pitch to install services it tends to be cheaper and easier to reinstate the ground afterwards, so most are laid out that way for cost and convenience. Is been like that for quite a few years. So why do you insist in keep designing the power, water connections at the front of the caravan… and some of you just for good measure put one on each side. If you take the common size pitch and park your caravan in the middle throw up a mahoosive flappy tent thing on one side and connect up your Aquarol (other water containers are available) then try to squeeze your tow car down the other side – that is if you have the room with an 8 foot wide van – avoiding parking so that vehicle door can actually open without bashing the water container or the passenger can actually squeeze past.
Here’s an idea….
Here’s an idea…. put the water inlet and power inlet on the rear off side corner and while you are at it check out how American RV’s have a locker with all the connections inside and a convenient opening in the floor to pass the connections through. That would save cutting holes and installing expensive fittings. While you are at it moving the water about, here’s an idea, install a simple Hozelock fitting with a check valve and pressure regulator so when on a device pitch, rather than expecting customers to buy expensive adaptor fittings, they can just buy a cheap food grade hose to hook up. Could this be the next USP I wonder?
To off grid or not to off grid?.. that is the question.
I applaud the designer that moved the leisure battery from a side locker to under floor mounting and moved the gas bottle from the front to the side. Heavy items, get them low and in the centre I say.
However, next year go one step further… make the battery locker bigger to accommodate two batteries and ready for Lithium… which may mean insulating them. Nearly all caravans are sold now with solar panels, but it would be nice to be able to choose to install an additional battery to take advantage of the solar without having to start installing aftermarket sealed and externally vented battery boxes.
It’s behind you…
…. well it might be but I can’t see it. It’s time to offer a rear view camera option on all caravans now I think for safety’s sake. A lot of motorhomes are offering it as an option or a standard fit. While it is fairly easy on a motorhome as the display choice is dictated by the designer. For a caravan it’s slightly more complicated as some vehicles have rear view systems built-in, some have nothing so how do you decide what to install? Simple really.. most systems use composite 1 volt peat to peak video and there are dozens of components out there on the internet that allow this to be digitised, scrambled, flipped and sent vis radio, bluetooth, over power feeds and via IR so it can’t be that difficult or expensive to install a system with a remote screen at a sensible price point. The biggest hurdle for anyone contemplating installing a rear view camera system is actually mounting the camera on the caravan body and running all the cables.
Unless you have towed a trailer with electronic brakes you will never know how horse and cart our current over-run hitch brake system is. In the land of the… that lot over the pond, have been using electrical braking systems for a while and in the land down under (Straylia… YESSSS….. for John Cadogan fans) ALKO have been offering a system for a number of years that is really just an extension of their caravan chassis ‘kit of components’ and could easily be adopted for European component chassis.
Now a lot of you know from my past volumes of scribblings I kind of enjoy delving into caravan dynamics and I really want a caravan with electronic brakes. OK before the comments come stating that under current regulations you are required to have over-run braking system etc etc…. yep I know. However from my poking around this subject for over 18 months now, it seems that you can fit electronic brakes as long as the existing over-run setup is retained.
If you are still reading this go and check this out from seven years ago about a system that was going to be produced….. if I was setting this cones out I think I’d be going changing my undergarments…. www.youtube.com/watch?v=pIB7Rmhll9s\
Right, I wanted to keep this down to a short 1000 words, and I failed as it’s over 1300 now. I hope you have all had a great Christmas and may 2019 bring you new touring adventures and memories. We’ll see you on Thursday 17th at:
After a quick four-day break at the Caravan & Motorhome Club’s site at Wirral Country Park (excellent by the way… already trying to work out when we can go back!!) and a bit of work getting in the way it was time to get going again not he catch can… really it should be called the “Air Oil Separator” Install.
Last time, I’d decided if IKB would have been shaking his head… then it wasn’t right. I decided to make a new bracket out of 1.8mm aluminium sheet and go into full on origami mode. (ps.. after the last post someone emailed me asking what IKB was…. Mr Brunel was not pleased).
I wanted to make a bracket that passed under the air con pipe and bonnet cable release fitting so that it cleared everything and gave good access at the same time. As a test I did a trial bend if some 1mm thick steel I had just to get the shape…
Once I’d got the angles and size sorted it was time to move on to the aluminium sheet. My press brake… well I call it a press brake, in reality its a cheap basic hand folding machine but it works very well as long as you know its limits and don’t get daft trying to fold big stuff. It was all about the angles…
The first two were easy and I could form the lip with two folds, the second was less than 90 degrees so I just about got away with enough clearance. However folding the return that would lip over the front cross brace which was also less than 90 degrees also meant that I’d have a problem fitting it in the folder.
However, a little lateral thinking and taking the blade off the folding machine, inserting my workpiece and re-installing the blade meant I could fold in the opposite direction (downward)… result!
A quick trim and rounding off the edges gave me a rough folded bracket. A quick file of the edges and work-over with some fine emery removed all the tool marks… quickly followed up with a coat of etch prime to protect it.
I now had to work out how to mount the plastic housing the bonnet release cables were located in. On the rear of the fitting were two plastic tabs that locked into two square holes punched into the vehicles cross member.
So a few minutes spent with a dremmel and a couple of suitable sized swiss files later…
… and the piece was ready for a final rub over with scotch bright a second coat of etch primer and two coats of black.
All went a bit easy actually… which is flipping’ unusual for me. I released the bonnet (or ‘hood’ for my American friends) cable fitting and simply clipped it back in to the two new holes I’d made.
The Provent was installed next…
… again without any issues. Next was to sort out the plumbing.
I’d done a bit of research and asking around and the guys at ASH… AutoSiliconHose.comhad come highly recommended. So a road trip over the Pennines to Mirfield (just east of Brighouse in West Yorkshire) was scheduled.
I had a basic list of what I thought I’d need and the chap behind the counter hooked me up with everything… including the alloy couplers he cut to size while I waited. Great service from ASH and I can definitely recommend them.
Back home with my shopping, it was time to start on the plumbing.
For securing pipes, I personally prefer spring clips… the type you install with special pillars, however the silicon hose OD was slightly too large for may normal stock of clamps so I had to opt for using the wire type. I’ll order some of the correct size and replace the wire clamps as soon as they arrive.
It was really simple now to just assemble the bits, cutting the silicon pipe to length as required. I used a pair of plastic conduit cutters to easily slice through the pipe.
Before I made the final connections to the crank case breather port or the turbo inlet port I blew the pipes clear using a high pressure air line.
All that was left to do was install the drain hose, one way valve and drain tap. I used normal 20mm oil line for the drain, inserting the one way valve about three inches below the outlet of the Provent catch can. The remainder of the hose was dropped down to chassis level and the drain tap added and secured with a couple of zip ties.
I secured the pipes in a couple of places with zip ties, now I know the route I can make a small stand-off bracket with two rubber lines “P” clips to mount on the engine to hold the pipes, although they are self-supporting because of the short length.
In the photographs above it looks like the piping is tight across the engine, I did do a pull and push test and there is plenty of movement at the 90 degree bends to allow the torque twist of the engine without pulling or pushing on the pipes at the catch can end.
The current mileage is 11,750 or there abouts, so I’ll check the drain and filter in 100 miles and each 100 miles after that so I can get an idea of how the setup is going. I’m not sure how long the filter is designed to last, but Ill put it on the schedule to replace ever main service. The other thing that is an unknown is how much oil I’ll get. I have been watching some YouTube videos made by Berrima Diesel in Australia (if you watch any of the Australian 4 x 4 or off-road channels you will recognise the name). I only found out about their catch can experience when one of the guys from one of the 4 x 4 adventure channels got in touch… even if you don’t think you need a catch can but drive a big diesel their videos are well worth watching.
Ok… I was saying I don’t know how much oil to expect… but it did surprise me that Berrima Diesels posted a video showing a new 4 x 4 with about 6000Km on the clock had produced about 300ml’s of oil using the same Provent catch can. It’s also worth taking look at what the have to say about the current oil specified in diesel engines.
The other thing I noticed was when I left the engine ticking over for about ten minutes. Bearing in mind I had just come back from West Yorkshire via the M62 and M60 and started the pipe install as soon as I got back so the engine was still hot, the difference in temperature between the short length of pipe exiting the crankcase vent and the inlet pipe of the turbo. The pipe exiting the crankcase vent port was almost at the temperature I could not keep my fingers on it, while the inlet pipe I’d connected too was still cool. I’ll have to get my thermomiterbob laser do-hicky out and get some readings… but anything that helps cool gasses going into the turbo has to be of benefit right?
That’s it for now, I know it’s not caravanning related that much… unless you want to get the best out of your diesel while towing. I promise the next one will be caravan related, honest!
As in part one I’d also like to give a shout out to Charles at HumbleMechanic.com for all the information and videos he produces about VW vehicles. Charles has been an absolute gold mine of information for all things VW and if you drive any of VW’s vehicles please be sure to drop in on his YouTube channel and take a look.