Category Archives: Electrical

The problem with information from the internet…

08 Sunday Dec 2019

Posted by in Caravan Electrical Fault Finding, Caravan Electrics, Electrical, Modifications, Motor Home, Technical

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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.

Case 1

“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.

Conclusion

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.

Case 2

“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.

Conclusion

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.

Euro 6 Engines, Smart Alternators and Your Leisure Battery…

27 Saturday Jul 2019

Posted by in Caravan Electrics, Electrical, Technical, tow vehicle, Uncategorized

≈ 28 Comments

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About 12 months ago I wrote a blog post “Is A Euro 6 Engine Killing Your Leisure Battery?” and it got a few comments and generated a number of emails. However 12 months on I’m getting a lot more questions relating to problems around smart alternators and I’ve brought forward this blog post by quite a few months from my planned posting date following a couple of long email exchanges with two readers and a few others.

Right, I think the best way to explain this is to set the stage so to speak.

Bob stores his brand new caravan at home and it is regularly plugged in to the house to run the internal battery charger and a dehumidifier. It’s got a new 110Ah AGM leisure battery and a new motor-mover fitted. The caravan is plugged in at least 24 hours before any trip to get the fridge down to temp prior to stocking it up. Bob also has a brand new car, Euro 6 diesel with a smart alternator. The car is a few months younger than the caravan and he’s never towed a caravan with this car. The tow bar and tow electrics were all fitted by the dealer (or dealers agents) prior to it being purchased. He did tow this caravan on 4 trips with his previous car, same make but 6 years older.

The caravan suitably prepped, fridge down to temperature and stocked. An early morning departure and six hour journey with a couple of stops to catch the Euro Shuttle over to France followed by a couple of hours driving in France to their first destination. On arriving, Bob sited the caravan on to the pitch not using the motor-mover and went about setting up. Mrs Bob knowing a request for a cup of tea was imminent went inside to put the kettle on where she discovered everything in the freezer had defrosted. Bob checked the fridge, it was still set for travelling. For what ever reason he also checked the leisure battery on the caravan’s system… 12.1 volts.

Over the next few days there was a couple of phone calls to their caravan dealer along with a number of emails. For the next three weeks and 2 other camp sites the fridge worked perfectly. On the return trip a similar distance and travelling time to the outward journey ended up when Bob returned home he only managed to get the caravan part way up the drive using the motor mover. He had to plug the caravan into his house overnight to charge the leisure battery enough to allow him to use the motor mover to finally put the caravan into its ‘home’ at the rear of the house.

Within a couple of weeks the caravan was returned to the dealer for extensive checking and the dealer could not find any issues with it or the fridge. They put forward the idea it must be an issue with the car. Bob tended to agree with this as he had taken this caravan on four trips towing with is old car and never had any issues. Three relatively short trips, the other a longer two week trip from the North East down to Cornwall, a similar 8 or 9 hour journey and everything seemed fine.

After a conversation with the main dealer who agreed to have the vehicle towing electrics checked over the next couple of days. The verdict from the main dealer was they could find nothing wrong with the vehicle, everything was working as expected.

Now, this is where I got involved. The above is actually an amalgamation of two very similar emails asking for thoughts and advice. The people involved had vehicles from different manufacturers and the caravans were also from different manufacturers. The only common element was the vehicles were new and had Euro 6 engines with smart alternators. I am not going to mention the vehicle or caravan manufacturers for a couple of reasons…. one, I don’t want to end up on the wrong end of a legal letter and two, I don’t actually think the manufacturer of either is relevant.

What’s Going On?

Luckily for me Bob is recently retired but knows his way round an AVO 8 being an apprentice TV repair man for Redifusion back in the day when valves were king. (Just as an aside, I bought my first AVO 8 back in 1976 and paid £8 for it. It was Ex REME in a leather case. I purchased it from MAZEL RADIO on London Rd in Manchester. Anyone from Manchester of a certain age will know Mazel Radio).

To cut a long story short over a period of a couple of weeks we proved that when hitched up, as soon as the smart alternator went into eco mode, there was a current flow up to about 4.5 to 5 amps FROM the leisure battery TO the car. This only stopped and reversed when the electrical load in the car caused the vehicles ECU to turn on the alternator’s output. Furthermore we determined that with the caravan hitched up, the period the alternator was in eco mode was also longer than when unhitched. Although we could not prove this with definitive evidence, this would also support the reverse current flow from the caravan to the vehicle that we were seeing as the caravan leisure battery was now supporting the vehicle battery.

Now there were a few questions that were buzzing round my brain….

  • Why didn’t the caravan habitation relay drop out when the smart alternator went into eco mode to stop this reverse flow?
  • Why didn’t the dedicated tow electrics strop this reverse flow?
  • Why didn’t the vehicle ECU knowing a trailer was hitched stop the alternator going into ECO mode?
  • If the ECU put the alternator into eco mode why didn’t it drop the fridge supply and by default release the habitation relay?
  • Why did the fridge defrost/not work even though in theory there was a voltage supplied to it?
  • Was this the reason I had seen an increase in emails relating to motor mover issues and batteries not holding their charge?

What Next?

I don’t really know. I don’t know how wide spread an issue it is or its going to become. I also don’t know the details of how specific manufacturers implement eco modes in the ECU programming or how the tow bar electrical interface manufacturers could work round the potential issues while still being able to get their products certified by vehicle manufacturers.

I think it might be down to the caravan manufacturers to come up with a solution. I know that there are a couple of after-market products available that provide a solution – We have one I installed in our caravan and in the short term I think this will be the quickest route. Caravan manufacturers may have a reluctance to respond and they can legitimately say “Well it is designed to work correctly to the relevant standards.” I think that maybe it will require the two main caravan clubs to look further into this and if what I have outlined above is proven by them to be the case, bring pressure to bear on all the parties concerned to come up with a way forward to resolve the issue.

For my part, I have contacted a few manufacturers asking for information and clarification or even acknowledgement of an issue. Unfortunately no one seems to want to talk about it. I do know individuals have emails details of their own problem to manufacturers and have received less than helpful responses.

Let me know in the comments below if you have had anything that might be related to this. I’d like to find out more.

EDIT:…

The thought just crossed my mind…. what affect, if any, will this have on AL-KO ATC (if fitted) when the vehicle is in eco mode and the alternator shut down? Does is mean that there is a possibility that the AK-KO ATC may not work correctly in all circumstances?

Overland Vehicle Electrics and Other Stuff…

17 Wednesday Apr 2019

Posted by in Caravan Electrics, Electrical, Help Guides, Maintenance, Modifications, Uncategorized

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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…

Question 1

“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?”

Auto Switch Driving Lights

Link to A3 PDF – Auto Switch Driving Lights

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!!!

Question 2

“Whats the best layout for connecting a solar controller / inverter / isolation switch to my battery bank?”

Overlander Wiring Diagram - 01

Link to A3 PDF – Overlander Wiring Diagram – 01

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.

Question 3

“What’s the basic layout of the vehicle fridge and leisure battery charing circuit?

Basic 13 Pin Power Loom 1

Link to A3 PDF – Basic 13 Pin Power Loom 1

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.

Something For Your Toolbox…

03 Wednesday Apr 2019

Posted by in Caravan Electrical Fault Finding, Caravan Electrics, Caravan Fault Finding, Electrical, Maintenance, Technical

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A few weeks ago I posted a blog post called “A Quick Fault Finding Tip…” and that  generated quite a few emails regarding electrical testing and how to trace faults.  In fact a lot of the other electrical posts I’ve done over the years still generate emails and comments (it’s always worth checkingback on some of th eolder posts to read the comments) I’m going to try to explain a technique that’s really handy to have in your tool box for general fault-finding.

Earth Side Testing

Most people who perform general maintenance on their vehicle, motor home or caravan will be familiar with checking the voltage of the vehicle or leisure battery using a multimeter. Great little things to have and personally I think everyone should be able to do the basics with one.  So as a bit of a refresher I’ll go through this scenario with you. Checking the lights on your tow vehicle you notice one of the brake lights is a lot dimmer than the other. Let’s find out why. I’m going to simplify the circuit a bit it should give you the idea behind the principle.

Depending on the device you re reading this on the drawings might be small. If you want to see the drawing full size just click on it to open it up full size.

Earth Side Testing 1-0

In the drawing above you can see the basic circuit. The positive lead from the battery goes through the ignition switch and on to a fuse. From there through a connector to the brake pedal switch and on to another wiring loom connector to the back of the vehicle. It passes through another connector before arriving at the brake bulb holder. The holder is connected to the vehicle chassis via another wiring loom connector. The vehicle chassis is connected back to the battery in the engine bay. You can see we’ve checked the battery voltage with out meter and it reads 12.68 volts… so not a flat battery. We’ll make a note of the battery voltage.

OK… so the problem is this bulb  is not at full brightness.. so it’s got to be a loss of voltage supplying it somewhere in the circuit. We need to check the voltage along the circuit with the bulb lit (circuit live) and the black negative lead of our multimeter attached the battery negative terminal. (I’ll explain how to do this later).

Earth Side Testing 1-1

Probably the next place to check it would be the fuse… 12.66 volts, not too bad only 0.02 or 20 mV loss… lets keep going….

Earth Side Testing 1-2

..next is a wiring loom connector, back probing it gives a 10 Mv drop (loss) normally these modern connectors are pretty good.

Earth Side Testing 1-3

Brake light switch… Hmm a bit more of a drop… maybe a quick spritz with contact cleaner will sort that…

Earth Side Testing 1-4

Back probing the next connector gives a bit more of a loss… I’ll come back and check the brake light switch connector.

Earth Side Testing 1-5

OK, now at the back of the vehicle and a bit more of a drop at that connector but nothing too much…

Earth Side Testing 1-6

Well 12.13 volts on the bulb contact… so between the battery and bulb positive tip a total loss of 0.55 V or 550 mV…. that’s about within limits as I would not expect to see much more than a 500 mV… half a volt drop on a typical circuit like that. So what’s going on? A 500 mV drop can’t account for the dim bulb?

However, if we keep going and measure the voltage on the earth side of the bulb holder….

Earth Side Testing 1-7

Hang on we see a reading of 2.67 volts. How can that be? We are connected to ground at both ends of the meters test leads? A circuit has two sides, the positive side to the load – in this case the bulb and the return or negative side back to the battery.

Just because the negative wire on the bulb holder is only short and goes to a bolt securing it and maybe many others to the chassis doesn’t mean we can assume it is the same as being clamped to the negative battery terminal.

A few things to ponder…. vehicles are made of steel… steel is not as good conductor of electricity as copper… nether is aluminium that some vehicles have in their construction. At one time steel panels were all spot welded together… now a lot are bonded on with specialist adhesives. The earth point may well be in the boot or under the floor and will be subject to corrosion as will the main battery neutral cable in the engine bay. All this can compromise an electrical path back to the battery.

If we look at the voltage drop on both sides of the circuit we have 0.55 volts on the supply added to 2.67 volts on the neutral side…. 3.22 volts in total, so we are trying to light our bulb with only 9.46 volts.

Could we have got there quicker?

One of the checks I always do first with the ignition on is the battery voltage check to get a reference to work with and then simply move my red positive test lead over to some main point on the engine block….

Earth Side Testing 1-8

If I get a reading of more than 0.4 volts (400 mV) obviously my negative return path from the vehicle chassis is compromised. Time to turn everything off and undo the main earth cables to the chassis and engine and give them and the mounting points a good clean with scotch bright or fine emery and a dab of specialist grease (see “Shopping” below) to protect them from further corrosion.

In the scenario we have just gone through, I’ll bet a wet weekend in Blackpool that cleaning both the earth terminal at the back of the vehicle and the battery earth to the chassis would have sorted the problem. I’d also have a look at the brake pedal switch as there is a bit more of a voltage drop than I’d like. Most likely it’s the connector rather than the switch itself.

For those that tow…

Nearly all tow bar wiring looms will ground to the same point in the back of the vehicle with some of the other assorted vehicle earth cables…. installers take the easy route and if there are already cables earthed there … then another couple won’t make a difference.

This can and will have an effect on the performance of your caravan electrics. Both the leisure battery charging circuit and fridge circuit will probably be earthed at that point.. So in the case of the fault above, each of those circuits will have a voltage drop of 2.67 volts. Therefore if you have leisure battery charing or fridge issues its possibly not the wiring in the caravan,  it could be the wiring in the vehicle. Check the ground path first.

One quick check is with lights and ignition turned on, do a volt drop test between the battery negative terminal and one of the cable secured under the earth point at the rear of the vehicle where the tow pack electrics are terminated. If it’s above 0.5 V (500 mV) then give the earth points a clean.

One bit of advice I’ve given to people in the past is to run a 4mm or 6mm cable directly from the negative battery terminal to the back of the vehicle and terminate it at the earth point where all the rear lights and tow electrics terminate. Makes a heck of a difference.

Back Probing…

Frankie-Howerd

Right…. Franky Howard fans stop it now! Back Probing, you might have heard of it and really it’s nothing special. It’s a simple technique used when fault-finding and involves using a fine probe to get into the back of the connector where the cable enters to test the voltage without disconnecting the connector. Sometimes you can get away with a straightened paperclip wound round the tip of the multimeter test lead. You can buy test lead accessory packs that have various attachments or ‘caps’ that fit on the end of your test leads to make the task easier.

Screenshot 2019-04-03 at 11.11.25

How do I test between the battery and some other point on the vehicle or caravan?

I have made a few of these over the years… basically it’s a long length of wire, about 20 feet with a battery terminal sized crocodile clip at one end and a small crocodile clip at the other… and I don’t know how many I’ve given away to people. I have a couple, one long enough to get tot he back of the vehicle and one long enough to get to the back of the caravan when its hooked up to the vehicle. SImply clip one end to the battery negative terminal and the other to the negative lead on your multimeter. Often its an idea to tie a loose knot in the two leads to stop them coming apart. Caution though, this lead is connected to the ground side of the battery – don’t let it dangle where it might touch something… put a bit of tape for protection around the connection if required.

Shopping…

Multimeters…. a person can never have enough multimeters…. and since the demise of Maplin a couple of great places to keep an eye on is Aldi and Lidl. I got a couple of great general purpose multimeters from Aldi for £9 each. Not always available as they generally come up as special buy’s. However if you are an Amazon shopper then this https://amzn.to/2I91q91 seems like a great little multimeter with a lot of positive reviews for £12

I use Liqui Moli 3140 Battery Clamp Grease – https://amzn.to/2Vn0qSo for battery and chassis terminals. It’s a small tube but does last a while.

If you want to make your own long test lead this box of crocodile clips https://amzn.to/2VedU32 for about £4.50 is always handy.

A dream test tool…

If you are into testing or it’s part of your job then there has been something on the market for a while called “Power Probe” Now while the original is obscenely expensive and there are a number of copies out there. The Auto Power scan PS100 is priced at about £80 and does the job in one simple instrument – https://amzn.to/2OJHYAW (Any sponsors out there… hello….hello…) This is on my “I really want one of those” list!

Finally…

"Oscar" our senior safety cat.

As always when working on anything electrical think safety. Oscar our Health & Safety Cat would like to remind you that working on vehicle electrics can be just as dangerous as working on house electrics. If you are unsure then DON’T…. get in touch with someone who is qualified. Find the right person and they will usually help you to do it safely. Be like Oscar – Be Safe.

A Request…

09 Sunday Dec 2018

Posted by in Blog updates, Caravan Electrical Fault Finding, Caravan Electrics, Caravan Fault Finding, Caravan Servicing, Electrical, General, Help Guides, Maintenance, Motor Home, Technical

≈ 11 Comments

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Ok, not one of my usual blog posts. I get a lot of email asking about various electrical items related to caravans and motorhomes and a few things seem to keep cropping up on a regular basis. One is to do with 12 volt relays… what types are there and what are the pin connections.

Another is to do with cable size relating to load and its relation to the length of cable…. “I have a 40 Amp load and its 3 metres from the battery… what size cable do I need?” type questions.

In the past I’ve emailed back with answers, but one caravan engineer asked me if I know of any information sheets that had this type of info that he could put above his workbench.

So I’ve produced a couple of A3 size PDF information sheets (they will print A4) that can be downloaded printed out and pinned up, shoved in your notebook, glued to the lid of your tool box or used to wrap that must have tool present for your beloved caravan or motorhome DIY enthusiast in your life (seasonal eh!)

(I have been told that Office World can print and laminate A3 PDF’s cheaply…. I never knew that!)

Screenshot 2018-12-09 at 10.23.41

Click here to download the  Relay Wall Chart

Screenshot 2018-12-09 at 10.24.11

Click here to download the   Wire Size Wall Chart

Screenshot 2018-10-11 at 16.52.54

Click here to download the Fuse Voltage Drop Table

I have stylised them as technical drawings and I’ve had to watermark them and some of the icons as I found a lot of my drawings were ending up “as is” or edited on various sites and forums without any credit or link back to Caravan Chronicles. You are free to print out and use them for your own personal use, but if you wish to use them (or any of my drawings) for commercial use, inclusion in blog posts or forums please include a credit line back to CaravanChronicles.com and drop me a line to let me know.

We are just back from Chester Fairoaks after doing the Chester Christmas market and a bit of shopping at Cheshire Oaks Designer Outlet Village and will be adding off to York for a bit more Christmas Market action.

I have a couple of more information ‘posters’ in development but if you have any ideas for future offerings, drop a line in the comments below. Of course my legal advisor – Henry has asked me to point out E & OE

(Everything on the internet is improved by a cat apparently… so here’s Henry)

IMG_2176

A Quick Fault Finding Tip…

12 Friday Oct 2018

Posted by in Caravan Electrical Fault Finding, Caravan Electrics, Caravan Fault Finding, Caravan Servicing, Electrical, Technical, Tips

≈ 16 Comments

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Sometimes things you take for granted and have in your toolbox of fault-finding tricks are a dark art to others.

I was talking someone through a bit of fault-finding on their vehicle and asked if they had measured the current in the circuit. “No” came back the answer. I asked what type of fuse and rating it was and asked the person to just put their voltmeter across the fuse and tell me the voltage across the fuse. “Ah… that’s about 3.2 amps then” I said.

“How do you know that?”

Simple really – all fuses have a resistance and if you know that you can work out the current from the voltage drop. Even simpler really – there are tables for various fuses that have it all worked out for you. I have a selection collected over the years stuffed into the lid of my tool box, along with a lot of other junk paperwork!

I created a volt drop table based on PEC (Pacific Engineering Corporation) fuses that are supplied as OEM fuses in most Japanese, Korean and European vehicles however it is pretty accurate for almost all other makes of the same type of fuse. I printed mine out, laminated them and added them to the collection in the top of my toolbox.

Screenshot 2018-10-11 at 16.52.54

It’s quite easy to use. Just set your multimeter to read DC mV and read the voltage displayed. Now select the fuse type, in this case an ATO fuse – the most common used in vehicles, caravans and motorhomes and from the chart look down the left column until you see the voltage measurement that matches the one on your multimeter… lets say 0.011 volts (11mV)

The fuse is a red 10 Amp fuse so follow the 0.011 volt line across until you get to the 10 Amp fuse column and read the current figure… in this case 1.3547 or 1.3 Amps. It’s as easy as that, no need to break the circuit to put your multimeter in as an Ammeter.

fuse-buddy-specialty-meters-esi305m-64_1000
I have a couple of these cheap handy plug-in ammeter’s…  although they do have limitations and only work up to 20 Amps.

Although the table is based on PEC ATO/ATC and MINI fuses (download info below) it is pretty close with most manufacturers fuses and as a general reference for fault-finding will be good enough to 0.1 amp.

If you need to know the actual current through a circuit, you need to use an ammeter and not rely on tables but for general work they are close enough.

These tables also come in handy if you are trying to find out why a battery is draining. Without turning anything on it is easy to run through a fusebox checking to see if any circuits have a current drain on them without having to constantly pull fuses and insert an ammeter, which sometimes can upset or reset the circuit you are working on.

One thing to remember with this test if you’re tracing a fault, is you are only measuring the volt drop across the fuse to determine current. You really need to know how much current you should be drawing. For example, If I was testing the 12 volt fridge circuit fuse and I only got a voltage drop across the fuse that calculates to 6 Amps then I’d know there was an issue somewhere along the circuit as I’d be expecting around 10 Amps or more.

A word from our Safety Officer…

"Oscar" our senior safety cat.

Oscar would like to remind you that working on a live circuit has risks and never attempt to undertake volt drop measurements on mains circuits. Most cheap multimeters do not have the internal protection or fused test leads. Be safe. Be like Oscar.

You can down load the table in PDF format (4 pages) and either print them out or save them to your device from the following link: Fuse Voltage Drop Table

Unfortunately due to a lot of my drawings and text being used elsewhere without credit back to CaravanChronicles.com  I’ve had to start putting watermarks on a lot of things. I hope this doesn’t make the table too difficult to read.

P.S. Someone told me that everything on the internet can be improved by cats and my “likes” would go through the roof!

E-Trailer….Smart or what!

28 Monday May 2018

Posted by in Accessories, Electrical, Gadgets, General, Maintenance, Modifications, Uncategorized

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A few weeks ago Andy Harris (yes that Andy… him off the TV) and of Road Pro fame called me to tell me about a new gadget that Dutch caravanners were getting all excited about. Now not one to turn down the chance to test a gadget or two, when Andy asked if I’d like one of the units to test I of course said in true reserved fashion said “Well I suppose I can take a look at it”. Who wouldn’t pass the chance to check out the latest piece of tech gadgetry being made by those clever Dutch people at e-Trailer. A few days later a large brown box arrived.

On a recent trip to the C & M Club’s site at Blackshaw Moore I took the opportunity to not only put my feet up for a couple of days with Sue but install and play around… er… seriously test… one of the units..

Blackshaw Moor C & M Club

Opening up the box I found five smaller boxes, containing the main unit and four of the modules.

IMG_1400

Ok, so what is e-Trailer? The simple explanation is there is a black box that sends all kinds of information about your caravan to an app on your phone. It works with both Android and iPhones and there are various ‘modules’ you can add-on to get additional info.

IMG_1403The actual unit is about 120mm long by 80mm wide and 40mm high with a good quality power connector at one end.

In the box is the main unit, 1.5 metre long power lead, instruction manual and a card with a QR Code on it.

You get a QR code with each of the modules, and set of instructions, don’t lose the cars with the QR codes on them! (more about these later)

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Installing the unit is serious easy. You just hook up the power lead to a 12 volt supply. I opted to connected to a switched supply sort came on whenever the caravan master switch was on. This would mean it would be active when towing.

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Once you have powered up the main unit, go to the website e-trailer.nl/app and follow the link for your phone. In the case of my iPhone it took me to the App Store were I could download the app. Once downloaded launch the app and follow the on-screen instructions to register. I was a bit surprised it asked for my postcode and house number, but I guess this is how they register the unit to you for warranty etc.

Once you have created your account in the app and logged in… well remember that card with the QR code on it, simply scan the code and it pairs the app with the unit you have just installed.IMG_0861

You are done! It’s that easy. Now to add the modules. The first one I added was the temperature module. You get a small puck shaped device and following the on-screen prompt, scanned the QR code.

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Done… a quick scan and now I have the temperature reading. For each module you can set lower and upper limits and the type of alarm… visual notification, vibrate, sound. From reading the instructions you could put this sensor in the fridge so when you are driving along you can keep an eye on the fridge temperature to make sure your wine or beer is perfectly chilled when you arrive. From what I understand you can add additional temperature sensors so you can check what the temperature is in the caravan at the same time.

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Next was the voltage sensor so you can keep an eye on the battery voltage. Again it was a quick scan of the QR code and I could see instantly what the battery voltage is and its relative state of charge. (I have yet to check how accurate this is).

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Again, it is easy to set the limits, just tap the two cogs in the bottom left corner….

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… And you can adjust the upper and lower alarm voltages. This is really useful as you can correctly set it for flooded call, AGM or lithium batteries.

Want to know if you have left your roof light open or TV aerial up… or even if your fridge door is open? There’s a module for that… The E Switch.

IMG_1409

In the E-switch module you get two magnetic contact switches that come with 3M pads so you can stick them almost anywhere. Again adding them is a simple scan of the QR code and follow the instructions on-screen. I edited the text for the first switch so I know it is the TV Aerial.

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If one of the switches is open, on the home screen you see that the padlock is orange, close the switch and the padlock closes and the icon turns green.

So what else can it do? Well I also have the tyre pressure monitor module. You get two pressure sensors to attach to the tyre valve stems. The sensors are the type that you can change the battery, which I much prefer, as opposed to the sealed type. I’ve not installed the TPMS module yet as I’m still testing out other TPMS systems on the Amarok and caravan but no doubt it will be an easy install… by just scanning the QR code!

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The last little trick that is has is it is an extreme accurate caravan levelling aid. Again a quick scan of the QR code gets this up and running and follow the on-screen instructions to determine your level point and it becomes easy to level next time you pitch.

OK so what did I think about it?

Well it was super easy to install. It was also super easy to add each module. I like the fact that when you hit up to set off you can check the battery voltage and see if it is charging. You can make sure what ever you have attached the magnetic contacts to you can see if they are in the correct position (i.e. closed, lowered etc.) and you can check the fridge or caravan temperature and tyre pressure.

While driving you can keep an eye on things like your caravan’s tyres, battery charge and fridge temperature. when you arrive on site, reversing into your pitch you can easily see if the caravan needs levelling side to side using ramps or blocks and when you un-hitch you can adjust the jockey wheel to get perfect levelling front to back.

“We have a problem Huston…..”

Now I do have a problem with it. Come what may I cannot get it to vibrate, notify me or play a sound when  anything goes out of the parameters (switch open, battery voltage low etc. I made sure I had the latest version of the app, I have double checked all the settings within my iPhone but I cannot get a single ‘vurrrrrr’ or ‘ding’ out of it. Admittedly my iPhone is now 2 versions behind the times but if the app installed I’d have expected it to work ok. I’ll continue to work on this one.

Finally…

I think the idea and technology is great behind the product and I really do like it and can see lots of additional applications could be added on in the future.

Why though is it an after market accessory? When you can be paying the best part of £30k for a top end caravan should not this sort of information system be standard? When I hitch up and set off, I’d love to be able to check the battery voltage (and charging current) check the fridge was working, tyre pressures, doors and hatches closed… and it is not beyond the engineering skills of man to be able to have a bulb out detection system for the road lights even…. all fed directly to your phone.

If a manufacturer decided to install such a unit the price point would drop dramatically.. and that’s one of my other niggles. The technology and ease of installation is great, however there is a bit of an ‘ouch’ in the wallet as currently the comfort pack is priced around £380. That’s a lot of nights on site. You can build up the unit by just buying the individual modules though.

Do I want one… “Yes”…. would I buy one…. I’ll just go and have a word with Sue.

The e-Trailer is currently available from Road Pro here.. www.roadpro.co.uk/catalogue/01m-smart-trailer

Getting All Charged Up – Update 2…

29 Monday Jan 2018

Posted by in Accessories, Blog updates, Electrical, Gadgets, Maintenance, Modifications, Product Review

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I guess this really is the update to an update (Getting All Charged Up – Update…). We have been living with the Sterling Wildside unit now for about 6 months and a LOT of people have been emailing me asking how we are getting on with it and is it worth it?

IMG_1194Well I have done quite a bit of testing with my leisure battery in various states of discharge. With it at about 50% I have recorded a charging current of 15.9 Amps which is far greater than I could manage before and due to the fact that the Wildside unit uses the correct charging profile for my battery I’m not concerned that I will be reducing or damaging my leisure batteries life expectancy.

Earlier this month I had an email from David Dent who had successfully installed a Wildside unit in his Bailey Unicorn 3 Cadiz and he seemed pleased with the results so far. Although installing it in a Bailey was a bit more of a challenge. I’m looking forward to checking back with David to see how he is getting on with his unit.

A couple of other people have also emailed me reporting that after installing a Wildside unit that it had solved their problem of having enough stored energy to operate their motor movers. I still wonder if people who have been experiencing problems with their motor movers caused by supposedly bad batteries and have had to replace them is possibly down to the fact their battery was never really receiving a correct or full charge before causing its early demise.

New Tool…

One of the things I want to get to add to my ‘tool box’ in the near future is one of the computerised digital battery testers. At the moment I’m basing a lot of my work on the voltage of the battery and chemistry type. I’d like to be able to improve on this.

Watch This Space…

The other thing I’d also like to be able to do is get a voltage and charge current reading for the leisure battery while we are actually driving. I have been looking at a few – mainly American options for bluetooth remote voltage and current sensors that you can connect up to with your phone. There are a couple of devices that offer a separate display to fit in your vehicle.

However, there is a rather exciting unit that will shortly be coming on the market in this area that might be a bit of a game changer. If you want to know what it is well go and see Andy Harris or one of the guys on the Road Pro stand at the NEC in a couple of weeks time as they, along with the manufacturer will be launching and demonstrating a new product that might just be bringing caravan technology bang up-to-date. I hope to be bringing you a bit more about this soon and maybe an install too!

Final Thoughts….

Is the Wildside unit worth it?  Before I answer this let me just say I am not being paid by anyone for any endorsements of this unit. I was supplied one of the first (pre production?) units as a test and to provide feedback to Sterling Power on how easy it was to install and it’s performance in the real world, which I did. As a result a couple of things were ‘tweaked’ hence mine had to be returned, reprogrammed and reinstalled.

Well I’d say if you have a Euro 6 or even a 5 engine and you want to make sure your battery is looked after then yes. If you want to upgrade to a more advanced battery chemistry, again yes.  If I had to return mine would I go out and buy one? Yes I would.

Is there anything I’d like to see changed? Well if they ever did a Wildside 2.0 I’d like to be able to move the caravan’s own charging system so it was routed through the Wildside unit when on mains hook up to take advantage of the Wildside’s smart charging facility and to allow you to move to more advanced battery chemistry. I guess also adding a solar panel input with built-in MPPT would be a big hit too.

In The Future…

I’m starting to wonder if the way we charge and power caravans needs to take a leap forward. I have had an idea that you could basically split an inverter. One half in the vehicle and the other in the caravan. Imagine a small unit that takes the 12 volt DC from the vehicle and inverts it to 48 volts AC. You then have a lead that connects this across to the caravan and there it is converted back into 12 volts DC.

So whats the difference… all you are doing is what’s already happening? Well using a 2.5 mm cable rated for 25 amps at 48 volts gives you 1200 watts of power. To transfer that much power at 12 volts you would need 100 Amps. Keeping it at 48 volts will mean the system is still in the ELV range for safety. (Use 4mm cable and this could be 1680 watts of power which would be equivalent to 140 Amps at 12 volts)

Being able to transfer that sort of energy would allow you to forget LPG cylinders and put 1000 Ah of lithium cells in the caravan with a 240 volt inverter and power everything. Just a thought that I’m throwing out there.

Is A Euro 6 Engine Killing Your Leisure Battery?…

21 Friday Jul 2017

Posted by in Accessories, Amarok, Caravan Electrical Fault Finding, Caravan Electrics, Electrical, Maintenance, Modifications, Off Grid, Technical, tow vehicle, VW Amarok

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OK… so that title was a bit dramatic! However here’s the thing… I don’t think everything is peachy with Euro 6 engines and charging leisure batteries.

If you are a regular reader, you know I have recently installed one of Sterling Power’s Wildside units (and so far I’m super happy with it!) but I did get an email from someone who had read all my postings about it and asked me if it might cure his problem. Here’s the gist of his email….

Note: I have edited this down a bit…. and withheld the name of the person and vehicle.

“I have recently changed my car to a new 2017 xxxxxxxxxxxx and after several trips with it, on arriving home there is never enough charge in the motor mover to manoeuvre our caravan up our drive (which is on an incline) and park the caravan round the back of the garage. I have to plug the caravan in overnight before I can use the mover.

This only seems to have started happening since we changed to the xxxxxxxxxx. I had the caravan’s battery tested at two garages and they said it is OK and it is only 2 years old. The local caravan service man said he could not find anything wrong with the motor mover.

As we are on mains at the caravan sites we visit for a few days the caravan battery should be fully charged.

Can you help?”

This did have me stumped for a bit. Battery tested OK, no issues with the mover, so what was going on?

While doing some of the prep work for writing about my installation of the Wildside unit, I had spent a few days prodding about our VW Amarok with a multimeter and making a few notes about voltages etc. One thing that I did cotton on to was the cyclic way the vehicles ECU seemed to turn off the alternator…. well I should really say put the alternator into “idle” mode. Now with the caravan attached (pre Wildside unit install) I did notice that  at the start it seemed to take longer for the vehicle’s alternator to go into idle mode but also it seemed to stay in idle for a lot longer and I was in the process of trying to work out why as initially I’d have thought it would have been less as it was running the fridge and charging the leisure battery.

A picture is worth… you know the rest. Here’s one of my excellent drawings!

Euro 6 Problem 01

Right, here we go… The drawing shows a caravan plugged into a tow vehicle that has the engine-turned off. Pin 9 is live as it should be, and the habitation relay in the caravan is effectively off allowing the caravan’s leisure battery to connect and power the caravan’s internal 12 volt systems. As the vehicle engine is off, there is no power on Pin 10 the fridge circuit, as this is controlled by the vehicle’s ECU.

Really this could be any vehicle with any engine. Now let’s have a look at what happens with the engine running…

Euro 6 Problem 02

Pin 10 is live, turned on by the vehicles ECU and this powers the caravans fridge. It also operates the caravan’s habitation relay which now disconnects the leisure battery from the caravan’s 12 volt systems and connects it to Pin 10 so that the vehicle can start to charge it.

Again, this could be any vehicle with any engine. This is how our Land Rover Freelander works with our caravan. All straight forward.

Now lets look at what happens when the Euro 6 engine puts the alternator into “idle” (or Eco mode etc.)

Euro 6 Problem 03

This is where it starts to get interesting. I have taken a few liberties here and made a few assumptions. I have shown the vehicle’s alternator disconnected. In practice the ECU doesn’t disconnect the alternator, it will reduce the field voltage and hence the output, not really disconnecting it but reducing the output to a negligible amount.

The ECU will also monitor the vehicle’s battery voltage and continue to allow the vehicles general electrical system to drain the battery to somewhere around 75% charge (this may be a bit of an arbitrary figure) The ECU will then turn on (or up) the alternators output to recharge the vehicle’s battery to about 80%. Why 80% well it needs the remaining 20% ‘free capacity’ so that when you brake, the excess energy of engine braking (regen) can be dissipated into the vehicle battery. Remember that on a Euro 6 engine the alternator is capable of generating round about 2Kw.

Now at this point it dawned on me that something could be happening here, but the idea was a bit ridiculous…. guys with far more agile grey cells than mine must have worked this out and I dismissed the idea. I must have missed a trick somewhere.

I did a bit more checking. I was using two 17Ah sealed lead acid batteries as my “leisure” battery simply because it was quicker to charge or discharge them than a 120Ah battery. For a fridge load I was using 3 x 50 watt light bulbs and it was all jury rigged to a 13 pin plug so I could just plug it in to either the Freelander or the Amarok to make comparisons. I was using a trusty old AVO 8 meter, a couple of digital multimeters and a clamp meter to measure current so really the whole set up was super sketchy for anything that I could write about. I thought that I must have been missing something somewhere and I actually kind of put it to the back of my mind. I just got on with installing the Wildside unit and writing it up.

“DING” You have mail……

I received an email from Charles Sterling with some very interesting information. During testing he had come across exactly the same issue I was pondering over but had put off further testing. I guess by now you have worked it out. Quite simply you can get current flow in the opposite direction… from caravan leisure battery to vehicle battery. In testing Charles had measured a current of around 6 Amps.

It dawned on me that maybe during my initial testing with my jury rigged set up I hadn’t missed something and the readings I had seen were correct. Both Charles and I quite separately had (in my case ‘stumbled’) on a potential issue with Euro 6 engines and caravans.

Back to the original email earlier. It now made sense. The sender of the email was setting off from their campsite to travel home with a fully charged battery (being on EHU while they were on site) and during the course of the drive home, the vehicles ECU was actually reducing the fully charged leisure battery down to 80% charge as it actually thought that the ‘vehicle’ battery was at 100% charge. Hence when he arrived home, the caravan’s leisure battery didn’t have enough charge to run the motor mover long enough to put the caravan away.

So what does this mean in practice?

Well effectively (give or take a bit of loss due to cabling) the caravan’s leisure battery will only get charged to about 80%. You can now think of the vehicle battery and caravan leisure battery as being one battery bank because that is how the vehicle sees it. If the leisure battery is fully charged its voltage will be higher than the vehicle battery so the vehicle will turn off (or down) the alternator so that the vehicles electrical system can drain it to about 75% ready for accepting the excess energy from regen braking. The caravan’s fridge helps the vehicle by draining the battery bank that bit quicker.

This also answers another question. While I was testing, sometimes I’d plug-in my jury rigged setup and if my two little 17Ah batteries were fully charged I’d get a low current drain indicated on my clamp meter. I’d dismissed this to a certain extent, but now I realise that as my two 17Ah batteries were fully charged and the vehicle battery would be at about 80% charge, there would be enough of a voltage difference for a short while, that the two 17Ah batteries would try to equalise with the vehicle battery by recharging it slightly..

Whats the answer?

Well thankfully I solved my problem when I installed the Wildside unit a few weeks ago.

Finally…

If you have had any electrical issues with a Euro 6 engine and towing please drop a comment below. I’ll try to help.

As an aside, I am trying to arrange attending a tow bar installers electrical course with a couple of the OEM electrical equipment manufacturers and one of the approved bodies so I can hopefully increase my knowledge base and widen the number of vehicles I can cover. It’s a bit up-in-the-air at the moment as it would appear its going to cost a small fortune! (Sponsorship deals gratefully received!)