Charging caravan battery

You dont need a dc charger - just run a fused very heavy duty cable from the cars battery positive terminal to the back of the car with a andersen plug at the rear.

The alternator will charge both batteries fine, just like it also can charge an aux battery. Is very basic but works.

Been doing it this way for years to power the trailer when driving and charging the trailer battery.

I agree run the minimum 6B&S from the start battery, after a fuse, to the 50 amp Anderson plugs to the batteries. When connected, check on the batteries SOC. This will indicate if you need a DC2DC charger to bring the caravan batteries to their best SOC.
Your usage of the batteries may require more charge.
Trial and error.

Just to follow up, the Everest does have a smart alternator, which means its charging voltage is lower than conventional alternators. By the time you have a long length of charging cable all the way back to the van batteries, the voltage drop will be significant when the batteries are charging, meaning it is unlikely they will reach 100% SOC even after a long run. (Have a search of Ford Ranger/Everest websites to see the issues people have had trying to charge their batteries when camping!).
The only way to alleviate this issue is to run a DC-DC charger.
I presume OzzieCruiser has not been running a DC-DC charger, since he's been doing it for years?? That would suggest his vehicle has a conventional alternator.
DW Lennox Head has the right idea. If your van batteries aren't getting at least 14V when connected to the car's alternator, then you will need a DC-DC charger.

The voltage offered to the battery in the van determines the rate of charge.
Charging direct from the alternator, the smaller the cable, the greater the voltage drop and the slower the charge, but it will still get to full charge, just slower. If you are consuming power from the van battery while charging, you need to also supply that power in addition to any charge that you want to the battery.
Cheers,
Peter
OKA196 motorhome

No is a smart alternator - if conventional lead acid/agm/deep cycle batteries are used the alternator on start is 14.5 v but once batteries are replenished it drops to 13.5v.

Most people think a Dc Dc charger is needed in all situations but that is not the case -I use a 24v - 12v Dc Dc charger on a 24v vehicle to charge the 12v aux and I would use a Dc Dc charger if using Lithium or some special battery.

But a Dc Dc charger may not be needed in all situations - as was said above try and see how much power (V ) is getting through the the van batteries and take it from there. Make sure you use heavy cable - maybe one size bigger than needed just top be sure.

Even the 14.5V should be OK for charging Li (provided the alternator can handle constant high delivery) and the 13.5V is perfect for Li float.
Cheers,
Peter
OKA196 motorhome

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When using a dc-dc charger that has an 'ignition trigger' function you can avoid the hassle of getting an ignition-source wire to the charger by incorporating a basic 100A solenoid isolator at the car battery. The solenoid coil is connected to the ignition and it switches the battery feed going to the van. Join the charger's 'ignition-controlled' trigger wire to the 12v input line of the charger and thus, when the engine is started, the charger's input line is powered-up and the trigger is activated. Charging begins. 100A solenoids can be had for about $20.

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Peter, you said…."Charging direct from the alternator, the smaller the cable, the greater the voltage drop and the slower the charge, but it will still get to full charge, just slower. "

"Slower" maybe but maybe interminably so.
Consider that, due to circuit resistance, the van battery charge will lag behind the vehicle battery and the vehicle battery's terminal voltage will rise preferentially causing the alternator regulator to reduce charge. The voltage presented to the van battery is hence reduced and together with the inherent voltage drop, significantly extends its charging time. It may never reach full SOC during the drive time.
It all depends on the cable size and hence resistance. As you said….."the smaller the cable " etc..
Skimping on cable size is never sensible.

Will the lovely people at Ford turn off the smart function if you ask them nicely and cross their palm with gold.

Thanks all for feed back .
Bcdc charger v dcdc charger .. whats the difference?
If you have the charger close to the caravan batteries would that change anything i.e like cable size from the car battery or alternator .

Keir I don't know what type of Deep Cycle they are as we are traveling at the moment can look later but definitely won't be going down the lithium battery idea

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Hi Nick,
"dc-dc" charger…… is of course shorthand for a charger with dc input and dc output.
"BCDC"…… Redarc's expression for the same !!! Dunno what "BC" is for sure.

A major advantage of a dc-dc charger is that it overcomes supply under-voltage due to cable losses by boosting the voltage to the correct value for the battery. It does a few other nice things too. Its qualities are only fully realised if installed close to the battery receiving its output in order to ensure that the battery receives the 'proper' voltage without line loss.
You can get away with slightly smaller supply cable.

BCDC=Battery Charger Direct Current

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"Battery Charger" eh? Surely not, couldn't be that simple.

Allan thanks for your help.
When you talk about a 100 amp solenoid I guess you're not talking about a smart switch isolator like the redarc smart start sbi 12v for dual battery application .
That is what I was thinking of putting on the Everest and running a cable to the caravan, would that work and maybe incorporating a DC DC charger in the van .
Also how many amps is this likely to be pumping into the caravan batteries compared to the alternator output

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No Nick, the Redarc SBI12 is a 'solenoid' but operates at more exact control voltage and is un-necessarily complex and expensive than you need for my proposed application. It is only of use if you are charging an auxiliary battery without a dc-dc charger. All you need is one like this.. When the ignition becomes 'on' it engages and sends 12v to the van dc-dc charger. It is useful if you are dealing with a 'smart alternator' as it emulates the "Ignition On" signal to the dc-dc charger's trigger wire.

For vehicles with "Un-smart" alternators none of the above is necessary as you can simply employ a basic dc-dc charger in the van supplied directly from the vehicle battery/alternator.

The solenoid I proposed above is usually installed in basic systems without dc-dc charging where the auxiliary battery is connected directly to the vehicle battery/alternator and requires an isolator to prevent back-feed when the engine is off. I am re-purposing the solenoid to provide an "ignition" signal to the van. It is a simpler way than running an additional ignition wire.

As to your question of Amperage to the van……. The current will vary with circumstances but will be limited to the maximum current rating of the selected dc-dc charger. If you buy a 40A charger then that will be the maximum it can deliver although it will be often at a lower rate as needed.
On the other hand, a system with direct charging from the car without dc-dc charging may deliver higher current at some times but significantly lower current at most times. It is influenced only by the wiring constraints and the output level of the alternator….. often not as you would wish.

Quote - "BCDC=Battery Charger Direct Current"

BCDC is just part of the part numbers allocated by Redarc to their DC-DC charges. They also use it when referring to these items when talking about them. If you look at BCDC Classic Under Bonnet 50A DC Battery Charger , you will see the following text on the page:

"PRODUCT DETAILS
The REDARC BCDC1250D is a 12V, 50A In-vehicle DC to DC Battery Charger designed to keep your auxiliary battery charged when driving or with portable solar panels when parked."

They can be thought of as being power transformers. Traditionally, they were used to transform a lower voltage experienced in some vehicle battery systems to a higher voltage necessary to correctly charge a storage battery (house battery) in a motorhome or caravan. When you transform the voltage to a higher voltage, you also have a higher current in the supply line than you supply to the load (battery.) Power = current X voltage, so if you are changing the voltage in a system the current also changes to maintain the same power input as the output.

When designing a system you must allow for a considerably higher current from the supply than is delivered to the battery. You will also have to factor in a bit of extra input current to power the losses in the charger, allow for at least 5% power loss in the charger. If you are using the cables to supply the charger that are thick enough to have a small voltage drop over their length, I would suggest that you need to design your system to reckon on drawing 25% more current from your alternator than the charger is capable of supplying to the battery.

Allan thanks for the comprehensive reply to my questions appreciated

Also could you offer a amperage size for the charger and the size of cable required from the battery of the car to the DC DC charger in the caravan front boot or Center of van where the batteries are .

question "off topic "if you don't mind .
when camping off grid , the caravan has the Jayco solar panel installed from factory can I add an extra solar system to the batteries for greater charging capacity to the batteries when camping .
Regads nick

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Hi Nick, Easy answers first….. Charger size? : I would recommend 30 to 40Amp capacity as being good whilst noting that of course price rises with Ampere size. And cable size? : You can be persuaded to do calculations but from what you have already indicated I would suggest that when employing a DC-DC charger in the van that a minimum 6B&S or 16mm2 cable from the car to charger and from the charger to battery should be suitable. Best performance is with the charger close to the van battery but if you desire to put the charger in the front boot it would be OK provided that you run a cable of no smaller than 6B&S from the charger output to the van battery so that the charger more accurately senses the battery's voltage.

In making purchasing selection is where it gets more precarious, particularly as you have a variable-voltage alternator. I'll go into the problem a bit for you. I begins with the way your alternator senses the State of Charge of your engine battery which is by means of measuring its voltage. Standard alternators do that too but your variable-voltage alternator changes its criteria according to engine and driving conditions and this will result in your battery having different terminal voltage at different times. And that causes some problems when trying to charge another battery (e.g. on the van) at the same time. It is the reason why a DC-DC charger is recommended. However not all DC-DC chargers cope with the conditions presented to them when being supplied from an alternator/battery combo that is operating in the variable-voltage mode. Consider for a moment how a 'regular' DC-DC charger works when being supplied from a CONSTANT-voltage alternator…….. Firstly, when the engine starts and the alternator is presented with batteries requiring charging, the terminal voltage of the engine battery is elevated by the alternator and the DC-DC charger in the van sees this elevation (>13v) as evidence of availability of a charging source and engages to commence charging of the van battery. As soon as the charge begins, the input terminal voltage drops below 13v due to cable losses but the charger understands this and continues charging even though the input may fall as low as approx. 9volts. Every few minutes the charger will cease charging and seek reassurance that the voltage is still up around 12-13v as evidence that the alternator is still available, then returns to charging the van battery again and this cycle continues.
Now, a system with a variable-voltage alternator presents some problems in trying to use a 'regular' DC-DC charger because when the charger pauses to look for the presence of an alternator it may observe it at a time when the alternator voltage is below the charger expectation and accordingly shuts down the charge cycle. So, DC-DC chargers with an 'ignition-sensing' feature were developed where they rely on seeing an 'ignition' voltage as evidence that the engine is running, as a control signal to activate the charger. They no longer use low input voltage for that purpose and can continue charging with an input voltage typically as low as 9volts. It is imperative that you bear this in mind and select ONLY a charger that has this 'Ignition Sensing' feature. Then choose to run an 'Ignition' wire to the charger or use the "solenoid" system as I earlier suggested.

As for charger brand selection. Suitable 30/40 Amp chargers are available in a price range of $350 for a Redarc BCDC1240D down to a Renogy at $170 but a Kings at $279 could be a good buy. As usual, quality costs more. The advantage of the Redarc BCDC1240D (note the "D" for Dual) is that it has a second input for solar which could be useful for your desire to add additional panels. There is no doubt that Redarc is a superior product but they do cost more.

Nick, I hope this helps you and do come back if you need anything else.

Thanks Alan for the in-depth reply to my questions . my little brain is overheating with all that information to taking lol ..
my initial thought would be a redarc but some of them get very expensive . I must say I was surprised that you would even mention Kings LOL :))
Cheers appreciate your help

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Well Nick, I haven't had any actual hands-on experience with Kings but I keep reading good reports on here and elsewhere, so concluded that the can't be too bad. Do you have better information??

Redarc are certainly good products, both in design and manufacture, but as you say, "Ain't cheap". I selected them for my Troopy but used Enerdrive for the Sprinter as the style suited me better and they are also of high quality. However, Redarc are designed and manufactured in South Australia and you really can't get better than that, can you?…… p.s. I was manufactured in SA also. lol

But $350 for a Redarc BCDC1240D is pretty good. I found that on Ebay. Never buy directly from Redarc.

If your "Brain was overheating" consider how mine was in trying to compose a complex subject simply.
Talking is easier so if you feel a need to, my email address appears in my "Profile" and you could always mail me and I could send my phone number.

Thanks Allan ... $350 is cheap for redarc , prices I've seen is up around $7 /$800 mark . Must be different model . I think you will find a some of redarc stuff is manufactured in china these days , just saying..

The reviews I've seen on youtube of kings solar don't add up to there claims ,

In regards to contacting you ..thanks for that it would be good to drop you a email with a question. I may still have your phone number if you haven't changed it from years ago when you did me a turn when you sent me a gadget

Cheers for now .

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Sorry Nick, I must have memorised it improperly, it is actually $399 and a used unit but that should be OK they do not age with use although you would have no warranty of course.Here is the link.
I found a Victron for $259 but that was only 30A.

And my phone number has not changed. Happy to "do you a turn" anytime.

I have a new Everest with a smart alternator……had it switched off before taking delivery.
Outputs 14+ volts all day long.
Any dealer can do it, even for the older models !

The Ford alt isn't going to reduce to 11.8v because the system, ie, electronics with both petrol and diesel vehicles will ALWAYS be using a few amps to run itself. Just to make high voltage to fire diesel injector via an ECU uses more than you think just to run the engine.

Peter g28.
Explain HOW, if the Everest/Ranger alt fully charges the battery and 14.2 or 14.4 v is achieved, why is it you say, that voltage, maybe with a conventional alt, then endangers the electronic and auto, and, and, and? Doesn't make sense to me. Such smart alts are simply to give so called compliance with some regs dreamed up as good for us.

Thanks Graham g28 for that comprehensive explanation appreciate your help

Ok..basically a "smart" alternator is apart of an overall electronic management system of vehicles in the 2020's and has the capabilities of increasing or decreasing voltage output when required by the vehicle's ECU.
It means that the Engine ECU will dictate to the smart alternator what optimum voltage charge to put in the cranking battery based on feedback data to help run all the electronic components within the vehicle.
This means the smart alternator is not sending out a consistent voltage..it is always variable..where as with a convential alternator it just pumps out a predetermined voltage all day long.
So with a 2020's + model vehicles they have an overall electronic system that is designed as a "whole of vehicle" with the ECU being the brains of the whole outfit.
This means the 6, 8 or 10 speed auto has its own ECU unit and it communicated to the engine ECU..and voltage is critical for the electronic communication between these two components to function properly.
Basically you have two complex electronic computers communicating with each other within milli seconds, changing fuel / air mixture, fly by wire throttle response / stop -start/ wheel speed/gear ratios, steering inputs/ cabin environment..it is all highly orchestrated to function in sync..all this requires regulated prescribed voltage.
This is what vehicle manufactures have designed these days for the vehicles to meet various countries regulations and yes, customer demands, they want the bling.
If you try to put a regular alternator that pumps out a set voltage into that type of system and you are asking for trouble.. we are talking about of frying or damaging electronic components..which can be very very expensive.
Again this for vehicles post 2020..
I was speaking to a RACQ mechanic who's job it is too replace vehicle batteries..anyway..he received a job about a 2023 vehicle that was stalled near Coomera on the M1..he went out and found the driver.
The driver said the vehicle went from changing gears and driving well to getting stuck in first, the dash lit up like a xmas tree and would not upshift...and they also wanted to know why a battery mechanic was called out and not a flat bed truck, for the gearbox they believed had shite itself and it was nothing to do with the battery.
The mechanic hooked up his computer.. worked out what was the problem, then changed the battery and all was well with the vehicle.
He mentioned that he hooked up his computer for the hell of it..because the type of vehicle he was working on is known to have a CWM..(common with model) issue..
The limp mode, irregular gear changes is down to the electronics and inconsistent current..then change the battery.
This by the way was a service bulletin directive from the vehicle manufacturers' as a best short term fix for this type of situation..

What a load of crap Peter.
The ecu control of the alternator is purely for economy and emissions figures.
All of the "complex electronic computers" you mention have their own voltage regulation and filtering networks built in and operate on voltages well below charging voltages.

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There are a lot of beliefs and misconceptions expressed about "smart" or "variable-voltage" alternators.
Car manufactures are motivated to market their vehicles with the best fuel efficiency they can and compelled to conform to emission limitations. Accordingly they design in accordance with these factors and one area of attention is the alternator/battery charging.

To describe it concisely…………..
The alternator imposes a load on the engine which can be lessened by the vehicle ECU controlling the alternator output. At engine idle, typically at traffic control signals, engine emissions are very high and can be reduced by shutting down the alternator and hence reducing engine load. During acceleration, engine load is reduced by reducing alternator output thus less throttle is required which improves economy and lessens emissions. During deceleration, some energy can be recovered by increasing alternator output. These, and other alternator actions are determined by the algorithm in the ECU which takes into account the battery SoC and vehicle electrical needs. All these apparently minor actions add up to perceptible improvement in vehicle performance benefits but are unlikely to be noticed by a driver.

The negatives can be seen as difficulty when wishing to use the alternator for charging that is not part of the vehicle design (aux battery) and possible life reduction of the vehicle battery (arguable and unproven). These issues can be overcome by using an appropriate DC-DC charger for the auxiliary battery or by modification of the variable-voltage charging system. Such modification may have unnoticeable effect on vehicle handling but could cause the vehicle emissions behaviour to exceed legal requirements.

The above information has been gleaned from various respectable sources which did not include an RACQ mechanic.

Well, I will that one go through to the keeper.
To which one has to retort..

The point I was trying to make is that with modern vehicles from 2011 onwards vehicles have moved towards integration to where we are today in 2024 with highly integrated electronically controlled vehicles.
At the heart of all this is the battery and how it is charged and discharges current through the vehicle to these various electronic components..
Yes as one has mentioned..all these components have their own voltage regulation and filtering networks to operate and operate at voltages well below charging rates.
That is not in dispute..
In respect to using the wording "frying" that was a bit liberal...
I should have written "lessen their operational lifespan"..
What I will stand by though....
Is because of the complexity and component integration in modern vehicles.
The days of running a 6 B&S dual core wire from the start battery to an Anderson plug hanging off the tow bar on a 2023 model vehicle and wanting to charge a battery bank in a caravan..is now a thing of the past.
Then or thinking of putting on a "High output alternator" and doing the same thing..ie running the wire from the battery to an Anderson plug on a 2023 vehicle...more trouble than it is worth.
People I know in the vehicle repair business are pretty switched on, one being a auto elect who had worked for Australian state police force wiring up the police vehicles with all the stuff they have and I prettywell think..what he has been mentioning to me...I don't think he speaks crap.

Get a decent reputable DCDC charger..$350.00+ depending an output amp's..ie 20A, 30A etc and bling..ie built in MPPT, Bluetooth and that stuff..

Then there is the roadside battery mechanic and respectable resources.

My mum always said to me.."you never judge a book by it's cover.."
When you speak to people working on your vehicle you get to chatting as one does..
I found out a few things about this "road side battery mechanic"..
Interesting bloke he was...
He use to work between Broadmeadows and Geelong for about 15 years as a Automotive Electronics Engineer..he took a payout from his employer (whom he did not mention at all, by the way)..packed up the family and moved to the Gold Coast and does his job a couple a days a week..
He gave me a word about some of the modern vehicles these days..
Vehicle manufactures tender out manufacture of components they.. electronics components just being one.
What he was finding was that..
Vehicle wiring looms and connectors..have deteriorated in quality, also on how they are packaged by and arrive from 3rd party manufacturers, on how they are stored and then handled pre assembly and put into vehicles during assembly over the last 10 years.

@Peter g28

"The days of running a 6 B&S dual core wire from the start battery to an Anderson plug hanging off the tow bar on a 2023 model vehicle and wanting to charge a battery bank in a caravan..is now a thing of the past.
Then or thinking of putting on a "High output alternator" and doing the same thing..ie running the wire from the battery to an Anderson plug on a 2023 vehicle...more trouble than it is worth."

Absolute nonsense - my car is a 2007 - has a smart alternator, car is full of ECUs and runs a 200amp alternator - no issues in my vehicle.

I do concede that in some cases a Dc Dc charger is best but to simply charge normal lead acid/AGM or Deep Cycles - is not an issue.

Your vehicle is 2007...
I wrote about a plated 2023 vehicle..

Not relevant if the if the alternator and car systems are basically the same - what counts are the systems - not the build date of the vehicle.

Thanks RMD the batteries are under the kitchen table seat in the middle of the van they are SSB dry cell deep cycle
HVT -70 ZZD .
I am open for suggestions on where to mount a dcd charger either with the batteries and caravan control bits in the centre of the caravan or maybe in the front boot closer to the drawbar and what amperage charger and type

Nick.
As other have indicated, the charger is best close to the battery so the charger can have minimal resistance of cabling from/to the battery, so it knows battery charge voltage as accurately as possible and it's delivery isn't affected to any degree by resistance of cables.
Same as mentioned by others the cables from/to the van via Anderson have to be fairly good gauge size otherwise the cables to the Anderson become a significant resistance while under the current load drawn by the DC DC unit. The DCDC unit will be working hard to charge two 100ah if down a bit so will heat up as it operates. Sufficient cooling is essential so the DC DC doesn't go into self protection mode to save itself because of self generated heat as it does it's thing. You want it to be operating within it's normal ability.
I recently bought another small clamp meter to measure charge currents actually happening under certain conditions in a system of mine. Voltage readings is ok to know, but having ability to measure current flow amounts is really handy. With that info you can also test with, a multi meter and a bit of wire to extend the meter, to each cables end to end voltage, ie, the voltage difference between supply end and battery end of each conductor to find any sus cables or connections, while it is charging.
It is all a balance with supply cable sizes and lengths, DCDC charge current ability . Charging two half discharged 100 ah batteries will be similar to 1 fully discharged 100ah but they are usually 20amp charge input current rated. So you probably need near a 40 amp DCDC unit to fully charge the batteries in a relatively short time. Many are that size. Many don't consider the alternator cable from it's output terminal, (in most cases) is far smaller than the cables use to caravans Anderson plugs.
I had HJ61 with bigger than 100amp output. The alt cable to battery used to get HOT while under vehicle battery and aux battery charging loads. I replaced it with a larger cable.

One thing to consider is, maybe to limit cable sizes required for two batteries, only charge one at a time in the van via a heavy changeover switch like marine systems, one can be charged for a couple of hours and then the other, and there is then no huge load on anything at any one time. Each with a couple of hours charging will be much the same and then can be connected together again in parallel for the final stage. More fiddly to monitor, but can be a way to do it. Saves running a vehicle alternator at max for hours which it isn't designed to do if batteries were fairly discharged. No good having a fantastic system and a fried alternator. I carry a small Honda engine with small alt to at least charge something into the batteries if the alt failed. Can be used to run and maintain vehicle while driving if needed.

I found a BRAND NEW battery isolation switch I use has 2 Ohms resistance across it's 200AMP terminals. It caused heating inside the unit at around 50 to 80 amp discharge into an inverter. Current readings changed when contacts were cleaned. all good. Always test across all connections. saves heartache later.

RMD . Thank you ..
you have brought up a few good ideas for me to consider . What sort of switch would I use between the two batteries that would also allow me to draw on both battery as well

we were thinking of adding a Honda generator aswel for situations like we hadEaster monday w heavy rain and no sunshine ran down the batteries quickly to a point where the caravan management shut down from low voltage ..
which brings me to an another point why would the caravan's battery monitor show half an amp draw while on battery power when nothing is being used .

Nick
I have used a Marine switch. can't tell you the brand but are common. They allow charge to be directed into 1 battery, OR the other one, OR both at same time, ie, normal situation.
I blew up my 40 amp switchmode power supply for emergency charging so bought a 20 amp Switchmode supply off the net. Search LED DRIVER supply. They usually have an adjusting pot on them to crank above 12v maybe 13. 4v to 13.6 or so. Not the full amount for AGM batteries but will get them pumped up a bit. They come with a perforated mesh cover and you add your own 240 cable and 12v output leads. Some safety for use of those has to be observed , definitely not water proof, but it is only for emergency usage. Way better than a normal Eu1 or Eu2 Honda and it's piddly full throttle and noise 8 amp at slightly above 12v. You can buy bigger output devices than 20 amp though.

All solar regulators have a base standing/idle current use for their circuit to be "alive" ready. You might be seeing that base current use. If connected to batteries and NO SOLAR then the reg will flatten the batteries over time.

My emergency Honda is only a 25CC Whipper snipper motor with centrifugal clutch removed and small to bigger pulley drive. about 15 amps.

RMD the marine switch is that a manual operation if so thats what i have in my boat & very cheap to buy < $40

Interesting your emergency charger ..& why do you think/say better than a Honda ?
I thought those Honda's were pretty good , quiet & portable if camping alone .

Cheers nick

I run a 60 amp charger from my EU1 Honda gennie no problems. Super quick to charge up my lithium batteries.

G'Day Nick.
I wasn't downing the Eu1or Eu2 Hondas at all, I have an Eu2 but for space reasons the little unit can be good in emergencies. As BigFish said, My switchmode charger used to run from the Eu2 but it got moisture inside and fizzed, loud bang actually. For battery recharge the bigger charger and a Eu1 is great. not too big or heavy.

The marine switch is a about 80mm square and has a RED large dia knob. Probably the same as what you have, they are commonly used. Just check across the input terminal and the, to battery terminal/s, when carrying current, to detect any resistance heating voltage drop. Just to make sure so trouble isn't waiting to strike.

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Nice young fella Tony but I think he should reconsider his expression that it is a "mistake that EVERYONE makes".
Except him of course.

Oh, your link worked for me.

Haha Allan . I've seen this Youngster b4 and have decided not to follow or like
more about his subscribers then anything else IMO .
Thanks Tony for the link anyway worked for me as well

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Well Nick, he's giving it a go which is more than I can say for some. He will learn with time.
I really care about young people. They are the world's future but they are inheriting a pretty poor playing field.

Colin rivers (however it's spelled) started being an expert with little to no more experience than his own set up and no formal training at all.
He relied heavily on his so called friends to spoon feed him information for his early books.

Tonysmc
I know it is the way people say things and see things, but 32.5mm2 is ACTUALLY 1,056.25 SquareMM. Quite a large cable size! perhaps what is meant is 32.5 Sq mm, ie, 1 Sqmm area X 32.5.
There is always a big difference between the two because they mean entirely different concepts.
100mm X 10mm is 1000 sq mm a big slab of copper.

An 8mm x 8mm copper bar is 64Sqmm area/cross section and an 8mm dia copper bolt is just over 50 SQUARE Millimetres in area. An 8MM dia copper cable is fairly good size. Bigger than most. vehicle starter motor cables.

I commented on that YT blokes site. Now I avoid his presentations. I unsubscribed immediately after the first unwatched viewing.

So true RMD.
The most important dimention for selecting cable/terminal sizes is the diameter of the conductor but is never mentioned. EG,without being anal and looking up all the specifics, battery cable will need a greater diameter terminal than the same conductor surface area of weldflex because of the diameter of the individual strands.
Unfortunate thing is even if a 1056mm2 cable was used there would still be voltage drop.

Looking up cable charts, I see the producers of those charts, often cable suppliers, ALSO say mm2 instead of Sq mm. Not sure why they follow that path. Obviously not part of early childhood education re, AREA in a maths class.

Similar errors:
During Covid we were supposed to stand apart and the same problem. Do I stand in the size 2m2 which is 4 sq metres or in an area 1m x 2m which is 2 sq m total and far less distance away. = 1.4m away. Rules are Rules! Does the 600mm closer put you in danger? The virus size was /is 400 to 600 times smaller than EVERY breathing hole in a blue mask mesh. A bit like using concrete reo mesh to stop blowflies.

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Hi Qldcamper,

Collyn Rivers certainly does have some "formal training". Although leaving school early, he joined the RAF at age 17 and trained in ground radar. He also studied in mechanical engineering. Later employment in electronic research and manufacturing organisations added to his knowledge. He has published a number of electronic magazines and caravan/motorhome publications. He received much acclaim for his achievements. To say that he had "little to no more experience than his own set up" would be something of an inexactitude.

Collyn was a member and contributor here on ExplorOz for a time until he became so frustrated by people criticising him groundlessly and resigned his membership and contribution.
Although I did not always agree on some of Collyn's expressions I do respect his experience and knowledge and his uncomplicated articulation.

I would add that while I believe formal education to be valuable, I consider self-research and personal experience can provide a person with commensurate knowledge and understanding. I am less impressed by some others who gain a little knowledge then present themselves as unquestionable experts.

I think you are right you,you cannot buy experience.

qldcamper, What was the point of that disgusting, slanderous attack you made on Collyn Rivers? None of it is true.

He received formal training in electronics in the RAF whilst working on radar. Later he was an engineer who designed and constructed the instrumentation for testing the dynamics motor vehicles at GMH Vauxhall. You can read a fuller resume of his experience in A brief biography about Collyn Rivers. He may be largely self-taught but no one spoon-fed him. He did his own research by going to reliable publications, not by spoon-feeding. You could see that by the collection of books he had on his areas of interest. The engineering books he collected before and during the time he was publishing articles on caravan dynamics were quite heavy going. Nobody on these forums could have spoon-fed the depth of knowledge he gleaned from those books.

Your attacks on Collyn reveal more about your knowledge and ethics. I, for one, will not be taking much notice of your replies from now on.

RMD, your dissertations fall a little flat when you posted on Apr 05, 2024 at 20:02 The symbol mm2 is the symbol we commonly use for square millimetres.

I stand corrected.

Nomadic Navara
As I said. Most people "see it that way" and it is used that way, somehow. I hope you don't go and buy floor tiles using the same thinking because buying 6metres squared is 36 Square metres of area of tiles.. not 6 square metres.
Just because electrical norms may say it that way, and I know what they are meaning, doesn't make what we learned in school incorrect regarding area.

RMD, I don't know what YOU learnt in school regarding area, but mm2 and m2 are widely used terminology throughout industry, and not just electrical.

Tiles? We just finished a bathroom reno. All the paperwork from suppliers/contractor references m2 as the number of square meters.

VOTLAGE DROP =
[cable length (in metres) X current (in amps) X 0.0164] divided by cable cross-section in mm.sq.
Cable length must include both +ve and -ve cables.
(First supplied to me by Collyn Rivers in 2004)
Cheers,
Peter
OKA196 motorhome

Zippo
You are the second one to confirm what I said. The terms are used that way but ARE INCORRECT in their usage and application. No one seems to want to show 3.25 SQUARE MILLIMETRE AREA as the area of the end of a cable. ie, 1+1+1+.25 sq mm. They call it 3.25 mm 2 which is in REALITY 10.56 SQmm area. Crazy isn't it?

I give up ...

Zippo, just ignore him and he will go away.

Allan,
Self research is good but unfortunatly these days almost everyone uses forums or other websites to do their research where 70% of the information is based on hearsay and myths created by idiots and perpetuated by other idiots that believe it cause it was written.
I was trying to pick up some tips of 3 way fridge installation many years ago and ended up on someone's site(previously mentioned but I can't say it again because he seems to have a few sheep on here).
I was reading and learning a bit but then I clicked on the menu and saw a charging section.
It started of saying first you have to understand how an alternator works(reasonable statement but probably un necessary) and proceeded to give his understanding of how they worked.
Completely wrong, he obviously had no idea and misunderstood what his "friend" told him, or maybe his friend did it as a joke.
That made me doubt everything I had read on his sites and have never had any faith in anything he has ever written since.

Peter,
I'm not saying it's incorrect because I simply can't be bothered checking your VD formula against manufactures specs and using ohms law which is the advice I would give rather than work out a one formula suits all.
Have you? Or have you just assumed it's validity. Have you repeated it to others without actually varifying it?

Wow, my post seemed to spark a lot of responses! Yes, I’m not sure why they have gone that way, but I was just using what seems to be the standard that’s been adopted and seems to be the way it’s referred to in charts. (A bit like trailer plugs). The only reason I mentioned this video in particular, is it seemed similar to the set up the OP was asking about and showed a practical/visual demonstration of voltage drop due to length and wire size which I thought was good example for spending a little extra in the first place rather than have to upgrade later.

Tony

Hmmm, after all the above I'm not wondering why Collyn Rivers buggared off.

.
Exactly.

Collyn Rivers who I have no idea is..
is OFF TOPIC !! conversation in this post please keep it on topic and relevant to the subject before the mods don't lock or delete this post please
Regards nickb .

Sorry Nick but that will never happen on this forum. Every thing turns into a pissing contest.